The lithium iron phosphate battery (LFP (lithium ferro-phosphate), or Li-IP) is a type of
lithium-ion battery
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 s ...
using
lithium iron phosphate
Lithium iron phosphate or lithium ferro-phosphate (LFP) is an inorganic compound with the formula . It is a gray, red-grey, brown or black solid that is insoluble in water. The material has attracted attention as a component of lithium iron phosp ...
() as the
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 wh ...
material, and a
graphitic carbon electrode
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on larg ...
with a metallic backing as the
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 ...
.
Because of their lower cost, high safety, low toxicity, long cycle life and other factors, LFP batteries are finding a number of roles in
vehicle use, utility-scale stationary applications, and
backup power
An emergency power system is an independent source of electrical power that supports important electrical systems on loss of normal power supply. A standby power system may include a standby generator, batteries and other apparatus. Emergency p ...
. LFP batteries are cobalt-free. As of Q1 2021, LFP type battery market share reached 24.1%, with
Chinese manufacturers holding a near monopoly, and is expected to rise further to surpass
NMC type batteries in 2028.
The
energy density of an LFP battery is lower than that of other common lithium ion battery types such as
nickel manganese cobalt (NMC) and
nickel cobalt aluminum (NCA), and also has a lower operating
voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...
;
CATL
Contemporary Amperex Technology Co. Limited (), abbreviated as CATL, is a Chinese battery manufacturer and technology company founded in 2011 that specializes in the manufacturing of lithium-ion batteries for electric vehicles and energy storage ...
's LFP batteries are currently at 125
watt hour
A kilowatt-hour ( unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bi ...
s (Wh) per kg, up to possibly 160 Wh/kg with improved packing technology, while
BYD's LFP batteries are at 150 Wh/kg, compared to over 300 Wh/kg for the highest
NMC batteries. Notably, the energy density of Panasonic’s “2170” NCA batteries used in 2020 in Tesla’s Model 3 is around 260 Wh/kg, which is 70% of its "pure chemicals" value.
History
is a natural mineral of the
olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
family (
).
Arumugam Manthiram
Arumugam Manthiram (; born March 15, 1951) is an American materials scientist and engineer, best known for his identification of the polyanion class of lithium ion battery cathodes, understanding of how chemical instability limits the capacity of ...
and
John B. Goodenough first identified the polyanion class of cathode materials for
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 see ...
. was then identified as a cathode material belonging to the polyanion class for use in batteries in 1996 by Padhi et al. Reversible extraction of lithium from and insertion of lithium into was demonstrated. Because of its low cost, non-toxicity, the natural abundance of
iron
Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
, its excellent thermal stability, safety characteristics, electrochemical performance, and specific capacity (170
mA·h/
g, or 610
C/
g) it has gained considerable market acceptance.
The chief barrier to commercialization was its intrinsically low
electrical conductivity. This problem was overcome by reducing the particle size, coating the particles with conductive materials such as
carbon nanotubes, or both. This approach was developed by
Michel Armand
Michel Armand (born 1946) is a French scientist who is best known for helping with the invention of Lithium batteries.
Lithium batteries are electrochemical devices that are widely used as power sources. The history of their development has con ...
and his coworkers. Another approach by
Yet Ming Chiang's group consisted of
doping LFP with
cations
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by con ...
of materials such as
aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
,
niobium, and
zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...
.
Negative electrodes (anode, on discharge) made of petroleum coke were used in early lithium-ion batteries; later types used natural or synthetic graphite.
Specifications
![Lithium Iron Phosphate LiFePO4 Cells 700Ah in Parallel and Series and Busbar - 1](https://upload.wikimedia.org/wikipedia/commons/0/08/Lithium_Iron_Phosphate_LiFePO4_Cells_700Ah_in_Parallel_and_Series_and_Busbar_-_1.jpg)
* Cell voltage
** Minimum discharge voltage = 2.0-2.8 V
** Working voltage =
** Maximum charge voltage = 3.60-3.65 V
* Volumetric
energy density = 220
Wh/
L (790 kJ/L)
* Gravimetric energy density > 90 Wh/kg (> 320 J/g). Up to 160 Wh/kg
(580 J/g).
* Cycle life from 2,700 to more than 10,000 cycles depending on conditions.
[
]
Advantages and disadvantages
The LFP battery uses a lithium-ion-derived chemistry and shares many advantages and disadvantages with other lithium-ion battery chemistries. However, there are significant differences.
Resource availability
Iron and phosphates are very common in the Earth's crust. LFP contain neither nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
nor cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...
