Activating High-Loading Cathodes Using Percolative Graphite in Rechargeable Alkaline Zn-MnO₂ Batteries

Due to the inherently insulating nature of MnO₂, the performance of rechargeable alkaline Zn-MnO₂ batteries is critically influenced by the conductive framework within the cathodes. Conventional approaches to achieving a percolating network in thick MnO₂ cathodes typically involve either large quantities of low-surface-area graphite or employing high-surface-area carbon materials such as Ketjen black and graphene. However, these strategies present significant trade-offs: excessive graphite reduces active material loading and energy density, while nanocarbons promote undesirable side reactions that compromise cycling stability. In this study, we introduce cost-effective percolative graphite (PG) with moderate surface area as an effective conductive additive that balances conductivity and surface reactivity. The resulting electrodes, composed of commercial γ-MnO₂ and PG, deliver practical energy densities and superior cycling stability in conventional alkaline electrolytes at the pouch-cell level. These findings underscore the importance of rational conductive network engineering and present guidance in developing high-performance rechargeable Zn-MnO₂ batteries for practical applications.