Facile synthesis of dense porous carbon derived from Linum usitatissimum L. root for high mass loading supercapacitors

Abstract

Achieving carbon electrodes with high gravimetric/volumetric/areal capacitances and rate performance, especially at high mass loadings, is crucial for practical applications in supercapacitors. In this regard, a novel dense porous carbon derived from Linum usitatissimum L. root was prepared through a facile in-situ activation method. The prepared porous carbon displays unique pore structure, i.e. abundant sub-nanopores (0.64–0.91 nm) and large size micropores (1.07–1.48 nm), which endow it with large surface area, good electric conductivity, and high packing density. Besides, the prepared porous carbon exhibits abundant active sites on the surface, which promote efficient surface utilization and ion transport. As a result, the resultant porous carbon presents high gravimetric/volumetric/areal capacitances of 421 F g−1/316 F cm−3/8.0 F cm−2 at 1 A g−1. Importantly, the obtained symmetric supercapacitor achieves the high energy densities of 8.16 Wh kg−1/6.12 Wh L−1/163.19 μWh cm−2, even at the high mass loading (20 mg cm−2). This work provides a novel insight for designing and fabricating advanced electrode materials for energy storage application.