A solid-state battery is a
battery
Battery most often refers to:
* Electric battery, a device that provides electrical power
* Battery (crime), a crime involving unlawful physical contact
Battery may also refer to:
Energy source
*Automotive battery, a device to provide power t ...
technology that uses solid
electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...
s and a
solid electrolyte, instead of the liquid or
polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
gel electrolytes found in
lithium-ion
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also sees ...
or
lithium polymer
A lithium polymer battery, or more correctly lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly, lithium-poly and others), is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyt ...
batteries.
While solid electrolytes were first discovered in the 19th century, several drawbacks have prevented widespread application. Developments in the late 20th and early 21st century have caused renewed interest in solid-state battery technologies, especially in the context of
electric vehicle
An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery (sometimes cha ...
s, starting in the 2010s.
Solid-state batteries can provide potential solutions for many problems of liquid Li-ion batteries, such as flammability, limited voltage, unstable solid-electrolyte interphase formation, poor cycling performance and strength.
Materials proposed for use as solid electrolytes in solid-state batteries include ceramics (e.g., oxides, sulfides, phosphates), and solid polymers. Solid-state batteries have found use in
pacemakers
An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a Implant (medicine), medical device that generates electrical impulses delivered by electrodes to the Heart ...
,
RFID
Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromag ...
and
wearable devices. They are potentially safer, with higher energy densities, but at a much higher cost. Challenges to widespread adoption include energy and
power density
Power density is the amount of power (time rate of energy transfer) per unit volume.
In energy transformers including batteries, fuel cells, motors, power supply units etc., power density refers to a volume, where it is often called volume p ...
,
durability
Durability is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its design lifetime. There are several measures of durability in use, ...
,
material costs
Direct materials cost the cost of direct materials which can be easily identified with the unit of production. For example, the cost of glass is a direct materials cost in light bulb manufacturing.
The manufacture of products or goods required ma ...
, sensitivity and stability.
History
Between 1831 and 1834,
Michael Faraday
Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic inducti ...
discovered the solid electrolytes
silver sulfide
Silver sulfide is an inorganic compound with the formula . A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver obje ...
and
lead(II) fluoride
Lead(II) fluoride is the inorganic compound with the formula Pb F2. It is a white solid. It exists as both an orthorhombic and cubic forms.
Uses
Lead(II) fluoride is used in low melting glasses, in glass coatings to reflect infrared rays, ...
, which laid the foundation for
solid-state ionics
Solid-state ionics is the study of ionic-electronic mixed conductor and fully ionic conductors ( solid electrolytes) and their uses. Some materials that fall into this category include inorganic crystalline and polycrystalline solids, ceramics, g ...
.
By the late 1950s, several silver-conducting electrochemical systems employed solid electrolytes, but such systems possessed undesirable qualities, including low energy density and cell voltages, and high internal resistance.
In 1967, the discovery of fast ionic conduction β - alumina for a broad class of ions (Li+, Na+, K+, Ag+, and Rb+) kick-started excitement for and the development of new solid-state electrochemical devices with increased energy density.
Most immediately, molten sodium / β - alumina / sulfur cells were developed at Ford Motor Company in the US, and NGK in Japan.
This excitement for solid-state electrolytes manifested in the discovery of new systems in both organics, i.e. poly(ethylene) oxide (PEO), and inorganics such as NASICON.
However, many of these systems commonly required operation at elevated temperatures, and / or were expensive to produce, enabling only limited commercial deployment.
A new class of solid-state electrolyte developed by the
Oak Ridge National Laboratory
Oak Ridge National Laboratory (ORNL) is a U.S. multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research and ...
, Lithium phosphorus oxynitride (LiPON), emerged in the 1990s. While LiPON was successfully used to make
thin film lithium-ion batteries,
such applications were limited due to the cost associated with deposition of the thin-film electrolyte, along with the small capacities that could be accessed using the thin film format.
In 2011, the landmark work of Kamaya et al. demonstrated the first solid-electrolyte, Li
1.5Al
0.5Ge
1.5(PO
4)
3 (LAGP), capable of achieving a bulk ionic conductivity in excess of liquid electrolyte counterparts at room temperature. With this, bulk solid-ion conductors could finally compete technologically with Li-ion counterparts, leading to the modern era of solid-state research.
