Copper Doped Hollow Structured Manganese Oxide Mesocrystals with Controlled Phase Structure and Morphology as Anode Materials for Lithium Ion Battery with Improved Electrochemical Performance

Abstract

We develop a facile synthesis route to prepare Cu doped hollow structured manganese oxide mesocrystals with controlled phase structure and morphology using manganese carbonate as the reactant template. It is shown that Cu dopant is homogeneously distributed among the hollow manganese oxide microspherical samples, and it is embedded in the lattice of manganese oxide by substituting Mn³⁺ in the presence of Cu²⁺. The crystal structure of manganese oxide products can be modulated to bixbyite Mn₂O₃ and tetragonal Mn₃O₄ in the presence of annealing gas of air and nitrogen, respectively. The incorporation of Cu into Mn₂O₃ and Mn₃O₄ induces a great microstructure evolution from core–shell structure for pure Mn₂O₃ and Mn₃O₄ samples to hollow porous spherical Cu-doped Mn₂O₃ and Mn₃O₄ samples with a larger surface area, respectively. The Cu-doped hollow spherical Mn₂O₃ sample displays a higher specific capacity of 642 mAhg^–1 at a current density of 100 mA g^–1 after 100 cycles, which is about 1.78 times improvement compared to that of 361 mA h g^–1 for the pure Mn₂O₃ sample, displaying a Coulombic efficiency of up to 99.5%. The great enhancement of the electrochemical lithium storage performance can be attributed to the improvement of the electronic conductivity and lithium diffusivity of electrodes. The present results have verified the ability of Cu doping to improve electrochemical lithium storage performances of manganese oxides