Ribbon-like activated carbon with a multi-structure for supercapacitors

Abstract

Ribbon-like activated carbon (RAC) has been successfully developed by a two-step activation process based on alkali activation and an electrochemical activation route. The multi-structure of the RAC features a porous graphitic structure with the coexistence of micropores and graphitic structures, mainly originating from the loose packing of the graphite sheets as a result of the degree of graphitization controlled by the carbonization conditions. RAC provides the tremendous benefits of excellent cycle life, high power (3.2 kW kg⁻¹), and high energy density (43.5 W h kg⁻¹) for electric double-layer capacitors, because of its graphitic architecture comprised of micropores and ring-shaped crystalline structures. In addition to investigating the improved electrochemical performance, we observed an interesting feature of the RAC: the obtained RAC has a high structural stability as shown by ex situ high-resolution transmission electron microscopy (HR-TEM). These extraordinary results are attributed to the unique structure of RAC.