A lithium-ion flow battery is a

flow battery A flow battery, or redox flow battery (after reduction–oxidation), is a type of electrochemical cell where chemical energy is provided by two chemical components dissolved in liquids that are pumped through the system on separate sides of a ...

that uses a form of lightweight lithium as its

charge carrier In physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. The term is used ...

. The flow battery stores energy separately from its system for discharging. The amount of energy it can store is determined by tank size; its

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 ...

is determined by the size of the reaction chamber. Dissolving a material changes its chemical behavior significantly. Flow batteries suspend grains of solid material in a liquid, which preserves its characteristics, making lithium's high energy density available to flow systems.

Lithium polysulfide

One device uses dissolved

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 ...

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 whi ...

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 ...

metal 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 is ...

and an

organic solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for p ...

as the electrolyte. Officially "membraneless", it uses a coating to separate

from

. It uses a single tank and pump and reacts the LiS with lithium to produce power. The device operated for more than 2000 cycles without substantial degradation. When discharging, the lithium polysulfide absorbs lithium ions; releasing them when charging. The demonstration device yielded

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 97 Wh/kg and 108 Wh/L with a 5M catholyte.

LiFePO₄

Reversible delithiation/lithiation of was successfully demonstrated using

ferrocene Ferrocene is an organometallic compound with the formula . The molecule is a complex consisting of two cyclopentadienyl rings bound to a central iron atom. It is an orange solid with a camphor-like odor, that sublimes above room temperature, a ...

derivatives. This device keeps the energy storage materials stored in separate tanks. The liquids remain stationary during operation. The device incorporated a lithium-ion permeable membrane.

Lithium iodine

A cathode-flow lithium-iodine (Li–I) battery uses the triiodide/iodide (⁻/I⁻) redox couple in aqueous solution. It has energy density of 0.33 kWh/kg because of the solubility of LiI in aqueous solution (≈8.2M) and its power density of 130 mW/cm² at a current rate of 60 mA/cm², 328 K. In operation, the battery attains 90% of the theoretical storage capacity,

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 ...

of 100%±1% in 2–20 cycles, and cyclic performance of >99% capacity retention for 20 cycles, up to total capacity of 100 mAh.

LiTi₂(PO₄)₃–LiFePO₄

A semi-solid cell based on the couple utilizes fluid electrodes that are electronically conductive. Simultaneous

advection In the field of physics, engineering, and earth sciences, advection is the transport of a substance or quantity by bulk motion of a fluid. The properties of that substance are carried with it. Generally the majority of the advected substance is al ...

and electrochemical transport separates flow-induced losses from those due to underlying side reactions. Plug flow is used to achieve energy efficiency with non-Newtonian flow electrodes.

References

External links

* {{Cite journal , last1 = Wang , first1 = Y. , last2 = He , first2 = P. , last3 = Zhou , first3 = H. , doi = 10.1002/aenm.201200100 , title = Li-Redox Flow Batteries Based on Hybrid Electrolytes: At the Cross Road between Li-ion and Redox Flow Batteries , journal = Advanced Energy Materials , volume = 2 , issue = 7 , pages = 770 , year = 2012 , s2cid = 96707630 Flow batteries Lithium-ion batteries