2000's commercial research & development
As technology advanced into the new millennium, researchers and companies in the automotive and transportation industries experienced revitalized interest in solid-state battery technologies. In 2011,
Bolloré
Bolloré SE () is a French conglomerate headquartered in Puteaux, on the western outskirts of Paris, France. Founded in 1822, the company has interests in Vivendi, international freight forwarding, oil storage and pipelines in France, solid state ...
launched a fleet of their BlueCar model cars, first in cooperation with carsharing service
Autolib
Autolib' was an electric car sharing service which was inaugurated in Paris, France, in December 2011. It closed on 31 July 2018. It was operated by the Bolloré industry and complemented the city's bike sharing system, Velib', which was set u ...
, and later released to retail customers. The car was meant to showcase the company's diversity of electric-powered cells in the application, and featured a 30 kWh lithium metal polymer (LMP) battery with a polymeric electrolyte, created by dissolving lithium salt in a co-polymer (
polyoxyethylene
Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular we ...
).
In 2012,
Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
soon followed suit and began conducting experimental research into solid-state batteries for applications in the automotive industry in order to remain competitive in the
EV market. At the same time,
Volkswagen
Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...
began partnering with small technology companies specializing in the technology.
A series of technological breakthroughs ensued. In 2013, researchers at the
University of Colorado Boulder
The University of Colorado Boulder (CU Boulder, CU, or Colorado) is a public research university in Boulder, Colorado. Founded in 1876, five months before Colorado became a state, it is the flagship university of the University of Colorado syst ...
announced the development of a solid-state lithium battery, with a solid composite
cathode
A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
based on an
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
-
sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...
chemistry, that promised higher energy capacity compared to already-existing SSBs.
In 2017,
John Goodenough
John Bannister Goodenough ( ; born July 25, 1922) is an American materials scientist, a solid-state physicist, and a Nobel laureate in chemistry. He is a professor of Mechanical, Materials Science, and Electrical Engineering at the University ...
, the co-inventor of Li-ion batteries, unveiled a solid-state battery, using a
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
electrolyte and an
alkali
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...
-metal
anode
An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
consisting of
lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
,
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
or
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
.
Later that year,
Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
announced the deepening of its decades-long partnership with
Panasonic
formerly between 1935 and 2008 and the first incarnation of between 2008 and 2022, is a major Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation, headquartered in Kadoma, Osaka, Kadoma, Osaka P ...
, including a collaboration on solid-state batteries.
Due to its early intensive research and coordinated collaborations with other industry leaders,
Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
holds the most SSB-related patents. However, other car makers independently developing solid-state battery technologies quickly joined a growing list that includes
BMW,
Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
,
Hyundai Motor Company
Hyundai Motor Company, often abbreviated to Hyundai Motors ( )
and commonly known as Hyundai (, ; ), is a South Korean multinational automotive manufacturer headquartered in Seoul, South Korea, and founded in 1967. Currently, the company o ...
and
Nissan
, trade name, trading as Nissan Motor Corporation and often shortened to Nissan, is a Japanese multinational corporation, multinational Automotive industry, automobile manufacturer headquartered in Nishi-ku, Yokohama, Japan. The company sells ...
. Other automotive-related companies, such as
Spark plug
A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air ...
maker
NGK, have retrofitted their business expertise and models to cater to evolving demand for ceramic-based solid state batteries, in the face of perceived obsolescence of the conventional fossil-fuel paradigm.
Major developments continued to unfold into 2018, when Solid Power, spun off from the University of Colorado Boulder research team, received $20 million in funding from
Samsung
The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
and
Hyundai Hyundai is a South Korean industrial conglomerate ("chaebol"), which was restructured into the following groups:
* Hyundai Group, parts of the former conglomerate which have not been divested
** Hyundai Mobis, Korean car parts company
** Hyundai ...
to establish a small manufacturing line that could produce copies of its all-solid-state, rechargeable lithium-metal battery prototype, with a predicted 10
megawatt hours of capacity per year.
