Interconnected dual-doped polyaniline with enhanced kinetics for high-rate zinc-ion batteries

초록

Aqueous zinc-ion batteries (AZIBs) have emerged as attractive energy storage systems due to their high safety and environmental benignity. Nevertheless, their practical application is hindered by the scarcity of cathode materials capable of delivering both high stability and efficiency. Among various candidates, conducting polymers such as polyaniline (PANI) stand out owing to their superior electrical conductivity, rich redox chemistry, and reversible doping-dedoping properties. In this study, a dual-doping approach was adopted to improve the electrochemical performance of PANI through the incorporation of H2SO4 and ammonium lauryl sulfate (ALS). The synergistic effect of these dopants enhances the conductivity, structural robustness, and morphology of the synthesized PANI-A-H material. Consequently, the dual-doped PANI exhibits excellent electrochemical behavior in AZIBs. In a full-cell configuration, the PANI-A-H cathode delivers a high specific capacity of 267.6 mA h g-1 at 0.5 A g-1 and maintains 222.8 mA h g-1 at 5 A g-1, indicating strong rate capability. Furthermore, it demonstrates outstanding cycling durability, retaining 92.3% and 91.1% of its capacity after 5000 cycles at 1.0 and 5.0 A g-1, respectively, with nearly 100% coulombic efficiency. Electrochemical impedance spectroscopy (EIS) reveals a low charge-transfer resistance, suggesting accelerated reaction kinetics. Ex situ XPS and elemental mapping analyses further clarify the Zn2+ insertion/extraction mechanism at fully discharged (0.4 V) and charged (1.5 V) states after prolonged cycling. This work presents an effective dual-doping strategy for improving conducting polymer-based cathodes in AZIB systems.

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