Effective regulation of Li2MnO3-like single-component in high-nickel Li-rich layered oxides by trace Sb doping for remarkable performance improvement

Abstract

The exact roles of LiNiO2-like R—3m and Li2MnO3-like C2/m components in performance of Li-rich layered oxides (LLOs) still remain elusive which is precluded predominantly by simultaneous modifications of or doping of alien elements into two components normally. Herein, we propose a strategy of employing trace Sb to regulate the Li2MnO3-like C2/m single component (SCR) only to effectively stabilize the structure of High-nickel Li-rich layered oxides based on the far lower doping potential of Sb into the Li2MnO3-like C2/m phase than that into the LiNiO2-like phase. The SCR realized using a facile expanded graphite template-sacrificed approach significantly improves the lattice oxygen reversibility and restrains structural degradation via lowering the unhybridized O 2p orbitals. This enables an extraordinarily steady voltage with a decay rate of 0.87 mV per cycle, a capacity retention as high as ∼85.5% after 300 cycles at 1 C and thus a steady energy density against cycling. This work opens a new avenue for regulating the individual C2/m or R—3m phases to enhance the performance of LLOs via alien element doping and provides the possibility of exploring the mechanisms of single component influencing the performance.