QuantumScape
QuantumScape is an American company that develops solid state lithium metal batteries for electric cars. The company is headquartered in San Jose, California and employs around 400 people. Investors include Bill Gates and Volkswagen.
History ...
, another solid-state battery startup that spun out of a collegiate research group (in this case,
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...
) drew attention that same year, when
Volkswagen
Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...
announced a $100 million investment into the team's research, becoming the largest stakeholder, joined by investor
Bill Gates
William Henry Gates III (born October 28, 1955) is an American business magnate and philanthropist. He is a co-founder of Microsoft, along with his late childhood friend Paul Allen. During his career at Microsoft, Gates held the positions ...
. With the goal to establish a joint production project for mass production of solid-state batteries, Volkswagen endowed QuantumScape with an additional $200 million in June 2020, and QuantumScape
IPO
An initial public offering (IPO) or stock launch is a public offering in which shares of a company are sold to institutional investors and usually also to retail (individual) investors. An IPO is typically underwritten by one or more investment ...
'd on the
NYSE
The New York Stock Exchange (NYSE, nicknamed "The Big Board") is an American stock exchange in the Financial District, Manhattan, Financial District of Lower Manhattan in New York City. It is by far the List of stock exchanges, world's largest s ...
on November 29, 2020, as part of a merger with Kensington Capital Acquisition, to raise additional equity capital for the project.
QuantumScape has "scheduled mass production to begin in the second half of 2024".
[
Qing Tao started the first Chinese production line of solid-state batteries in 2018 as well, with the initial intention of supplying SSBs for “special equipment and high-end digital products”; however, the company has spoken with several car manufacturers with the intent to potentially expand into the automotive space.
In July 2021, ]Murata Manufacturing
is a Japanese manufacturer of electronic components, based in Nagaokakyo, Kyoto.
Honorary Chairman Akira Murata started Murata Manufacturing as a personal venture in October, 1944. In December 1950 reorganized the company into Murata Manufac ...
announced that it will begin mass production of all-solid-state batteries in the coming months, aiming to supply them to manufacturers of earphones and other wearables.
The battery capacity is up to 25mAh at 3.8V, making it suitable for small mobile devices such as earbuds, but not for electric vehicles. Lithium-Ion cells used in electric vehicles typically offer 2,000 to 5,000 mAh at similar voltage: an EV would need at least 100 times as many of the Murata cells to provide equivalent power.
Ford Motor Company
Ford Motor Company (commonly known as Ford) is an American multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. The company sells automobi ...
and BMW funded the startup Solid Power with $130 million, and as of 2022 the company has raised a total of $540 million.
In September 2021, Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
announced their plan to use a solid-state battery in some future car models, starting with hybrid models in 2025, due to the cost and lower power requirements.
In January 2022, ProLogium Technology signed a technical cooperation agreement with Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...
, a subsidiary of the Daimler Group. The money invested by Mercedes-Benz will be used for solid-state battery development and production preparations.
In February 2022, Alpine 4 Holdings subsidiaries Elecjet and Vayu Aerospace successfully installed Solid State Batteries in their Drones leading up to a sale to a Government Contractor later in the year.
In July 2022, Svolt announced the production of a 20 Ah electric battery with an energy density
In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or .
Often only the ''useful'' or extract ...
of 350-400 Wh/kg.
Materials
Solid-state electrolyte
A solid-state electrolyte (SSE) is a solid Ionic conductivity (solid state), ionic conductor and electron-insulating electrolyte, material and it is the characteristic component of the solid-state battery. It is useful for applications in electrica ...
s (SSEs) candidate materials include ceramics such as lithium orthosilicate
Lithium orthosilicate is a compound with the chemical formula Li4SiO4. It is a white ceramic compound, which melts congruently at a temperature of .
Lithium orthosilicate is of primary interest towards carbon dioxide capture, as this compound r ...
, glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
, sulfides and RbAg4I5. Mainstream oxide solid electrolytes include Li1.5Al0.5Ge1.5(PO4)3 (LAGP), Li1.4Al0.4Ti1.6(PO4)3 (LATP), perovskite-type Li3xLa2/3-xTiO3 (LLTO), and garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZO) with metallic Li. The thermal stability versus Li of the four SSEs was in order of LAGP < LATP < LLTO < LLZO. Chloride superionic conductors have been proposed as another promising solid electrolyte. They are ionic conductive as well as deformable sulfides, but at the same time not troubled by the poor oxidation stability of sulfides. Other than that, their cost is considered lower than oxide and sulfide SSEs. The present chloride solid electrolyte systems can be divided into two types: Li3MCl6 and Li2M2/3Cl4. M Elements include Y, Tb-Lu, Sc, and In. The cathodes are lithium based. Variants include LiCoO2, LiNi1/3Co1/3Mn1/3O2, LiMn2O4, and LiNi0.8Co0.15Al0.05O2. The anodes vary more and are affected by the type of electrolyte. Examples include In, Si, Ge''x''Si1−''x'', SnO–B2O3, SnS –P2S5, Li2FeS2, FeS, NiP2, and Li2SiS3.
One promising cathode material is Li-S, which (as part of a solid lithium anode/Li2S cell) has a theoretical specific capacity of 1670 mAh g−1, "ten times larger than the effective value of LiCoO2". Sulfur makes an unsuitable cathode in liquid electrolyte applications because it is soluble in most liquid electrolytes, dramatically decreasing the battery's lifetime. Sulfur is studied in solid state applications. Recently, a ceramic textile was developed that showed promise in a Li-S solid state battery. This textile facilitated ion transmission while also handling sulfur loading, although it did not reach the projected energy density. The result "with a 500-μm-thick electrolyte support and 63% utilization of electrolyte area" was "71 Wh/kg." while the projected energy density was 500 Wh/kg.
Li-O2 also have high theoretical capacity. The main issue with these devices is that the anode must be sealed from ambient atmosphere, while the cathode must be in contact with it.
A Li/ LiFePO4 battery shows promise as a solid state application for electric vehicles. A 2010 study presented this material as a safe alternative to rechargeable batteries for EV's that "surpass the USABC-DOE targets".
A cell with a pure silicon μSi, , SSE, , NCM811 anode was assembled by Darren H.S Tan et al. using μSi anode(purity of 99.9 wt %), solid state electrolyte (SSE) and lithium nickel cobalt manganese oxide (NCM811) cathode. This kind of solid state battery demonstrated a high current density up to 5 mA cm−2, a wide range of working temperature (-20 °C and 80 °C), and areal capacity (for the anode) of up to 11 mAh cm−2 (2890 mAh/g). At the same time, after 500 cycles under 5 mA cm−2, the batteries still provide 80% of capacity retention, which is the best performance of μSi all solid-state battery reported so far.
Chloride solid electrolytes also show promise over conventional oxide solid electrolytes owing to chloride solid electrolytes having theoretically higher ionic conductivity and better formability. In addition chloride solid electrolyte’s exceptionally high oxidation stability and high ductility add to its performance. In particular a lithium mixed-metal chloride family of solid electrolytes, Li2InxSc0.666-xCl4 developed by Zhou et tal., show high ionic conductivity (2.0 mS cm−1) over a wide range of composition. This is owing to the chloride solid electrolyte being able to be used in conjunction with bare cathode active materials as opposed to coated cathode active materials and its low electronic conductivity. Alternative cheaper chloride solid electrolyte compositions with lower, but still impressive, ionic conductivity can be found with an Li2ZrCl6 solid electrolyte. This particular chloride solid electrolyte maintains a high room temperature ionic conductivity (0.81 mS cm−1), deformability, and has a high humidity tolerance.
Uses
Solid-state batteries are potentially useful in pacemakers
An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a Implant (medicine), medical device that generates electrical impulses delivered by electrodes to the Heart ...
, RFIDs, wearable devices
Wearable technology is any technology that is designed to be used while worn. Common types of wearable technology include smartwatches and smartglasses. Wearable electronic devices are often close to or on the surface of the skin, where they detec ...
, and electric vehicle
An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery (sometimes cha ...
s.
Electric vehicles
Hybrid and plug-in electric cars use a variety of battery technologies, including Li-ion, nickel–metal hydride (NiMH), lead–acid, and electric double-layer capacitor
A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable b ...
(or ultracapacitor), with Li-ion dominating the market.
