Biocompatible, High-Performance, Wet-Adhesive, Stretchable All-Hydrogel Supercapacitor Implant Based on PANI@rGO/Mxenes Electrode and Hydrogel Electrolyte

Functional bioelectronic implants require energy storage units as power sources. Current energy storage implants face challenges of balancing factors including high-performance, biocompatibility, conformal adhesion, and mechanical compatibility with soft tissues. An all-hydrogel micro-supercapacitor is presented that is lightweight, thin, stretchable, and wet-adhesive with a high areal capacitance (45.62 F g−1) and energy density (333 μWh cm−2, 4.68 Wh kg−1). The all-hydrogel micro-supercapacitor is composed of polyaniline@reduced graphene oxide/Mxenes gel electrodes and a hydrogel electrolyte, with its interfaces robustly crosslinked, contributing to efficient and stable electrochemical performance. The in vitro and in vivo biocompatibility of the all-hydrogel micro-supercapacitor is evaluated by cardiomyocytes and mice models. The latter is systematically conducted by performing histological, immunostaining, and immunofluorescence analysis after adhering the all-hydrogel micro-supercapacitor implants onto hearts of mice for two weeks. These investigations offer promising energy storage modules for bioelectronics and shed light on future bio-integration of electronic systems.