Graphene Oxide Hybrid with Sulfur-Nitrogen Polymer for High-Performance Pseudocapacitors

Toward the introduction of fast faradaic pseudocapacitive behavior and the increase of the specific capacitance of carbon-based electrodes, we covalently functionalized graphene oxide with a redox active thiourea-formaldehyde polymer, yielding a multifunctional hybrid system. The multiscale physical and chemical characterization of the novel 3-dimensional hybrid revealed high material porosity with high specific surface area (402 m² g^-1) and homogeneous element distribution. The presence of multiple functional groups comprising sulfur, nitrogen, and oxygen provide additional contribution of Faradaic redox reaction in supercapacity performance, leading to a high effective electrochemical pseudocapacitance. Significantly, our graphene-based 3-dimensional thiourea-formaldehyde hybrid exhibited specific capacitance as high as 400 F g^-1, areal capacitance of 160 mF cm^-2, and an energy density of 11.1 mWh cm^-3 at scan rate of 1 mV s^-1 with great capacitance retention (100%) after 5000 cycles at scan rate of 100 mV s^-1.