Pore-structure regulation of biomass-derived carbon materials for an enhanced supercapacitor performance

Abstract

Herein, we report a dual-porogen synthesis strategy to fabricate a micro-/meso-/macroporous carbon material for supercapacitors from biomass. The hierarchically porous carbon material was produced in a facile way by pyrolyzing C₁₀H₁₄N₂Na₂O₈/KOH (dual-porogen) and walnut peel (biomass carbon source) along with HCl solution etching. Such an admirable dual-porogen strategy opened up the closed pores and broadened the range of pore distribution for the carbon material from 0.55–1.76 nm to 0.59–2.53 nm as the mass ratio of walnut peel and C₁₀H₁₄N₂Na₂O₈ increased from 1 : 0 to 1 : 2, making up for the shortcomings of the narrow microporous distribution caused by the use of potassium hydroxide exclusively. As expected, the hierarchically porous carbon materials with a regulated structure with an appropriate pore volume, broadened pore-size distribution, ultrahigh specific surface area, as well as the effective hetratom dopping manifested its remarkable capacitor performances. The highest specific capacitance for a porous carbon material achieved was 557.9 F g⁻¹ (at 1 A g⁻¹) and 291.0 F g⁻¹ (at 30 A g⁻¹). The highest power density could reach up to 5679.62 W kg⁻¹, and energy density achieved was 12.44 W h kg⁻¹, thus greatly promoting its use in the design and synthesis of high-performance electrode materials for supercapacitors.