In August 2020, Toyota
is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. It was founded by Kiichiro Toyoda and incorporated on . Toyota is one of the largest automobile manufacturers in the world, producing about 10 ...
started road testing of their prototype vehicle, LQ Concept, equipped with a solid-state battery.
In September 2021, Toyota unveiled its strategy on battery development and supply, in which solid-state battery is to be adopted first in their hybrid electric vehicle
A hybrid electric vehicle (HEV) is a type of hybrid vehicle that combines a conventional internal combustion engine (ICE) system with an electric propulsion system ( hybrid vehicle drivetrain). The presence of the electric powertrain is intende ...
s to utilize its characteristics.
And, Honda
is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan.
Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...
has set their plan schedule to start operation of demonstration line for the production of all-solid-state batteries in Spring 2024.
Wearables
The characteristics of high energy density and keeping high performance even in harsh environments are expected in realization of new wearable devices that are smaller and more reliable than ever.
Equipment in space station
In March 2021, an industrial manufacturer Hitachi Zosen Corporation
is a major Japanese industrial and engineering corporation. It produces waste treatment plants, industrial plants, precision machinery, industrial machinery, steel mill process equipment, steel structures, construction machinery, tunnel boring ma ...
has developed a solid-state battery, claiming to have one of the highest capacities in the industry, and explained about its usage in harsh conditions in space environment. They have already made agreement with the Japan Aerospace Exploration Agency (JAXA) to test their solid-state batteries in space, and the battery will power camera equipment in Japan's Experiment Module ''Kibō'' on the International Space Station
The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...
(ISS).
Drones
Being lighter weight and more powerful than traditional lithium ion batteries it is resonable that Drones would benefit from Solid State batteries. Vayu Aerospace a drone manufacturer and designer noted an increased flight time after they incorporated them into their G1 long flight drone.
Challenges
Cost
Thin-film solid-state batteries are expensive to make and employ manufacturing processes thought to be difficult to scale, requiring expensive vacuum deposition
Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure (i.e., vacuum). The deposited layers can r ...
equipment. As a result, costs for thin-film solid-state batteries become prohibitive in consumer-based applications. It was estimated in 2012 that, based on then-current technology, a 20 Ah solid-state battery cell would cost US$
The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...
100,000, and a high-range electric car would require between 800 and 1,000 of such cells. Likewise, cost has impeded the adoption of thin film solid-state batteries in other areas, such as smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
s.
Temperature and pressure sensitivity
Low temperature operations may be challenging. Solid-state batteries historically have had poor performance.
Solid-state batteries with ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
electrolytes require high pressure to maintain contact with the electrodes. Solid-state batteries with ceramic separators may break from mechanical stress.
In November 2022, Japanese research group, consisting of Kyoto University
, mottoeng = Freedom of academic culture
, established =
, type = National university, Public (National)
, endowment = ¥ 316 billion (2.4 1000000000 (number), billion USD)
, faculty = 3,480 (Teaching Staff)
, administrative_staff ...
, Tottori University
, abbreviated to , is a national university in Japan. The main campus is located in Koyamachō-Minami, Tottori City, Tottori Prefecture. Another campus, the Faculty of Medicine, is located on the Yonago Campus in Yonago, Tottori.
History
Tottor ...
and Sumitomo Chemical
is a major Japanese chemical company. The company is listed on the first section of the Tokyo Stock Exchange and is a constituent of the on the Nikkei 225 stock index. It's a member of the Sumitomo group and was founded in 1913 as a fertilize ...
, announced that they have managed to operate solid-state batteries stably without applying pressure with 230Wh/kg capacity by using copolymerized new materials for electrolyte.
Interfacial resistance
High interfacial resistance between a cathode and solid electrolyte has been a long-standing problem for all-solid-state batteries.
Interfacial instability
The interfacial instability of the electrode-electrolyte has always been a serious problem in solid state batteries. After solid state electrolyte contacts with electrode, the chemical and/or electrochemical side reactions at the interface usually produce a passivated interface, which impedes the diffusion of Li+ across the electrode-SSE interface. Upon high-voltage cycling, some SSEs may undergo oxidative degradation.
