pH-Buffer Contained Electrolyte for Self-Adjusted Cathode-Free Zn-MnO2 Batteries with Coexistence of Dual Mechanisms

Aqueous Zn-MnO2 batteries have received much attentions for large-scale applications because of high safety and low cost. However, the energy storage mechanisms of Zn-MnO2 system are still in dispute. Herein, a cathode-free Zn-MnO2 battery is provided with the coexistence of dual mechanisms in mild acidic environment, in which the decisive guiding effect of the pH value in electrolyte on the mechanism is deeply investigated. On this basis, acetic acid (HAc) is used as a buffering additive to effectively suppress the fluctuation phenomenon during the operation, hence achieving the self-adjust mechanism. The assembled soft package battery possesses a long lifetime of 2000 cycles with the Coulombic efficiency of 99.6%, improved high-loading performance and rate capability. A new idea is provided for the exploration of energy storage mechanism of Zn-MnO2 battery as well as a guidance on the optimization strategies especially the battery construction.

Automated summary

This study investigates a cathode-free Zn-MnO2 battery with dual mechanisms in a mild acidic environment, emphasizing the decisive effect of pH value in the electrolyte on the mechanisms. Through the use of acetic acid as a buffering additive, the fluctuation phenomenon during operation is effectively suppressed, achieving a self-adjusting mechanism and improving battery performance.