Study of Ni-dopped MnCo₂O₄ Yolk-Shell Submicron-spheres with Fast Li⁺ Intercalation Pseudocapacitance As An Anode for High-Performance Lithium Ion Batteries

Spinel Ni-dopped MnCo₂O₄ powder with fast Li⁺ intercalation pseudocapacitance is prepared from transition metal carbonates of Ni, Co and Mn as precursors through a solvothermal synthesis followed by an annealing treatment. As-made products are nanovoids submicron-spheres (the diameter is 500 nm–700 nm) with an obvious yolk-shell structure and uniform elements distribution. As an anode material with fast Li⁺ intercalation pseudocapacitance for lithium-ion battery (LIB), the Ni-dopped MnCo₂O₄ submicron-spheres exhibit an impressively first discharge efficiency (70%) and outstanding large-current cycling performance. The excellent electrochemical performance is closely ascribed to Li⁺ intercalation pseudocapacitance and the yolk-shell structure, which can effectively prevent the particles from being pulverized, and alleviate the volume changes of particles during the cycling process. In addition, the doping of Ni metal element to MnCo₂O₄ greatly enhances the electrochemical stability of MnCo₂O₄, due to the complementarities and synergies between the three metallic elements during the process of Li insertion or extraction reactions.