Rationally tuning ratio of micro- to meso-pores of biomass-derived ultrathin carbon sheets toward supercapacitors with high energy and high power density

• DOI: 10.1016/j.jcis.2021.08.042
• Publication Date: 2021-08-14T22:58:33Z
• Authors: Yuhe Zhang; Chao Wu; Shuai Dai; Lifei Liu; Heng Zhang; Wei Shen; Wei Sun; Chang Ming Li
• Keywords: Power density; Specific surface area; Carbon fibers; Specific energy

The carbon pore structure could have a significant effect on supercapacitor performance; however, this effect has not yet been systematically studied. A facile approach for synthesizing porous, ultrathin carbon sheets while rationally tuning the ratio of micro-to meso-pores via partial corrosion has been developed for the fabrication of high-performance devices. The prepared carbon from biomass with an optimal ratio of micro- to meso-pores has a large specific surface area of 1785 m2 g -1, a high specific capacitance of 447F g -1 at 0.5 A g-1, a high energy density of 15.5-9.7 Wh kg-1, and an excellent power density of 0.062-6.24 kW kg-1. After 10,000 charge-discharge cycles, the capacitance retention was maintained at 95%, which exceeded most of the biomass-carbon-based capacitors. Volcano relationships were found to exist through plots of both specific surface area and specific capacitance versus the micro-to meso-pore ratio. An enhancement mechanism with a rational pore structure is proposed, which not only networks micropores to remove died-end micropores to achieve the largest specific active surface area and high specific capacitance but also realizes fast mass-transport channels, resulting in high power density. This work provides an effective approach based on waste re-use by tuning a rational pore structure for achieving high energy/power density toward green energy applications with universal significance.