Synthesis and research of MnO2–NiO composite as lithium-ion battery anode using spent Zn–Mn batteries as manganese source

Abstract

In this work, we have successfully synthesized porous flower-like MnO2–NiO anode material for lithium ion batteries by facile hydrothermal method using the manganese source that is recovered from spent Zn–Mn batteries through hydrometallurgy recycling technology. Scanning electron microscopy (SEM) reveals that such an architecture provides short paths for lithium diffusion and large material/electrolyte contact area. The electrochemical measurements exhibit that the initial discharge capacity of MnO2–NiO composite is 2981 mAh·g−1 at a current density of 100 mA g−1 and retains at 502 mAh·g−1 after 100 cycles, much higher than that of pure MnO2. Even at a high current rate of 400 mA g−1, the specific capacity still remains at 297 mAh·g−1 after 50 cycles. The electrode exhibits excellent cycling performances and high capacity. Furthermore, the lithiation and delithiation processes of MnO2–NiO anode material have been studied in detail by X-ray diffraction characterization. We found that during the lithiation process, MnO2 reacts with lithium ions to form the intermediate product of Mn2O3, which is further reduced to Mn metal. NiO directly reacts with lithium ions to form Ni metal.