A design strategy to significantly improve the lifetime of sustainable supercapacitors

Abstract The transition toward sustainable electronics demands environmentally benign energy storage systems capable of long-term stability and regeneration. Here, an eco-friendly and self-healing supercapacitor is developed by integrating chitosan-bonded, coconut-shell-derived carbon electrodes with a gelatin–sodium acetate polymer electrolyte. A delayed-assembly approach, involving electrode resting followed by gentle rehydration, improves ion accessibility and interfacial wetting, leading to a ~ 70% reduction in equivalent series resistance (from ~0.83 Ω to ~0.27 Ω) and a ~ 40% increase in gravimetric capacitance (~109 F g⁻¹ at 0.4 A g⁻¹) and a ~ 45% boost in energy density (15 Wh kg⁻¹), while reaching a maximum power density of ~4230 W kg⁻¹. The device retains 95% of its initial capacitance after 550000 cycles and exhibits spontaneous performance recovery through reversible hydrogen-bond reformation. This physical regeneration mechanism provides one of the highest reported endurance levels among eco-friendly supercapacitors. The proposed design strategy offers a scalable and sustainable route towards durable, high-performance energy storage devices for the next generation of sustainable and green electronics.