Agar Acts as Cathode Microskin to Extend the Cycling Life of Zn//α-MnO₂ Batteries

The Zn/MnO₂ battery is a promising energy storage system, owing to its high energy density and low cost, but due to the dissolution of the cathode material, its cycle life is limited, which hinders its further development. Therefore, we introduced agar as a microskin for a MnO₂ electrode to improve its cycle life and optimize other electrochemical properties. The results showed that the agar-coating layer improved the wettability of the electrode material, thereby promoting the diffusion rate of Zn²⁺ and reducing the interface impedance of the MnO₂ electrode material. Therefore, the Zn/MnO₂ battery exhibited outstanding rate performance. In addition, the agar-coating layer promoted the reversibility of the MnO₂/Mn²⁺ reaction and acted as a colloidal physical barrier to prevent the dissolution of Mn²⁺, so that the Zn/MnO₂ battery had a high specific capacity and exhibited excellent cycle stability.