Design and Fabrication of Hierarchically Porous carbon with a Template-free Method

Fabrication of hierarchically porous carbon materials (HPcs) with high surface area and pore volume has always been pursued. However, the currently effective template methods and acid/base activation strategies suffer from the drawbacks of either high costs or tedious steps. Herein, HPcs with 3D macro-mesopores and short-range meso-micropores were fabricated via an easy and sustainable two-step method from biomass. Macro-mesopores were constructed by slightly accumulation/aggregation of carbon spheres ranging from 60 €...nm to 80 €...nm, providing efficient mass diffusion pathways. Short-range mesopores and micropores with high electrolyte accessibility were developed in these spheres by air activation. The obtained HPcs showed surface area values up to 1306 €...m 2 /g and high mesopore volume proportion (63.9%). They demonstrated excellent capacitance and low equivalent series resistance (ESR) as supercapacitor electrode materials, suggesting the efficient diffusion and adsorption of electrolyte ions in the designed hierarchically porous structure.