Tuning ionic channels in carbon-binder domains of carbon-based electrodes via nonsolvent induced phase separation (NIPS) method

The design of ionic channels can effectively alleviate ion diffusion limitations in electrodes for supercapacitors, thereby enhancing the performance of energy storage devices. However, few methods have been reported that can tailor ionic channels of electrodes with binders. Herein, we report a nonsolvent-induced phase separation (NIPS) strategy to regulate ionic channels within carbon-binder domains (CBD) of carbon-based electrodes. By systematically analyzing the thermodynamics of different NIPS systems, we established several design principles for tailoring ionic channel structures in CBD. Electrodes with pore sizes ranging from 304 to 740 nm in the CBD and porosities from 0.45 to 1.46 cm³ g⁻¹ are obtained. The capacitive performance of these electrodes in different electrolytes is strongly dependent on the characteristics of the resulting ionic channel structures in CBD. In aqueous electrolytes, high specific surface area (SSA) and well-developed ionic channels in CBD are critical for enhancing electrode capacitive performance. However, in ionic liquid electrolytes, porosity rather than SSA governs the capacitive performance. This work offers a simple and versatile approach for regulating ionic channels in electrode systems with binders.