Dendrites
Solid lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
(Li) metal anodes in solid-state batteries are replacement candidates in lithium-ion batteries
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...
for higher energy densities
In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or .
Often only the ''useful'' or extract ...
, safety, and faster recharging times. Such anodes tend to suffer from the formation and the growth of Li dendrites
Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the n ...
, non-uniform metal growths which penetrate the electrolyte lead to electrical short circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit ...
s. This shorting leads to energy discharge, overheating, and sometimes fires or explosion
An explosion is a rapid expansion in volume associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Supersonic explosions created by high explosives are known ...
s due to thermal runaway
Thermal runaway describes a process that is accelerated by increased temperature, in turn releasing energy that further increases temperature. Thermal runaway occurs in situations where an increase in temperature changes the conditions in a way t ...
. Li dendrites reduce coulombic efficiency Faraday efficiency (also called ''faradaic efficiency'', ''faradaic yield'', ''coulombic efficiency'' or ''current efficiency'') describes the efficiency with which charge (electrons) is transferred in a system facilitating an electrochemical reacti ...
.
The exact mechanisms of dendrite growth remain a subject of research. Studies of metal dendrite growth in solid electrolytes began with research of molten sodium / sodium - β - alumina / sulfur cells at elevated temperature. In these systems, dendrites sometimes grow as a result of micro-crack extension due to the presence of plating-induced pressure at the sodium / solid electrolyte interface. However, dendrite growth may also occur due to chemical degradation of the solid electrolyte.
In Li-ion solid electrolytes, dendrites propagate primarily due to pressure build up at the electrode / solid electrolyte interface, leading to crack extension.
Dendrite growth in solid-state Li-ion cells can be mitigated by operating the cells at elevated temperature, or by using residual stresses to fracture toughen electrolytes, thereby deflecting dendrites and delaying dendrite induced short-circuiting.
Mechanical failure
A common failure mechanism in solid-state batteries is mechanical failure
Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking and includes the study of past structural failures in order to ...
through volume changes in the anode and cathode during charge and discharge due to the addition and removal of Li-ions from the host structures.
Cathode
Cathodes will typically consist of active cathode particles mixed with SSE particles to assist with ion conduction. As the battery charges/discharges, the cathode particles change in volume typically on the order of a few percent. This volume change leads to the formation of interparticle voids
Void may refer to:
Science, engineering, and technology
* Void (astronomy), the spaces between galaxy filaments that contain no galaxies
* Void (composites), a pore that remains unoccupied in a composite material
* Void, synonym for vacuum, a s ...
which worsens contact
Contact may refer to:
Interaction Physical interaction
* Contact (geology), a common geological feature
* Contact lens or contact, a lens placed on the eye
* Contact sport, a sport in which players make contact with other players or objects
* ...
between the cathode and SSE particles, resulting in a significant loss of capacity due to the restriction in ion transport.
One proposed solution to this issue is to take advantage of the anisotropy
Anisotropy () is the property of a material which allows it to change or assume different properties in different directions, as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's physic ...
of volume change in the cathode particles. As many cathode materials experience volume changes only along certain crystallographic directions, if the secondary cathode particles are grown along a crystallographic direction which does not expand greatly with charge/discharge, then the change in volume of the particles can be minimized. Another proposed solution is to mix different cathode materials which have opposite expansion trends in the proper ratio such that the net volume change of the cathode is zero. For instance, LiCoO2 (LCO) and LiNi0.9Mn0.05Co0.05O2 (NMC) are two well-known cathode materials for Li-ion batteries. LCO has been shown to undergo volume expansion when discharged while NMC has been shown to undergo volume contraction when discharged. Thus, a composite cathode of LCO and NMC at the correct ratio could undergo minimal volume change under discharge as the contraction of NMC is compensated by the expansion of LCO.
