Hierarchically mesoporous activated carbon prepared from the dissolution of zinc oxide for high-rate electrical double layer capacitors

[Display omitted] •Electrode material for electrical double-layer capacitors.•Hierarchically mesoporous activated carbon.•High specific surface area and high mesopore volume fraction.•Shorter ionic diffusion pathway.•Improved high-rate performance and excellent cycling stability. Due to its highly specific surface area, and excellent chemical stability activated carbon has received a great attention as an electrode material for electrical double-layer capacitors (EDLCs). However, the serious challenge is related to the low mesopore volume fraction of activated carbon, which leads to a low high-rate performance owing to a long path way for ionic diffusion. In the present study, hierarchically mesoporous activated carbon (Meso-AC) was successfully synthesized via the dissolution of zinc oxide (ZnO) nanoparticles during carbonization with the potassium hydroxide activation. In addition, Meso-AC was uniquely derived from protein-based tofu.