Aerosol Synthesis of Vanadium Oxide-Carbon Hybrid Nanoparticle Clusters for High-Performance Lithium Extraction via Electrochemical Deionization

An aerosol-based synthetic approach is demonstrated for the development of vanadium oxide-carbon hybrid nanoparticle clusters (VOx-C-NPCs) used for the fabrication of a unique electrochemical deionization (ECDI) cell. Hybrid ECDI cells are constructed with a positive electrode of pseudocapacitive VOx-C-NPCs and a negative electrode of battery-like silver–carbon nanoparticle clusters (Ag-C-NPCs). The reversible extraction of Li+ ions and the storage of Cl– ions are conducted through Faradaic reactions on VOx-C-NPCs and Ag-C-NPCs, respectively. The surface of the VOx-C-NPC electrodes can be successfully protected by an anion-doped polypyrrole (PPy) film, by which the structural stability of VOx-C-NPC, in terms of the salt adsorption capacity (SAC) retention, is enhanced to 92%. Remarkably high SAC values of the hybrid ECDI cells are achievable in comparison to the reported values in the field: up to 27.5 mg/g for the bare VOx-C//Ag-C cell and 49.3 mg/g for the PPy-protected VOx-C//Ag-C cell. This work provides a prototype study for the rapid and continuous production of high-performance VOx-C-NPCs using aerosol-based synthesis supported by complementary material characterization. The mechanistic understanding of the material synthesis and the corresponding ECDI process shows promise for achieving an optimal deionization performance in terms of SAC and stability.