 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, 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.