Ni/Li antisite induced disordered passivation layer for high-Ni layered oxide cathode material

Abstract

High-Ni layered oxides are the next-generation cathodes owing to their capability to provide high capacity at a low cost. However, oxygen loss, transition metal (TM) dissolution, and irreversible phase transition often result in surface reconstruction, forming a rocksalt phase that results in poor electrochemical performance. Herein, a Li/Ni antisite induced disordered passivation layer is introduced on LiNi0.94Co0.03Mn0.03O2 by dual doping of Ta and Al. The ultrathin disordered layer is electrochemically active to improve the electron and ionic conductivities, stabilize lattice oxygen and alleviate the TM dissolution and irreversible phase transition. Therefore, it exhibits superior cycling stability (90.09% retention at 0.5 C between 2.7–4.3 V), robust rate capability, and improved Li+ diffusivity. First-principle calculations also confirm the outstanding structural stability of the disordered layered structure ascribed to the strong covalency of Ta-O and Al-O providing extra electrons to the oxygen atom, forming a robust oxygen framework. Hence, the synergistic effect of Ta and Al co-doping with antisite-induced disordered structure is a constructive approach for the commercialization of high-Ni layered oxide cathodes.