Flexible and
self-healable supercapacitors (SCs) show great potential in developing
smart energy storage devices for health care electronics, which call
for the development of nontoxic, biocompatible, and biodegradable
electronics based on natural materials. Most self-healable mechanisms
need external stimuli and a long healing time, which limits their
practical applications. Herein, we developed a mussel-inspired biocompatible
SCs with autonomously self-healing capability through a hybrid system
of gelatin methacrylate (GelMA), cellulose nanocrystal (CNC), and
tannic acid (TA). Mussel-inspired TA on GelMA-CNC hydrogels were optimized
by concentrations and timings to evaluate stress, Young’s modulus,
toughness, and compressive tests for further developing electrochemical
performance on the hydrogel electrode with polyaniline (PANI) and
reduced graphene oxide (RGO). This SC shows an impedance of 5.67 and
6.38 Ω after one healing processing. The specific capacitance,
energy density, and power density of the SCs reached 1861.21 mF cm–3, 20.65 mW cm–3, and 595.59 mWh
cm–3, and retained 96%, 100%, and 82%, respectively,
of their original values after one cut-healing process. This study
demonstrates remarkable potential in advanced smart and biocompatible
energy storage devices.