A biodegradable and flexible solid-state supercapacitor based on a natural polymer dual network hydrogel electrolyte

Abstract

Achieving both biocompatibility and biodegradability remains a significant challenge in developing implantable supercapacitor devices for medical applications. Herein, we report a biodegradable and flexible all-solid-state supercapacitor with a MoS₂@rGO/Mo composite as the electrode material and a dual-network GelMA@CMC hydrogel as the electrolyte. The resulting device exhibits a high areal capacitance of 69.33 mF cm⁻² at a current density of 0.2 mA cm⁻² and maintains over 90% of its original capacitance after 100 bending cycles at 180°. Furthermore, the supercapacitor achieves a high energy density of 9.63 μW h cm⁻² at a power density of 72.98 μW cm⁻². Two identical devices in series and parallel configurations could modulate the voltage and current output, demonstrating the good expansibility of the system. The MoS₂@rGO/Mo electrodes and GelMA@CMC electrolyte achieve near-complete degradation in simulated body fluid within approximately 4.5 months and 21 days, which offers a viable strategy for next-generation biodegradable and implantable energy storage systems.