Hierarchically porous carbon materials with controllable proportion of micropore area by dual-activator synthesis for high-performance supercapacitors

It is commonly accepted that different structural parameters of electrode materials (i.e. S-BET, S-micro, V-tot, R-t and I-D/I-G) have different effects on the electrochemical properties (i.e. specific capacitance, power density, energy density, and rate capability) in terms of the influencing magnitude and trend. It's therefore extremely desirable to establish a relatively unified structure-function relationship using a single performance indicator. This work luckily finds a defined/composite performance indicator (S-micro/S-BET), which can uniformly influence the capacitor performances. Such analysis is based on the characterization of the as-assembled symmetric electrochemical double-layer capacitors using a series of samples as electrodes (obtained by a dual-activator strategy with C3N3Na3S3 and KOH as dual activators and egg yolk as precursor). All the electrochemical performances (the specific capacitance, rate capability, energy storage performance, etc.) have the same tendency with S-micro/S-BET changes and the peak for all the performances can be obtained when the S-micro/S-BET value is 53.53% in this research. Herein, S-micro/S-BET is expected to be one composite performance indicator to reflect the structure-function relationship and in turn judge the whole performances of the materials through the relationship of S-micro/S-BET and a single performance, thus greatly simplifying the screening of electrode materials for high-performance supercapacitors.