LiFePO4

LiFePO4, or lithium iron phosphate, is a cathode material used in lithium-ion batteries. It features an olivine crystal structure that contributes to high thermal stability and improved safety compared with many cobalt-containing cathodes. The material is also known by the acronym LFP.

In rechargeable cells, LiFePO4 provides a nominal voltage of about 3.2 to 3.3 volts and a theoretical capacity of around 170 mAh per gram. Practical cell capacities typically fall in the 150–160 mAh/g range. Because of its lower operating voltage and lower specific capacity, LiFePO4-based cells generally offer lower energy density (both gravimetric and volumetric) than cobalt-based chemistries, with energy densities commonly around 90–120 Wh/kg at the cell level, depending on design and packaging. The material is noted for good cycle life, often enduring thousands of cycles with modest capacity fade when properly managed.

Advantages of LiFePO4 include high thermal stability, enhanced safety (reduced risk of thermal runaway), broad operating temperature range, and relatively low material cost due to the abundance of iron and phosphate. These attributes make LFP attractive for applications where safety, longevity, and cost are prioritized over maximum energy density.

Disadvantages center on its lower energy density and lower cell voltage compared with some other lithium-ion chemistries, which can limit range in energy-constrained applications. Power performance is generally adequate but can be less competitive at very high discharge rates without optimization.

Applications for LiFePO4 span electric vehicles, stationary energy storage systems, power tools, and grid storage projects, where safety and long cycle life are valued. The technology has seen widespread adoption since the early 2000s and is produced by multiple suppliers worldwide.