Spinel Mn_(1.5)Co_(1.5)O4 core-shell microspheres as Li-ion battery anode materials with a long cycle life and high capacity

摘要

Transition metal oxides are important functional materials that have gained enormous research interest in recent years. In this work, porous cubic manganese cobalt spinel Mn_(1.5)Co_(1.5)O4 core-shell microspheres were first prepared via a urea-assisted solvothermal route followed by pyrolysis of the carbonate precursor. The microsphere is composed of the shell of 400 nm thickness and the core with a 2.5 μm diameter. Nitrogen sorption isotherms show that this structure possesses a high surface area of 27.0 m~2 g~(-1) with an average pore diameter of 30 nm. Compared with a simple spherical nanopowder, such a core-shell like porous structure is expected to improve the electrochemical performance, due to its higher resistance against separation or isolation during the electrochemical reaction. The as-prepared Mn_(1.5)Co_(1.5)O4 core-shell microspheres show an excellent cyclic performance at high current density with more than 90% capacity retention in a testing range of 300 cycles when used as an anode material for lithium ion batteries (LIBs), which can be attributed to the appropriate pore size and unique core-shell structures. Therefore, the Mn_(1.5)Co_(1.5)O4 core-shell microspheres prepared by the present synthetic route could be identified as a potential anode candidate for the near future development of LIBs.