Internally-externally molecules-scissored ramie carbon for high performance electric double layer supercapacitors

Abstract

Ramie carbon from the massively three-harvests-one-year and naturally channel-structured ramie straw is typically emerging as the excellent waste-biomass-utilization target toward high-performance electrochemical energy storage devices. However, the traditional activation strategies less fully optimize the pore distribution for the purpose of optimal energy storage capability. Herein, we reported the hierarchically interconnected three-dimensional ramie porous carbon based on waste ramie straw by internally-externally molecules-scissored activation strategy with pre-embedded KOH and re-added KOH molecules coordinately (in-ex-RPC). Benefiting from the synergistically internal-external activation strategy, this in-ex-RPC displays an excellent specific capacitance of 300 F g–1, which is much better than that of ramie porous carbon singly through pre-embedded KOH activation (in-RPC, 194 F g–1) or directly adding KOH activation (ex-RPC, 213 F g–1). Based on it, the aqueous symmetric supercapacitors display a cyclic capacity of 90.9%-retaining after 20,000 cycles at 5 A g–1. Therefore, this work may provide an effective strategy for energy storage applications of waste ramie straw and for further promoting waste biomass utilization.