Ion-doped polypyrrole coupled core-shell hierarchical porous carbon electrode material with high desalination capacity for capacitive deionization

Capacitive deionization (CDI) has been a popular research area in the field of seawater desalination in recent years, and the preparation of electrode materials with excellent pore size distribution, electrochemical perfor-mance, and structural stability is the research goal of CDI. In this paper, a core-shell hierarchical porous carbon (CHPC) with ZIF-8-derived carbon and dopamine-derived carbon as the core and shell layers, respectively, was obtained, which is rich in both micropores and mesopores structures. The electrochemical properties of the composites formed by the coupling of CHPC and PPy are greatly improved. The specific capacitances of CHPC@PPy-Cl and CHPC@PPy-DBS (228.11 and 257.04 F & BULL;g-1) are 1.76 and 1.99 times that of CHPC. In addition, the asymmetric cell CHPC@PPy-Cl||CHPC@PPy-DBS has an ultra-high specific adsorption capacity (SAC) of 58.18 mg & BULL;g- 1, which is 2.39 times that of CHPC||CHPC (24.31 mg & BULL;g- 1) for 500 mg & BULL;L-1 NaCl solution. Also, after 30 cycles, the SAC of the CHPC@PPy-Cl||CHPC@PPy-DBS can maintain 97.13%, indicating its excellent cycling stability.