Lithium iron phosphate

Lithium iron phosphate (LiFePO
4), also known as LFP, is a compound used in lithium iron phosphate batteries (related to Li-Ion batteries). It is targeted for use in power tools, electric vehicles and solar energy installations. It is also used in OLPC XO education laptops.

Most lithium batteries (Li-ion) used in 3C (computer, communication, consumer electronics) products use cathodes of other lithium molecules, such as lithium cobalt oxide (LiCoO₂) lithium manganese oxide (LiMn₂O₄) and lithium nickel oxide (LiNiO₂). The anodes are generally made of carbon.

The annual production of lithium carbonate available to the automotive industry is estimated at only 30,000 tonnes in 2015. While a natural lithium iron phosphate mineral exists (triphylite) issues with purity and structure make it unsuitable for use in batteries.

LiMPO₄

LiFePO
4 is a member of the olivine group, which has a general chemical formula of LiMPO_4, where M refers to any metal, including Fe, Co, Mn and Ti. The first commercial LiMPO₄ was C/LiFePO
4 and therefore, people refer to the whole group of LiMPO₄ as lithium iron phosphate, LiFePO
4. However, more than one olivine compound may be used as a battery's cathode material. Olivine compounds such as AyMPO₄, Li₁-xMFePO₄, and LiFePO
4-zM have the same crystal structures as LiMPO₄ and may replace in a cathode. All may be referred to as “LFP”.

Lithium iron phosphate battery

The lithium iron phosphate (LiFePO
4) battery, also called LFP battery (with "LFP" standing for "lithium ferrophosphate"), is a type of rechargeable battery, specifically a lithium-ion battery, which uses LiFePO
4 as a cathode material. LiFePO
4 batteries have somewhat lower energy density than the more common LiCoO
2 design found in consumer electronics, but offers longer lifetimes, better power density (the rate that energy can be drawn from them) and are inherently safer. LiFePO
4 is finding a number of roles in vehicle use and backup power.

History

LiFePO
4 is a natural mineral of the olivine family (triphylite). Its use as a battery electrode was first described in published literature by John Goodenough's research group at the University of Texas in 1996, as a cathode material for rechargeable lithium batteries. Because of its low cost, non-toxicity, the natural abundance of iron, its excellent thermal stability, safety characteristics, electrochemical performance, and specific capacity (170 mA·h/g, or 610 C/g) it gained some market acceptance.