High energy density and extremely stable supercapacitors based on carbon aerogels with 100% capacitance retention up to 65,000 cycles

Abstract

In terms of ideal future energy storage systems, besides the always-pursued energy/power characteristics, long-term stability is crucial for their practical application. Here, we report a facile and sustainable strategy for the scalable fabrication of carbon aerogels with three-dimensional interconnected nanofiber networks and rationally designed hierarchical porous structures, which are based on the carbonization of bacterial cellulose assisted by the soft template of Zn-1,3,5-benzenetricarboxylic acid. As binder-free electrodes, they deliver a fundamentally enhanced specific capacitance of 352 F · g–1 at 1 A · g–1 in a wide potential window (1.2 V, 6 M KOH) in comparison with those of bacterial cellulose–derived carbons (178 F · g–1) and most activated carbons (usually lower than 250 F · g–1). The as-assembled supercapacitors exhibit an ultrahigh capacitance of 297 F · g−1 at 1 A · g−1, remarkable energy density (14.83 Wh · kg−1 at 0.60 kW · kg−1), and extremely high stability, with 100% capacitance retention for up to 65,000 cycles at 6 A · g−1, representing their superior energy storage performance when compared with that of state-of-the-art supercapacitors of commercial activated carbons and biomass-derived analogs.