Excellent cyclic performance of electrolytic MnO2 in Li/MnO2 rechargeable batteries

The electrolytic MnO2 particles with α∙γ-MnO2 is successfully prepared using one-step acid constant current electrodeposition method. Scanning electron microscope, N2 adsorption/desorption method and X-ray diffraction are employed for the material characterization. Scanning electron microscope result shows that the diameter of MnO2 particle is about 350–500 nm. A lot of mesoporous exist in the as-prepared MnO2 particles, which exhibit high specific surface area and can provide significantly more electrochemical active sites for the redox reaction. The as-prepared MnO2 particles as cathode in rechargeable Li/MnO2 battery displays high discharge capacity of 202 mAh g−1 in the 1st cycle at a current density of 46 mA g−1, and its discharge capacity retention ratio can achieve 82% over 100 cycles. The discharge capacities of the 100th cycle are 152, 127 and 114 mAh g−1 at different current densities of 151, 350 and 755 mA g−1, respectively, indicating excellent rate capability. The promising electrochemical performance of α∙γ-MnO2 can make researchers focus again on using metal oxide as the cathode materials in the rechargeable Li-ion batteries.