, both of which are supply-constrained and expensive. As with lithium, human rights and environmental concerns have been raised concerning the use of cobalt. Environmental concerns have also been raised regarding the extraction of nickel.
Cost
In 2020, the lowest reported LFP cell prices were $80/kWh (12.5Wh/$) .
A 2020 report published by the Department of Energy A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-re ...
compared the costs of large scale energy storage systems built with LFP vs NMC. It found that the cost per kWh of LFP batteries was about 6% less than NMC, and it projected that the LFP cells would last about 67% longer (more cycles). Because of differences between the cell's characteristics, the cost of some other components of the storage system would be somewhat higher for LFP, but in balance it still remains less costly per kWh than NMC.
Better ageing and cycle-life characteristics
LFP chemistry offers a considerably longer cycle life than other lithium-ion chemistries. Under most conditions it supports more than 3,000 cycles, and under optimal conditions it supports more than 10,000 cycles. NMC batteries support about 1,000 to 2,300 cycles, depending on conditions.
LFP cells experience a slower rate of capacity loss (a.k.a. greater calendar-life) than lithium-ion battery chemistries such as cobalt () or manganese spinel () lithium-ion polymer batteries
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 electrol ...
(LiPo battery) or lithium-ion batteries.
Viable alternative to lead-acid batteries
Because of the nominal 3.2 V output, four cells can be placed in series for a nominal voltage of 12.8 V. This comes close to the nominal voltage of six-cell lead-acid batteries. Along with the good safety characteristics of LFP batteries, this makes LFP a good potential replacement for lead-acid batteries in applications such as automotive and solar applications, provided the charging systems are adapted not to damage the LFP cells through excessive charging voltages (beyond 3.6 volts DC per cell while under charge), temperature-based voltage compensation, equalisation attempts or continuous trickle charging Trickle charging means charging a fully charged battery at a rate equal to its self-discharge rate, thus enabling the battery to remain at its fully charged level; this state occurs almost exclusively when the battery is not loaded, as trickle cha ...
. The LFP cells must be at least balanced initially before the pack is assembled and a protection system also needs to be implemented to ensure no cell can be discharged below a voltage of 2.5 V or severe damage will occur in most instances, due to irreversible deintercalation of LiFePO4 into FePO4.
Safety
One important advantage over other lithium-ion chemistries is thermal and chemical stability, which improves battery safety. is an intrinsically safer cathode material than and manganese dioxide spinels through omission of the cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...
, with its negative temperature coefficient
A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property ''R'' that changes when the temperature changes by ''dT'', the temperature coefficient α is def ...
of resistance that can encourage 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 ...
. The P– O bond in the ion is stronger than the Co– O bond in the ion, so that when abused (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. ...
ed, overheated, etc.), the oxygen atoms are released more slowly. This stabilization of the redox energies also promotes faster ion migration.
As lithium migrates out of the cathode in a cell, the undergoes non-linear expansion that affects the structural integrity of the cell. The fully lithiated and unlithiated states of are structurally similar which means that cells are more structurally stable than cells.
No lithium remains in the cathode of a fully charged LFP cell. In a cell, approximately 50% remains. is highly resilient during oxygen loss, which typically results in an exothermic reaction in other lithium cells. As a result, cells are harder to ignite in the event of mishandling (especially during charge). The battery does not decompose
Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ...
at high temperatures.
Lower energy density
The energy density (energy/volume) of a new LFP battery is some 14% lower than that of a new battery. Since discharge rate is a percentage of battery capacity, a higher rate can be achieved by using a larger battery (more ampere hours) if low-current batteries must be used. Better yet, a high-current LFP cell (which will have a higher discharge rate than a lead acid or battery of the same capacity) can be used.
Uses
Home energy storage
Enphase pioneered LFP home storage batteries for reasons of cost and fire safety, although the market remains split among competing chemistries. Though lower energy density compared to other lithium chemistries adds mass and volume, both may be more tolerable in a static application. In 2021, there were several suppliers to the home end user market, including SonnenBatterie and Enphase. Tesla Motors
Tesla, Inc. ( or ) is an American multinational automotive and clean energy company headquartered in Austin, Texas. Tesla designs and manufactures electric vehicles (electric cars and trucks), battery energy storage from home to grid- ...
continues to use NMC batteries in its home energy storage products, but in 2021 switched to LFP for its utility-scale battery product. According to EnergySage the most frequently quoted home energy storage battery brand in the U.S. is Enphase, which in 2021 surpassed Tesla Motors
Tesla, Inc. ( or ) is an American multinational automotive and clean energy company headquartered in Austin, Texas. Tesla designs and manufactures electric vehicles (electric cars and trucks), battery energy storage from home to grid- ...
and LG.
