Ag nanowire/lignin-derived carbon aerogels with enhanced interfacial charge transfer for efficient chloride removal in capacitive deionization

Silver-based nanomaterials have demonstrated great potential for chloride removal via capacitive deionization (CDI) due to high conductivity, tunable surface/interface properties, and excellent selectivity. Unlike silver nanoparticles, silver nanowires (Ag NWs) can more easily form 3D conductive networks. In this work, hierarchical porous Ag NWs/lignin-based carbon aerogels (Ag NWs/CAs) were fabricated using a super-fast freezing and ice-segregation-induced self-assembly method. Specifically, we utilize the strong chelating ability and abundant surface functional groups of lignin to effectively anchor and disperse Ag NWs while significantly shortening the sol-gel and aging processes during aerogel preparation. In Ag NWs/CAs, the Ag NWs form a 3D interconnected framework that establishes an efficient conductive network, substantially enhancing charge and ion transport rates. Meanwhile, the lignin-derived carbon contributes excellent conductivity and electrolyte wettability. Benefiting from these unique structural and surface advantages, the optimized Ag NWs/CA, utilized as a CDI electrode, demonstrates superior electrochemical chloride removal performances under 1.2 ​V applied voltage in a solution with initial conductivity of 1 000 ​μS ​cm −1 , achieving a Cl − adsorption capacity of 90.4 ​mg ​g −1 and an average Cl − adsorption rate of 1.5 ​mg ​g −1 min −1 . This study provides new insights into the development high-performance CDI electrodes for chloride removal.