3D ε-MnO2/electrospun carbon fiber cathodes for aqueous zinc-ion batteries

Abstract

The development of high-performance cathode materials is crucial for advancing aqueous zinc-ion batteries (ZIBs), yet challenges such as poor conductivity and structural instability hinder the practical application of MnO₂-based electrodes. Herein, a three-dimensional (3D) ε-MnO₂/electrospun carbon fiber (ε-MnO₂/CPAN) composite is fabricated via electrospinning and hydrothermal synthesis to address these limitations. The interconnected carbon fiber network derived from PAN not only enhances electrical conductivity but also suppresses the aggregation of ε-MnO₂ nanoflowers, thereby improving interfacial kinetics and structural robustness. As a cathode for ZIBs, the 3D ε-MnO₂/CPAN composite delivers a high specific capacity of 288.6 mA h g⁻¹ at 0.2 A g⁻¹, outperforming pristine ε-MnO₂ (244.3 mA h g⁻¹). Remarkably, it exhibits exceptional rate capability (183.5 mA h g⁻¹ at 3.0 A g⁻¹, 63.6% retention) and cycling stability (90.0% capacity retention after 1000 cycles), attributed to the synergistic effects of the 3D conductive framework and optimized ion/electron transport. Furthermore, the composite achieves a high energy density of 398.3 W h kg⁻¹ at 276.0 W kg⁻¹, surpassing most reported MnO₂-based cathodes. This work provides a scalable strategy for designing MnO₂-carbon hybrids with enhanced electrochemical properties, paving the way for sustainable and high-performance energy storage systems.