Effects of graphite contents and microstructures on the cathode performances of alkaline Zn-MnO2 batteries

As one of the most successful aqueous zinc-based batteries, the alkaline Zn-MnO 2 batteries (AZMBs) suffer from the low utilization of MnO 2 . This work proposes a simple approach to address this issue by optimizing the graphite contents and microstructures in the cathode. It is found that the cathode of AZMB containing 9 wt% graphite exhibits the best electrochemical performances, achieving the discharge capacities of 240.6 mAh and 196.25 mAh at 10 and 25 mA, increasing by 7.7 % and 9.0 % compared to that of the commercial AZMBs, respectively. Additionally, by adopting the fully-expanded graphite with large specific surface area and thin thickness, the discharge capacities of AZMB increase by 8.7 % and 8.8 % at 10 and 25 mA, compared to that of the commercial AZMBs, respectively. The improving discharge properties of AZMBs with proper graphite content and microstructure can be ascribed to the high conversion rate of MnO 2 into the discharge product of MnOOH due to the improved conductive network. This work provides a valuable insight for the development of the aqueous Zn-based batteries.