Ag-modulated mesoporous δ-MnO2 cathodes mitigate pseudo-capacitance and enhance specific capacity of aqueous zinc ion batteries

The development of high-performance aqueous zinc-ion batteries (AZIBs) is promising for energy storage applications, yet challenges persist due to excessive pseudo-capacitance, structural instability and low conductivity of cathode materials. In this study, an Ag-doped mesoporous δ-MnO 2 nanocomposite (Ag–MnO 2 ) was rationally designed as a high-specific-capacity cathode material for AZIBs. Intercalated Ag + stabilize the layered δ-MnO 2 framework and expand ion diffusion channels, while surface-anchored Ag nanoparticles enhance electrical conductivity, optimize pseudo-capacitance and enhance reaction kinetics of δ-MnO 2 . Electrochemical tests reveal that Ag–MnO 2 delivers an amazing specific capacity of 491.7 mAh g −1 , a high power density of 133.1 W kg −1 and a superb energy density of 660.0 Wh kg −1 at 0.1 A g −1 , significantly outperforming pristine δ-MnO 2 , an approximate power density of 135.6 W kg −1 and a poor energy density of 457.1 Wh kg −1 at 0.1 A g −1 . Furthermore, Ag–MnO 2 exhibits exceptional cycling stability, retaining 95.6 % capacity after 800 cycles at 1.0 A g −1 . Ex-situ X-ray diffraction and X-ray photoelectron spectroscopy analyses elucidate the energy storage mechanism of Ag–MnO 2 in AZIBs. A flexible pouch cell fabricated with Ag–MnO 2 demonstrates stable operation under bending conditions, which holds enormous potential in flexible battery applications, achieving high electrochemical performance of 470.3 mAh g −1 , 112.2 W kg −1 and 610.7 Wh kg −1 at 0.1 A g −1 . This work provides a scalable strategy for designing high-performance AZIBs cathodes and offers insights into material regulation for overcoming energy storage limitations, applicable to broader energy storage systems.