Hierarchical MnMoO4@nitrogen-doped carbon core-shell microspheres for lithium/potassium-ion batteries

Abstract Transition metal oxides (TMOs) are deemed as promising next-generation anode materials for alkali-ion batteries owing to their high energy density. However, the structures of the TMOs electrode materials are destroyed due to the huge volume changes during charging/discharging, so that the batteries cannot provide a long cycle life. Herein, a unique hierarchical MnMoO4@nitrogen-doped carbon (MnMoO4@NC) core-shell microspheres are synthesized as an advanced electrode material for lithium-ion batteries (LIBs) and potassium-ion batteries (PIBs). Specifically, the semi-hollow microspheres structures of MnMoO4 formed by self-assembly of nanoparticles can improve its utilization efficiency and the speed of ion transfer. Moreover, the uniform nitrogen-doped carbon layer not only improves the structural stability of MnMoO4 but also enhances the electrical conductivity of the overall composite. The resultant MnMoO4@NC as an anode for LIBs delivers 817 mAh g−1 after 800 cycles at 1 A g−1, and for PIBs remains 95 mAh g−1 over 400 cycles at 0.5 A g−1.