High-surface-area tofu based activated porous carbon for electrical double-layer capacitors

Activated porous carbon (APC), which is used as the electrode material in electrical double layer capacitors (EDLCs), is constantly being developed to enhance its electrochemical performance with low cost. Nevertheless, APC still encounters important challenges due to the limited amount of raw material resources. Herein, we propose a novel and simple approach to synthesize APC from tofu using a simple synthesis process involving carbonization with KOH activation. To obtain the optimized APC, three types of APCs are prepared using different weight ratios of 1:3, 1:4, and 1:5 (W_Tofu/W_KOH) during the carbonization. The optimized APC electrode shows an outstanding specific capacitance of 207 F g⁻¹ at a current density of 0.1 A g⁻¹, a remarkable high-rate performance, an impressive energy density of 25.7–19.9 W h kg⁻¹, and an excellent cycling stability for up to 2000 cycles. Therefore, this unique approach to obtain APC using tofu yield a material with some useful qualities in terms of an increased number of electroactive sites based on a high surface area, and an improved wettability based on the oxygen-containing functional groups on the surface of the APC. Accordingly, tofu-based APC is a promising alternative to conventional APC.