Advancing High-Safety Energy Storage: Trade-Off between Mass Loading and Specific Capacity of Manganese-Based Cathode in Zinc-Ion Batteries

Abstract

Water based zinc ion batteries have become a promising alternative to lithium-ion batteries due to their higher safety and environmental friendliness. Although manganese dioxide positive electrode has advantages in voltage, cost, and ecological friendliness, its cycling stability, actual capacity, and conductivity still have shortcomings. In addition, the impact of positive electrode material loading on capacity is also a key challenge in the actual research and development of zinc ion batteries. Research has shown that increasing the positive electrode load to improve surface capacity often leads to a decrease in specific capacity due to ion diffusion delay and electron transport obstruction, particularly under high-rate conditions. This study compared manganese-based cathodes with different loading levels (10.864 mg/cm ²and 15.880 mg/cm ²) and found that low loading electrodes maintained excellent rate performance (such as a capacity of 60 mAh/g at a current density of 1 A/g), while high loading electrodes experienced capacity degradation due to transmission bottlenecks. This result indicates that optimizing electrode design to balance load and kinetic efficiency will strongly promote the development of high-energy density zinc ion batteries.