General formation of Mn-based transition metal oxide twin-microspheres with enhanced lithium storage properties

Abstract

In this investigation, we designed a general method to manipulate the controlled preparation of Mn-based transition metal oxide materials with the structure of hierarchical twin-microspheres. Initiated by a precursor solvothermal synthesis of metal carbonate twin-microspheres, the formation of hierarchical twin-microspheres of metal oxides was finalized by thermal annealing in laboratory air. The method allows one to prepare binary and ternary hierarchical twin-microspheres constructed by primary ultrathin nanoparticles. By applying the respective metal salts in the synthesis, six oxide species, including Mn₃O₄, CoMn₂O₄, ZnMn₂O₄, Ni_xMn_3−xO₄, Cu_xMn_3−xO₄, and Fe_xMn_3−xO₄, have been reported herein in order to draw common features via oriented-attachment. Concerning the workability, CoMn₂O₄ twin-microspheres are evaluated as electrode materials for lithium-ion batteries. As expected, the CoMn₂O₄ twin-microspheres exhibit excellent rate performance and impressive cycling stability due to their unique assembled architecture and probably synergetic effects of different metal ions.