▎ 摘　　要

Electrochemical exfoliation has been identified as a promising top-down method for obtaining high-quality graphene from graphite. However, conventional anodic exfoliation introduces undesirable oxidation and de-fects in resultant graphene while cathodic exfoliation eliminates that issue but is time and energy intensive. Herein we report a versatile and rapid fabrication approach for gentle (<1 h ultrasonication) cathodic exfoliation of graphite using only 0.05 M K2SO4 in a polyvinyl alcohol (PVA)-based aqueous gel medium as electrolyte. The few-layer graphene obtained via this route demonstrates high quality (ID/IG ratio of 0.07) and minimal oxidation (3.02 at% oxygen). This gel-exfoliated graphene is found to be particularly suitable for micro-supercapacitors (MSCs) achieving a stable working voltage of 1.2 V in aqueous gel electrolyte, good rate capability, high capacitance of 13.7 F cm-3 at 10 mV s-1 and energy density of 2.74 mW h cm-3. Importantly, gel-exfoliated graphene is also compatible with ionogel electrolyte, achieving a high voltage of 3.4 V and resulting in competitive energy density of 14.5 mW h cm-3, outperforming most reported graphene-based MSCs. The MSCs show excellent long cycling performance retaining nearly 100% capacitance over 10,000 cycles. We also demonstrate the mechanical flexibility and integration of the MSCs connected in series and parallel for powering future microscale flexible electronics.