Synergetic modulation of graphene oxide and metal oxide particles for exploring integrated capacitance of milk colloid-derived carbon

Abstract

Biomass-derived carbon has great potential as electrode for supercapacitors or batteries, and the rational design and modulation of the porous structure is the key for advanced electro-chemical property. Herein, graphene oxide (GO) sheets and metal oxide particles templates were introduced for modulating the ultramicropores (less than 1 nm) and supermicropores/mesopores (∼ 2 nm) of porous carbon derived from milk colloid, aiming to exploring the potential of biomass-derived carbon as supercapacitor electrodes. Through the synergetic modulations of GO and metal oxide particles, the proposed supercapacitor materials (G-NP-MPC) exhibit high gravimetric (358.4 F/g)/areal (3.58 F/cm2)/volumetric capacitance (277.5 F/cm3) at mass loadings of 10 mg/cm2 in aqueous electrolyte, which accomplishes remarkable improvement of carbon directly derived from milk colloid (181.1 F/g, 1.81 F/cm2 and 140.3 F/cm3) without pore modulation. Apart from aqueous electrolyte, the symmetric supercapacitor (G-NP-MPC) also exhibits relatively high energy density (43.0 W h/kg at the power density of 300 W/kg) in organic electrolyte with the potential window of 3 V. This work amplifies the function of graphene oxide sheets and metal oxide, which can corporately tune the pore size distribution in a narrow scope for enhancing integrated capacitance of biomass-derived carbon.