Facile template-free synthesis of 3D porous MnO/C microspheres with controllable pore size for high-performance lithium-ion battery anodes

Abstract

3D porous MnO/C anode materials with controllable pore size are rationally designed and synthesized by a facile template-free strategy. The Mn_xZn_1–xCO₃ (x = 1, 2/3, 1/2 and 1/3) precursors were prepared by an ultrasonic-assisted co-precipitation method, and then heated with glucose in a reducing atmosphere to obtain a series of MnO/C microspheres through topochemical conversion. These MnO/C microspheres consist of nanosized primary particles and have interconnected pore architectures with high specific surface areas of up to 111.4 m² g⁻¹. Adjusting the Zn/Mn molar ratio of Mn_xZn_1–xCO₃ can easily tune the pore size of the MnO/C materials from 14.9 nm to 31.8 nm. Electrochemical performances of the MnO/C materials were found to be strongly correlated with their porous structures. The MnO/C material with optimized pore size exhibits a high reversible capacity (846 mA h g⁻¹ at 100 mA g⁻¹), superior rate capability (406 mA h g⁻¹ at 3200 mA g⁻¹) and excellent cycling stability. This strategy can be extended to prepare other candidate electrode materials.