Hierarchical MnO@C Hollow Nanospheres for Advanced\nLithium-Ion Battery Anodes

Abstract

Rational morphology\ndesign is of great significance for achieving\nsuperior cycling performance and rate capability for lithium-ion batteries.\nHere we designed and fabricated hierarchical MnO@C hollow nanospheres\n(HNSs) consisting of nitrogen-doped carbon outer shells and MnO hollow\nspheres composed of ultrathin MnO nanosheets. The hierarchical hollow\nstructures provided abundant active sites for lithium storage while\naccommodating the volume change, leading to high reversible capacity\nand rate performance. The graphitic carbon shells improved the electrical\nconductivity and restricted the volume expansion of MnO, which helped\nto achieve enhanced cycling stability and improved rate capability.\nWhen used as an anode material for lithium-ion batteries, the hierarchical\nMnO@C HNSs retained a capacity of 839 mAh g^–1 after\n900 cycles at 1 A g^–1. The excellent electrochemical\nperformance of these MnO@C HNSs may be attributed to the synergetic\neffects of the hierarchical hollow structure and the conductive carbon\ncoating layer. This work provided a controllable approach toward hierarchical\nhollow structures of desired hybrid materials for high-performance\nelectrodes.