Anode
Ideally a solid-state battery would use a pure lithium metal
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ele ...
anode due to its high energy capacity. However, lithium undergoes a large increase of volume during charge at around 5 µm per 1 mAh/cm2 of plated Li. For electrolytes with a porous microstructure, this expansion leads to an increase in pressure which can lead to creep of Li metal through the electrolyte pores and short
Short may refer to:
Places
* Short (crater), a lunar impact crater on the near side of the Moon
* Short, Mississippi, an unincorporated community
* Short, Oklahoma, a census-designated place
People
* Short (surname)
* List of people known as ...
of the cell. Lithium metal has a relatively low melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...
of 453K and a low activation energy
In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy (''E''a) of a reaction is measured in joules per mole (J/mol), kilojoules pe ...
for self-diffusion According to IUPAC definition, self-diffusion coefficient is the diffusion coefficient D_i^* of species i when the chemical potential gradient equals zero. It is linked to the diffusion coefficient D_i by the equation:
D_i^*=D_i\frac.
Here, a_i is ...
of 50 kJ/mol, indicating its high propensity to significantly creep at room temperature. It has been shown that at room temperature lithium undergoes power-law creep where the temperature is high enough relative to the melting point that dislocation
In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to sl ...
s in the metal can climb out of their glide plane In geometry and crystallography, a glide plane (or transflection) is a symmetry operation describing how a reflection in a plane, followed by a translation parallel with that plane, may leave the crystal unchanged.
Glide planes are noted by ''a'', ...
to avoid obstacles. The creep stress under power-law creep is given by:
Where is the gas constant
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per ...
, is temperature, is the uniaxial strain rate
In materials science, strain rate is the change in strain (deformation) of a material with respect to time.
The strain rate at some point within the material measures the rate at which the distances of adjacent parcels of the material change wi ...
, is the creep stress
Stress may refer to:
Science and medicine
* Stress (biology), an organism's response to a stressor such as an environmental condition
* Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
, and for lithium metal , , .
For lithium metal to be used as an anode, great care must be taken to minimize the cell pressure to relatively low values on the order of its yield stress
In materials science and engineering, the yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and wi ...
of 0.8 MPa. The normal operating cell pressure for lithium metal anode is anywhere from 1-7 MPa. Some possible strategies to minimize stress on the lithium metal are to use cells with springs of a chosen spring constant
In physics, Hooke's law is an empirical law which states that the force () needed to extend or compress a spring (device), spring by some distance () Proportionality (mathematics)#Direct_proportionality, scales linearly with respect to that ...
or controlled pressurization of the entire cell. Another strategy may be to sacrifice some energy capacity and use a lithium metal alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
anode which typically has a higher melting temperature than pure lithium metal, resulting in a lower propensity to creep. While these alloys do expand quite a bit when lithiated, often to a greater degree than lithium metal, they also possess improved mechanical properties allowing them to operate at pressures around 50 MPa. This higher cell pressure also has the added benefit of possibly mitigating void formation in the cathode.
Advantages
Solid-state battery technology is believed to deliver higher energy densities
In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or .
Often only the ''useful'' or extract ...
(2.5x).
They may avoid the use of dangerous or toxic materials found in commercial batteries, such as organic electrolytes.
Because most liquid electrolytes are flammable and solid electrolytes are nonflammable, solid-state batteries are believed to have lower risk of catching fire. Fewer safety systems are needed, further increasing energy density at the module or cell pack level. Recent studies show that heat generation inside is only ~20-30% of conventional batteries with liquid electrolyte under thermal runaway.
Solid-state battery technology is believed to allow for faster charging. Higher voltage and longer cycle life are also possible.
Thin film solid state batteries
Background
The earliest thin film solid state batteries is found by Keiichi Kanehori in 1986, which is based on the Li electrolyte. However, at that time, the technology was insufficient to power larger electronic devices so it was not fully developed. During recent years, there has been much research in the field. Garbayo demonstrated that “polyamorphism” exists besides crystalline states for thin film Li-garnet solid state batteries in 2018, Moran demonstrated that ample can manufacture ceramic films with the desired size range of 1–20 μm in 2021.
Structure
Anode materials: Li is favored because of its storage properties, alloys of Al, Si and Sn are also suitable as anodes.
Cathode materials: require having light weight, good cyclical capacity and high energy density. Usually include LiCoO2, LiFePO4, TiS2, V2O5and LiMnO2.
Preparation techniques
Some methods are listed below.
* Physical methods:
*# Magnetron sputtering (MS) is one of the most widely used processes for thin film manufacturing, which is based on physical vapor deposition.
