Enhancing the operation stability of lithium-rich layered oxide Li1.2Ni0.2Mn0.6O2 by synergistic pinning effect and interface reconstruction for high-energy-density lithium-ion batteries

Abstract

Lithium-rich manganese-based layered oxides are considered to be promising cathode materials for next-generation lithium-ion batteries (LIBs). However, their practical application is hindered due to both the rapid capacity attenuation and the unsatisfactory rate capability. In this work, to overcome these problems, layered oxide Li1.2Ni0.2Mn0.6O2 (LNMO) is modified via La3+ doping and perovskite type LaMnO3 coating layer, meanwhile, interface layer Li2MnO3 with monoclinic structure is formed between the doped-La3+ Li1.2Ni0.2Mn0.6O2 and LaMnO3 coating layer. The 0.02 wt% La modified Li1.2Ni0.2Mn0.6O2 can deliver much higher rate capability and cyclic stability than original LNMO, attributed that the LaMnO3 coating layer can not only isolate La-doped LNMO from the electrolyte to reduce the dissolution of manganese ions but also can reduces the polarization of electrode interface via inhibiting the continuous growth of SEI during the cycle. Besides, La3+ doping plays a pinning effect role in enhancing the structural stability of LNMO.