Highly Compressible Nitrogen-Doped Carbon Foam Electrode with Excellent Rate Capability via a Smart Etching and Catalytic Process

Freestanding three-dimensional nitrogen-doped carbon foam with large pores is proposed as a promising electrode configuration for elastic electronics. Although it exhibits excellent mechanical performance, the capacitive performances (especially its rate capability) are still unsatisfactory. By using KMnO₄, we demonstrate a smart etching and catalytic process to form highly graphitized and etched nitrogen-doped carbon foam (ENCF) with an exfoliated carbon-shell architecture. These compositional and structural features endow the ENCF electrodes with excellent electron conductivity as well as more ion-accessible electrochemical active sites. Significantly, all-solid-state symmetric supercapacitor devices based on the ENCF electrodes exhibit enhanced specific capacitance and marked high-rate capability. Furthermore, the integrated device has no significant capacity loss under 60% compressive strain.