*# Ion-beam deposition (IBD) is similar to the first method, however, bias is not applied and plasma doesn't occur between the target and the substrate in this process.
*# Pulsed laser deposition (PLD), laser used in this method has a high power pulses up to about 108 W cm−2.
*# Vacuum evaporation (VE) is a method to prepare alpha-Si thin films. During this process, Si evaporates and deposits on a metallic substrate.
* Chemical methods:
*# Electrodeposition (ED) is for manufacturing Si films, which is convenient and economically viable technique.
*# Chemical vapor deposition (CVD) is a deposition technique allowing to make thin films with a high quality and purity.
*# Glow discharge plasma deposition (GDPD) is a mixed physicochemical process. In this process, synthesis temperature has been increased to decrease the extra hydrogen content in the films.
Development of thin film system
* Lithium-Oxygen and Nitrogen based polymer thin film electrolytes has got fully used in solid state batteries.
* Non-Li based thin film solid state batteries have been studied, such as Ag-doped germanium chalcogenide thin film solid state electrolyte system. Barium-doped thin film system has also been studied, which thickness can be 2μm at least. In addition, Ni can also be a component in thin film.
* There are also other methods to fabricate the electrolytes for thin film solid state batteries, which are 1.electrostatic-spray deposition technique, 2. DSM-Soulfill process and 3. Using MoO3 nanobelts to improve the performance of lithium based thin film solid state batteries.
Advantages
* Compared with other batteries, the thin film batteries have both high gravimetric energy density and volumetric energy density. These are important indicators to measure battery performance of energy stored.
* In addition to high energy density, thin-film solid-state batteries have long lifetime, outstanding flexibility and low weight. These properties make thin film solid state batteries suitable for use in various fields such as electric vehicles, military facilities and medical devices.
Challenges
* Its performance and efficiency are constrained by the nature of its geometry. The current drawn from a thin film battery largely depends on the geometry and interface contacts of the electrolyte/cathode and the electrolyte/anode interfaces
* Low thickness of the electrolyte and the interfacial resistance at the electrode and electrolyte interface affect the output and integration of thin film systems.
* During the charging-discharging process, considerable change of volumetric makes the loss of material.
See also
* Solid-state electrolyte
A solid-state electrolyte (SSE) is a solid Ionic conductivity (solid state), ionic conductor and electron-insulating electrolyte, material and it is the characteristic component of the solid-state battery. It is useful for applications in electrica ...
* Divalent
In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules.
Description
The combining capacity, or affinity of an ...
* Fast ion conductor
In materials science, fast ion conductors are solid conductors with highly mobile ions. These materials are important in the area of solid state ionics, and are also known as solid electrolytes and superionic conductors. These materials are usefu ...
* Ionic conductivity
* Ionic crystal
In chemistry, an ionic crystal is a crystalline form of an ionic compound. They are solids consisting of ions bound together by their electrostatic attraction into a regular Crystal structure, lattice. Examples of such crystals are the alkali hal ...
* John B. Goodenough
* List of battery types
This list is a summary of notable electric battery types composed of one or more electrochemical cells. Three lists are provided in the table. The primary (non-rechargeable) and secondary (rechargeable) cell lists are lists of battery chemistry ...
* Lithium–air battery
The lithium–air battery (Li–air) is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.
Pairing lithium and ambient oxygen can ...
* Lithium iron phosphate battery
The lithium iron phosphate battery (LFP (lithium ferro-phosphate), or Li-IP) is a type of lithium-ion battery using lithium iron phosphate () as the cathode material, and a graphitic carbon electrode with a metallic backing as the anode.
Becaus ...
* Separator (electricity)
A separator is a permeable membrane placed between a battery's anode and cathode. The main function of a separator is to keep the two electrodes apart to prevent electrical short circuits while also allowing the transport of ionic charge carriers ...
* Supercapacitor
A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable ba ...
* Thin film lithium-ion battery
The thin film lithium-ion battery is a form of solid-state battery. Its development is motivated by the prospect of combining the advantages of solid-state batteries with the advantages of thin-film manufacturing processes.
Thin-film construction ...
References
Further reading
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External links
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