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Aqueous zinc‐ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self‐doping from manganese metal–organic frameworks (Mn–MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self‐doped polyaniline cathode has a superior specific capacity (273 mAh g−1 at 0.5 A g−1), a high rate property (154 mAh g−1 at 20 A g−1), and excellent cyclability retention (87% over 4000 cycles at 15 A g−1). This research provides fresh insight into the development of innovative polymers as cathode materials for high‐performance AZIBs. [ABSTRACT FROM AUTHOR]

A hierarchical spheroidal MnO@C heterogeneous interface as a cathode material for AZIBs and synthesized through a MOF, which exhibits the excellent cycling stability. [Display omitted] Aqueous zinc-ion batteries (AZIBs) have shown great potential as energy storage devices owing to their high energy density, low cost, and low toxicity. Typically, high performance AZIBs incorporate manganese-based cathode materials. Despite their advantages, these cathodes are limited by significant capacity fading and poor rate performance due to the dissolution and disproportionation of manganese. Herein, hierarchical spheroidal MnO@C structures were synthesized from Mn-based metal–organic frameworks, which benefit from a protective carbon layer to prevent manganese dissolution. The spheroidal MnO@C structures were incorporated onto a heterogeneous interface to act as a cathode material for AZIBs, which exhibited excellent cycling stability (160 mAh g−1 after 1000 cycles at 3.0 A g−1), good rate capability (165.9 mAh g−1 at 3.0 A g−1), and appreciable specific capacity (412.4 mAh g−1 at 0.1 A g−1) for AZIBs. Moreover, the Zn2+ storage mechanism in MnO@C was comprehensively investigated using ex-situ XRD and XPS studies. These results demonstrate that hierarchical spheroidal MnO@C is a potential cathode material for high-performing AZIBs. [ABSTRACT FROM AUTHOR]

• A three-dimensional mesoporous microsphere structural β-MnO 2 /PPy composite was obtained using a facile hydrothermal method. • The electric PPy nanowires linked each β-MnO 2 nanorods to significantly enhance the energy storage behavior of β-MnO 2. • The total capacity was dominated by the synergistic effect between the diffusion-controlled and capacitive behavior. [Display omitted] Mn-based materials as a cathode have drawn much attention in aqueous zinc-ion batteries (AZIBs) for its advantages of low cost and environmental friendliness. However, the sluggish reaction kinetics and low structural stability still limit the electrochemical application of Mn-based materials. Herein, a β-MnO 2 / polypyrrole (PPy) composite was synthesized using a facile hydrothermal method. It delivered a remarkable specific discharge capacity of 361.8 mAh g−1 at a current density of 0.2 A g−1 and great rate performance compared to pure MnO 2 powder. And morphological and electrochemical characterizations revealed that the enhanced electrochemical performance of β-MnO 2 /PPy composite was mainly attributed to the high conductivity of PPy nanowires and the 3D mesoporous microsphere structure, which was assembled by β-MnO 2 nanorods and PPy nanowires. This article provided a new sight of synthesizing Mn-based materials/conducting polymer composites for high-performance cathode in zinc-ion batteries. [ABSTRACT FROM AUTHOR]