Effect of activating agents on the structure and capacitance performance of tofu derived porous carbon

It is very important to identify structural and electrochemical characteristics of universal activators-induced AC for adsorption, catalysis and renewable energy storage. Herein, different activating agents (KOH, NaOH, K₂CO₃, KNO₃) were employed to tailor the microstructures of the tofu-derived ACs. The ACs with plentiful porous structures was synthesized via an ice template and acid treatment enlarging pore strategy, impregnation and carbonization, and the effect of activating agents on morphologies, pore structures and their electrochemical capacitance performance were investigated in detail. There are significant capacitance performance differences in these samples activated by different activating agents at low and high current densities. The rate performance of the ACs (activated by different activating agents) was in the following order: C–NaOH > C–KOH > C–KNO₃ > C–K₂CO₃. The C–NaOH (activated by NaOH) delivered a specific capacitance of 194 F g⁻¹ (0.5 A g⁻¹) and even up to 127 F g⁻¹ at a high current density of 20 A g⁻¹, showing an excellent rate retention (65.5%). To identify the origin of the capacitance enhancement, we resorted to X-ray diffraction (XRD), Raman spectrum, TEM and nitrogen adsorption–desorption techniques and various electrochemical techniques to analyze different activating agents-induced ACs.