A wearable cotton fiber-based supercapacitor electrode material with outstanding stability and photothermal performance utilizing AgNWs, NiCoAl-LDH, and PPy-NWs.

Designing cotton fiber (CF) based flexible electrode materials with both electrochemical energy storage and structural stability is crucial for the utilization of flexible supercapacitors in wearable devices. Nevertheless, the electrochemical properties of such materials are often constrained by suboptimal ion diffusion, a limited electroactive surface area, and inadequate structural integrity. Herein, Silver nanowires (AgNWs), NiCoAl hydrotalcite (NCA-LDH), and polypyrrole nanowires (PPy-NWs) are employed to construct a CF-based electrode material (PNHAS/CF) with high stability through a layer-by-layer self-assembly method. The PNHAS/CF with a high capacitance of 1207.58 mF cm at 5 mA cm due to the faster electronic transmission paths of AgNWs and PPy-NWs, and the high specific capacitance of NCA-LDHs. The NCA-LDH stabilizes the PPy-NWs molecular chain, and the PPy-NWs winding structure can further enhance the PNHAS/CF's structural stability and prevent the AgNWs network from being destroyed, which guarantees the exceptional 87.5 % capacitance retention after 2000 cycles. The constructed symmetrical supercapacitor shows an energy density of 36.28 μWh cm at 0.31 mW cm power density. The PNHAS/CF exhibits superb solar spectral absorptivity (~94.8 %) and outstanding solar heating performance. Surprisingly, the fiber-based flexible electrode material and the assembled supercapacitor are expected to find applications in wearable intelligent electronics.