Rapid Microwave Synthesis of Self-Assembled Hierarchical Mn₂O₃ Microspheres as Advanced Anode Material for Lithium Ion Batteries

Graphical abstract: Synopsis: Self-assembled hierarchical Mn₂O₃ microspheres is synthesized as anode material for lithium ion battery through rapid microwave hydrothermal processes within 30 minutes. All the raw materials and products are under the principle of environmental protection. - Highlights: • Hierarchical Mn₂O₃ microsphere is obtained by rapid microwave hydrothermal synthesis. • Large specific surface area with mesoporous is characterized. • High specific capacity of 921.6 mAh g⁻¹ is reached at 200 mA g⁻¹. • Continual enhancement of interface Li-storage brings an abnormal high capacity. • High capacity of 525 mAh g⁻¹ is obtained at 1000 mA g⁻¹ after 500 cycles. - Abstract: Rapid microwave hydrothermal synthesis is carried out to obtain hierarchical Mn₂O₃ microsphere through a self-assembled process within 30 minutes. All the raw materials used is nontoxicity without any template or polymer and the side-products are all small molecules which abide by the pricnciple of environmental protection. After the following solid state reaction, the as-prepared Mn₂O₃ powders can still keep the hierarchical morphology of micro sphere which is consisted of small primary particles and secondary slices. The sample obtained at 600 °C with high crystallinity, large specific surface area and mesoporous exhibits best electrochemical performances. High specific capacity of 921.6 mAh g⁻¹ could be reached at a current density of 200 mA g⁻¹. An interesting phenomenon with abnormal capacity increasing appears which could be ascribed to the continual enhancement of interface Li-storage. Thus, high specific capacity of about 525 mAh g⁻¹ is obtained at high current density of 1000 mA g⁻¹ after 500 cycles. Furthermore, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are performed to further study the hierarchical Mn₂O₃ anode material. It is revealed that such rapid microwave synthesis without any contamination is considered as a promising way to obtain hierarchical manganese oxides as anode material for applications.