Surfactant-assisted self-assembly of flower-like ultrathin vanadium disulfide nanosheets for enhanced hybrid capacitive deionization.

Increasing the salt adsorption capacity (SAC) and durability of electrode materials for hybrid capacitive deionization (HCDI) remain grand challenges. Herein, highly electro-adsorptive and durable vanadium disulfide (VS2) electrode material obtained by a surfactant-assisted hydrothermal method is reported. The distinct three-dimensional flower-like architecture and ultrathin thickness of VS2 nanosheets play a vital role in boosting HCDI performance by exposing a large number of accessible adsorption sites and facilitating the mass transfer of sodium ions. When used in the HCDI system, the flower-like VS2 electrode delivers a high salt adsorption capacity of 72 mg g-1 in 500 mg L-1 NaCl solution at 1.6 V, outperforming the bulk VS2 counterpart with a relatively increased thickness of nanosheets. Moreover, after 10 h of cycling test, the SAC of the flower-like VS2-based HCDI system remains at 93 % of the initial value, showing excellent operation stability. This surfactant-assisted morphology engineering of VS2 nanosheets with ultrathin thickness and unique three-dimensional architecture provides new insight into designing layered electrode materials for efficient HCDI.