Li(Ni,Co)PO4 as cathode materials for lithium batteries: Will the dream come true?

Among the lithium-transition metal phosphates, LiFePO4 is an important cathode material both for Li-ion and Li-metal batteries, due to its very good thermal stability, safety, low cost, excellent cycling life, and rate capability [1]. Its practical capacity is close to the theoretical limit (170 mAh g−1) but the voltage is only 3.5 V vs. Li+/Li. The quest for higher energy density has led to consider the replacement of Fe by Co or Ni, which would raise the working potential to 4.8 and 5.1 V, respectively. The aim of the present work is to review the recent progress and to determine the possibility that these materials will be viable as commercial cathode materials for future Li batteries.