La Doping LiNiO2 Cathode to Immobilize the Lattice Oxygen for Highly Stable Lithium-Ion Batteries

Abstract

LiNiO₂ (LNO) with a high theoretical capacity and entirely free of cobalt has aroused much attention as a promising cathode material for lithium-ion batteries (LIBs). The rapid capacity decay, however, obstructs its commercialization. We first propose a strategy of La lattice-doping in the LNO (La-LNO) as a high-stability cathode for LIBs. Density-functional theory calculations suggest that the La dopant occupies the Ni-sites to stabilize the lattice oxygen due to a strengthening of the transition metal–oxygen bonds and mitigation of the charge compensation. La lattice-doped LNO cathode materials were fabricated successfully and had a specific capacity of 159.6 mAh g^–1 after 100 cycles at 1 C with a capacity retention of 94.2% and a voltage retention of 99.9%. Atomic characterization reveals that La-LNO effectively inhibits the oxygen release and phase transformation during the cycling process. Our strategy provides leading guidance for designing practical high-performance LNO cathode materials for advanced LIBs.