Microwave-assisted solvothermal synthesis of mesoporous rod-like manganese oxalate as a high-performance anode for lithium-ion batteries

Manganese oxalate rods were prepared by a microwave-assisted solvothermal route, and the microstructure evolution was investigated. When the temperature rises from room temperature to 220 °C, α-MnC2O4·2H2O cubes are transformed into rods by the dissolution–recrystallization. With the extension of microwave reaction time, the morphology evolution of rods follows the Ostwald ripening mechanism, and the aspect ratio, specific surface area, and pore volume first increase and then decrease. After removing the crystalline water, α-MnC2O4·2H2O rods are converted into orthogonal MnC2O4 rods with more abundant mesoporous channels. Mesoporous MnC2O4 rods prepared at 220 °C for 10 min deliver a high reversible capacity of 949 mAh/g after 500 cycles at 5 A/g, exhibiting superior performance. Therefore, microwave reaction time can tune the microstructure and alter the electrochemical properties of MnC2O4. The findings on the microstructure evolution provide insights into the controllable synthesis of manganese oxalate, ultimately enhancing its performance.