Highly Flexible K-Intercalated MnO₂ /Carbon Membrane for High-Performance Aqueous Zinc-Ion Battery Cathode

The layered MnO₂ is intensively investigated as one of the most promising cathode materials for aqueous zinc-ion batteries (AZIBs), but its commercialization is severely impeded by the challenging issues of the inferior intrinsic electronic conductivity and undesirable structural stability during the charge-discharge cycles. Herein, the lab-prepared flexible carbon membrane with highly electrical conductivity is first used as the matrix to generate ultrathin δ-MnO₂ with an enlarged interlayer spacing induced by the K⁺ -intercalation to potentially alleviate the structural damage caused by H⁺ /Zn²⁺ co-intercalation, resulting in a high reversible capacity of 190 mAh g^-1 at 3 A g^-1 over 1000 cycles. The in situ/ex-situ characterizations and electrochemical analysis confirm that the enlarged interlayer spacing can provide free space for the reversible deintercalation/intercalation of H⁺ /Zn²⁺ in the structure of δ-MnO₂ , and H⁺ /Zn²⁺ co-intercalation mechanism contributes to the enhanced charge storage in the layered K⁺ -intercalated δ-MnO₂ . This work provides a plausible way to construct a flexible carbon membrane-based cathode for high-performance AZIBs.