“…Nonetheless, the above-mentioned electrochemically inactive layer causes lower capacity and Li + diffusion. Therefore, electron conducting materials such as carbon and graphene [50], lithium ion conductors such as Li 2 O· 2B 2 O 3 [51], Li 3 VO 4 [42] and Li 2 ZrO 3 [52,53], have been developed as coating materials for Ni-based cathode materials. Some lithium based materials have also been used to react with residual impurities on the surface of Ni-rich cathode materials and form a uniform coating layer on the bulk surface at the same time [54][55][56].…”