The optimized flow-electrode capacitive deionization (FCDI) performance by ZIF-8 derived nanoporous carbon polyhedron

Flow-electrode capacitive deionization (FCDI) has developed as a promising technology to realize the highly efficient and low-energy-consumed desalination process. To deliver better desalination performance, the flow-electrode with high capacitance and low resistance is essential. As for the traditional AC flow-electrode, although it is low-cost and wide-applied, the relatively low capacitance and poor conductivity are the limitations for its further development. Here, we propose a novel flow-electrode material, nanoporous carbon polyhedron (NCP), which was prepared by ZIF-8 followed by carbonization and activation process and have a higher surface area and larger specific capacitance than AC. The desalination experiments showed that the current density of FCDI system based on NCP is about 2.5 times larger than that of AC, exhibiting a higher desalination rate of 20.98 μg cm−2 min−1 for NCP. Moreover, the desalination energy consumption and efficiency can keep relatively stable after the long-time continuous desalination cycling. This current research may be significant for the future promising application of high-performance FCDI system.