Vehicles
Higher discharge rates needed for acceleration, lower weight and longer life makes this battery type ideal for forklifts, bicycles and electric cars. 12V LiFePO4 batteries are also gaining popularity as a second (house) battery for a caravan, motor-home or boat.
Tesla Motors
Tesla, Inc. ( or ) is an American multinational automotive and clean energy company headquartered in Austin, Texas. Tesla designs and manufactures electric vehicles (electric cars and trucks), battery energy storage from home to grid- ...
currently uses LFP batteries in certain vehicles, including its Chinese-made Standard Range Models 3 and Y, and some Model 3 units in the United States beginning around August 2021. In October 2021, Tesla announced that all standard-range Models 3 and Y will begin using LFP battery chemistry.
In late 2021, Our Next Energy demonstrated a long range test of a Model S retrofitted with an LFP battery traveling for 752 miles on a single charge.
Solar-powered lighting systems
Single "14500" ( AA battery–sized) LFP cells are now used in some solar-powered landscape lighting
Landscape lighting or garden lighting refers to the use of outdoor illumination of private gardens and public landscapes; for the enhancement and purposes of safety, nighttime aesthetics, accessibility, security, recreation and sports, and s ...
instead of 1.2 V NiCd/NiMH NIMH may refer to:
*Nickel–metal hydride battery (NiMH), a type of electrical battery
*National Institute of Mental Health, an agency of the United States government
*National Institute of Medical Herbalists, a professional organisation in the Un ...
.
LFP's higher (3.2 V) working voltage lets a single cell drive an LED without circuitry to step up the voltage. Its increased tolerance to modest overcharging (compared to other Li cell types) means that can be connected to photovoltaic cells without circuitry to halt the recharge cycle. The ability to drive an LED from a single LFP cell also obviates battery holders, and thus the corrosion, condensation and dirt issues associated with products using multiple removable rechargeable batteries.
By 2013, better solar-charged passive infrared security lamps emerged. As AA-sized LFP cells have a capacity of only 600 mAh (while the lamp's bright LED may draw 60 mA), the units shine for at most 10 hours. However, if triggering is only occasional, such units may be satisfactory even charging in low sunlight, as lamp electronics ensure after-dark "idle" currents of under 1 mA.
Other uses
Some electronic cigarettes use these types of batteries. Other applications include marine electrical systems and propulsion, flashlights, radio-controlled model
A radio-controlled model (or RC model) is a model that is steerable with the use of radio control. All types of model vehicles have had RC systems installed in them, including ground vehicles, boats, planes, helicopters and even submarines and ...
s, portable motor-driven equipment, amateur radio equipment, industrial sensor systems and emergency light
An emergency light is a battery-backed lighting device that switches on automatically when a building experiences a power outage.
In the United States, emergency lights are standard in new commercial and high occupancy residential buildings, ...
ing.
See also
* 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. ...
* List of battery sizes
This is a list of the sizes, shapes, and general characteristics of some common primary and secondary battery types in household, automotive and light industrial use.
The complete nomenclature for a battery specifies size, chemistry, termina ...
* List of electric-vehicle-battery manufacturers
* Comparison of commercial battery types This is a list of commercially-available battery types summarizing some of their characteristics for ready comparison.
Common characteristics
Cost in USD, adjusted for inflation.
Typical. See for alternative electrode materials.
Rechargeable ...
* Lithium-titanate battery
The lithium-titanate or lithium-titanium-oxide (LTO) battery is a type of rechargeable battery which has the advantage of being faster to charge than other lithium-ion batteries but the disadvantage of having a much lower energy density.
Uses
...
* 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 ca ...
* Lithium polymer battery
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 ...
* Nanowire battery
* Phosphate
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phosph ...
* Power-to-weight ratio
* Solid-state battery
A solid-state battery is a battery technology that uses solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries.
While solid electrolytes were first discovered ...
* Super-iron battery
* Blade battery
Blade battery is a type of lithium iron phosphate (LFP) battery for electric vehicles designed and manufactured by FinDreams Battery, a subsidiary of Chinese manufacturing company BYD.
The Blade Battery is most commonly a 96 cm long and ...
* XPeng
Guangzhou Xiaopeng Motors Technology Co Ltd (), doing business as XPeng Motors (), commonly known as XPeng, is a Chinese electric vehicle manufacturer. The company is headquartered in Guangzhou, Guangdong, with offices in Mountain View, Califor ...
References
{{emerging technologies, energy=yes
Lithium-ion batteries
Phosphates
Vanadium
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