Lignin-Based Electrode Materials with a “Spiderweb–Mucilage” Structure for Dual-Energy Storage

With the rapidly growing demand for flexible energy storage devices in wearable electronics, the development of electrode materials that combine high energy/power density with excellent flexibility has become critical. Inspired by the natural "spiderweb-mucilage" structure, we successfully prepared a lignin-based electrode material via electrospinning, carbonization, and hydrothermal processes. This material achieves efficient dual-mode energy storage by mimicking the synergistic roles of the spider web and mucilage. The material features an rGO-CNFs skeleton with high conductivity (4.02 S·cm⁻¹) and flexibility, serving as a "conductive spider web", while NiCo-LDHs nanosheets are anchored as "mucilage" for rapid Faradaic reactions. The above components are tightly interconnected by stable M-O-C chemical bonds, endowing the composite structure with excellent mechanical robustness. This design yields exceptional performance: a specific capacitance of 1492.6 F·g⁻¹ at 1 A·g⁻¹, vastly surpassing pure CNFs (161.4 F·g⁻¹) and rGO-CNFs (440.6 F·g⁻¹). Such excellent electrochemical performance originates from the synergistic effect of dual-energy storage and the significantly enhanced electrolyte wettability of the electrode, whose contact angle with the electrolyte is reduced from 133.3° to 34.4°. The assembled flexible symmetric supercapacitor achieves an energy density of 82.67 Wh·kg⁻¹ at 800 W·kg⁻¹ and retains 94.5% capacitance after 2000 cycles, demonstrating excellent stability.