General Synthesis of MnOx (MnO2, Mn2O3, Mn3O4, MnO) Hierarchical Microspheres as Lithium-ion Battery Anodes

Four type of MnOx (MnO2, Mn2O3, Mn3O4, MnO) hierarchical microspheres assembled by rod-like building blocks are synthesized by a facile hydrothermal process with/without a consequent calcination. The morphology and structure of these hierarchical microspheres are confirmed by XRD, SEM, TEM, HRTEM, XPS and BET measurements. The electrochemical properties of the four hierarchical microspheres are investigated in terms of cycling stability and rate capability. Specific capacities of 240, 396, 271 and 810 mAh g(-1) can be achieved after 100 cycles at 0.5C for MnO2, Mn2O3, Mn3O4 and MnO, respectively. Even at a high rate of 2C, MnO microspheres can still deliver a reversible capacity of 406 mA h g(-1). Their superior electrochemical properties might be attributed to the secondary nanostructure in the MnOx microspheres, which could effectively shorten the diffusion pathway of Li+, tolerate the structural stress caused by Li+ insertion/extraction, reduce the side reactions with electrolyte, and restrain the self-aggregation of nanomaterials. (C) 2015 Elsevier Ltd. All rights reserved.