Three-dimensional rattan-derived electrodes with directional channels and large mass loadings for high-performance...

Aqueous zinc-ion batteries (AZIBs) have emerged as prospective candidates for wide-scale energy storage, benefiting from their exceptional reliability and budget-friendliness. To tackle the challenge of limited energy density of AZIBs, it is pivotal to explore cathodes with substantial mass loadings. In this study, rattan is converted into a three-dimensional (3D) current collector with directional channels, high compressive strength, good electrolyte affinity, and superior electrochemical stability through a process involving ultraviolet light irradiation-assisted delignification followed by high-temperature carbonization. Using this current collector and a straightforward slurry pasting method, a 3D MnO₂ cathode featuring substantial loading amount of 10 mg cm^-2 for active material can be constructed. This cathode's rich channel structure allows the carbon nanotube/MnO₂ composite material to establish full contact with the electrolyte, significantly facilitating interfacial charge transfer. The optimized cathode achieves an outstanding areal capacity of 3.65 mAh cm^-2 at 0.1 A/g and sustains 1.52 mAh cm^-2 at 1 A/g. Besides, the capacity retention remains at 60.2 % after 1000 cycles, even under such large mass loading. Notably, the fabrication procedure of the 3D cathode is simple, and the associated costs are relatively low compared to other 3D cathodes for AZIBs. These findings present an effective strategy for developing cost-effective and high-performance electrodes with large areal capacities, advancing energy storage technologies.