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 delta-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 delta-MnO2, and H+/Zn2+ co-intercalation mechanism contributes to the enhanced charge storage in the layered K+-intercalated delta-MnO2. This work provides a plausible way to construct a flexible carbon membrane-based cathode for high-performance AZIBs.