Modulating the bonding properties of Li2MoO3 via non-equivalent cationic doping to enhance its stability and electrochemical performance for lithium-ion battery application

Abstract Li2MoO3 (LMO) is a promising stabilization block for constructing high performance lithium-rich layered oxides. However, its poor electronic conductivity, surface instability in air, and capacity degradation are drawbacks for the application. To solve these issues, non-equivalent Nb5+ dopants were introduced into the LMO lattice. Density functional theory (DFT) calculations combined with experimental characterizations have confirmed that Nb5+ doping not only enhances the Mo–O bonds of LMO but also reduces its band gap and further suppresses the oxidation of surface Mo4+, leading to a much-improved lattice and surface stabilities. Therefore, the electrochemical performances of LMNO are improved obviously. The initial discharge capacities of LMO, LMNO-0.01, LMNO-0.02, and LMNO-0.03 are 232.6, 234.7, 251.6, and 246.3 mAh·g−1, respectively. LMNO-0.02 exhibits the best performance, and its specific capacities at the 1st and 100th cycles reach 144.13 and 72.06 mA g−1 under a 3C charging rate and a 5C discharging rate. Our results have demonstrated that non-equivalent cationic doping is an effective strategy to modulate the bonding characteristics of LMO and therefore to improve its electrochemical performance.