Abstract

Heteroatom doping of nanocarbon films can efficiently boost the pseudocapacitance of micro-supercapacitors (MSCs), however, wafer-scale fabrication of sulfur-doped graphene films with a tailored thickness and homogeneous doping for MSCs remains a great challenge. Here we demonstrate the bottom-up fabrication of continuous, uniform, ultrathin sulfur-doped graphene (SG) films, derived from the peripherical tri-sulfur-annulated hexa-peri-hexabenzocoronene (SHBC), for ultrahigh-rate MSCs (SG-MSCs) with landmark volumetric capacitance. The SG film was prepared by thermal annealing of the spray-coated SHBC-based film, with assistance of a thin Au protecting layer, at 800 oC for 30 min. SHBC with twelve phenylthio groups decorated at the periphery is critical as precursor for the formation of the continuous and ultrathin SG film, with a uniform thickness of ~10.0 nm. Notably, the as-produced all-solid-state planar SG-MSCs exhibited a highly stable pseudocapacitive behavior with an volumetric capacitance of ~582 F cm-3 at 10 mV s-1, excellent rate capability with a remarkable capacitance of 8.1 F cm-3 even at an ultrahigh rate of 2000 V s-1, ultrafast frequency response with a short time constant of 0.26 ms, and ultrahigh power density of ~1191 W cm-3. It is noteworthy that these values obtained are among the best values for carbon-based MSCs reported to date. Further, the as-produced SG film will offer numerous opportunities as an outstanding carbon-based material for electrochemical energy storage and conversion systems, such as metal-free oxygen reduction catalysts, Li-S batteries, and sensors.