Lithium iron phosphate battery (LiFePO ₄ , LFP, “lifer”)  is a type of lithium-ion battery (the charge is carried by lithium ions ) , in which the cathode is made of lithium ferrophosphate ( orthophosphoric acid salt , LiFePO ₄ ) , and the anode is made of graphite on a copper foil substrate . ^[1] [2] Due to lower cost, safety, low toxicity, long service life,… LFP batteries are widely used in vehicles, stationary batteries and backup power. LFP batteries do not contain cobalt.

As of September 2022, the market share of LFP batteries for electric vehicles reached 31%, and of this, 68% were from Tesla and Chinese electric vehicle manufacturer BYD alone. Chinese manufacturers currently have a near-monopoly on the production of LFP batteries, however, with patents expiring in 2022, demand and production of cheaper mass-produced batteries of this type are expected to increase.

· _LiFePO4 was first discovered in 1996 by Professor John Goodenough of the University of Texas , as a cathode for a lithium-ion battery . This material was notable for the fact that, in comparison with traditional LiCoO ₂ , it has a significantly lower cost, is less toxic and more heat-resistant. The main disadvantage was that it had a smaller capacity .

· Until 2003, this technology practically did not develop, until the company A123 Systems took it up . The history of A123 Systems began in the laboratory of Professor Jiang Ye-Ming from the Massachusetts Institute of Technology (MIT) in late 2000. At that time, Jiang was working on creating a battery based on the self-reproduction of the structure of a colloidal solution under certain conditions. However, serious difficulties arose on this front of work, and when research stalled in 2003, Jiang's team began researching lithium iron phosphate batteries. Global corporations such as Motorola , Qualcomm and Sequoia Capital became investors in the created company .

· Characteristics [ edit | edit code ]

· Specific energy density: 90-160 W • h / kg (320-580 kJ / kg )

· Volumetric energy density: 220–350 W • h / dm ³ (790 kJ / dm ³ )

· Volumetric density of the structure: 2 kg / dm ³

· The number of charge-discharge cycles before losing 20% of the capacity: 2000-7000 ^[3] (the resource strongly depends on the charge and discharge current, so at a current of 0.25C the resource at a 100% depth of discharge exceeds 6000 cycles, at a current of 1C it drops to 3000. The resource also depends on the discharge depth: if at a current of 1C and 100% discharge depth the resource is 3000 cycles, then at 80% it is 4500, and at 60% it is already 10000 cycles ^[4] ).

· Shelf life: up to 15 years ^[3]

· Self-discharge at room temperature: 3-5% per month

· Voltage

o maximum per cell: 3.65 V (fully charged)

o midpoint: 3.3 V

o minimum: 2 V (fully discharged)

o working: 3.0-3.3 V

o Minimum operating voltage (discharge): 2.5 V

· Specific power : >6.6 W / g (discharge current 60C)

· Operating temperature range during discharge: from −30 °C to +55 °C; when charging: 0 °C to 40 °C.