Rational Design of Mesoporous Carbon Electrodes with High Mass Loading for Binder‐Free Supercapacitors

Abstract

Abstract A three‐dimensional mesoporous carbon/nickel foam hybrid material has been prepared using an in situ solution growth approach, and its energy storage as a binder‐free supercapacitor electrode is explored. The nickel foam is chosen as an electrically conducting scaffold and also as a porous substrate for the growth of poly(benzoxazine‐co‐resol). After carbonization, tightly packed carbon layers are uniformly coated on the skeleton of the nickel foam. Such carbons show hierarchical porosity (micro‐, meso‐, macroporosity), a high surface area of 811 m 2 g −1 , and graphitic domains. These features allow easy access, rapid diffusion, and a high loading of ions, producing a material in which ion diffusion is faster than in bulk carbon and which is highly efficient in producing an increased double‐layer capacitance. The obtained electrodes exhibit an excellent capacitive behavior in KOH solutions, that is, low contact resistance, high specific capacitance (192 F g −1 ), and good rate performance. Furthermore, the three‐dimensional porous substrates facilitate a high mass loading of active materials, up to 21 mg cm −2 , and per‐area capacitance of 1.18 F cm −2 . This synthesis strategy is scalable and potentially usable for large‐scale production.