Hierarchical Porous Carbon from the Synergistic “Pore-on-Pore” Strategy for Efficient Capacitive Deionization

Capacitive deionization technology for brackish water treatment has been widely studied but currently still suffers from relatively low efficiency. Therefore, a rational design of promising electrode materials has become an urgent task. In this study, a so-called pore-on-pore strategy was developed by chemical activation of the intrinsic porous renewable precursor to generate a micro–meso hierarchical porous carbon. The synergistic effect of the biocomponent and activation agent is the major mechanism for the high porosity. The synthetic carbon has a very high specific surface area (2147.43 m 2 g –1 ). In addition, the carbon exhibits good performance in terms of electroadsorption, with adsorption capacities of 19.35 and 30.64 mg g –1 in solutions with initial concentrations of 500 and 1500 mg L –1 NaCl under 1.2 V applied voltage, respectively. A capacitance retention of 98.7% and charging efficiency of 98.3% were achieved after 100 uninterrupted charge and discharge cycles, indicating relatively good regeneration performance. This research provides a bright way to develop an excellent performance electrode from renewable resources for environmental applications.