Temperature-mediated in-situ formation of antimony nanoclusters inside carbon nanofibers for chloride-driven capacitive deionization

Slow desalination kinetics and poor durability constrain the practical application of faradic electrode-directed capacitive deionization (FDI) systems. In view of this, we developed a temperature-mediated in-situ synthesis strategy for fabricating Sb nanoclusters inside carbon nanofibers (Sb NCs@CNF) as Cl- capturing electrodes for high -efficiency FDI. The synthetic strategy allows "temperature-controlled evaporation" of Sb species from the nanofibers, which not only makes the formation of ultrasmall Sb NCs possible but also provides CNF shells to enhance the structural stability and electrical conductivity of Sb NCs. Benefiting from the specific interaction between Sb species and Cl- ions, ultrasmall size, high surface atom ratio of Sb NCs, as well as the protective CNFs shell, the as-fabricated Sb NCs@CNF-based Cl--driven FDI achieved fast desalination rate (up to 0.24 mg g-1 s-1, through expanding the contribution of surface-controlled capacitance) and excellent cycling stability (only 12.4 % desalination capacity reduction after 30 cycles). In addition to the unprecedented design of Sb NCs-based Cl- capturing electrode mate-rials, this study also provides a paradigm in the temperature-mediated in-situ synthesis of non-coinage MNCs, which may stimulate more research activities in the design and application of carbon-protected MNCs.