Salami-like Electrospun Si Nanoparticle-ITO Composite Nanofibers with Internal Conductive Pathways for use as Anodes for Li-Ion Batteries

We report novel salami-like core-sheath composites consisting of Si nanoparticle assemblies coated with indium tin oxide (ITO) sheath layers that are synthesized via coelectrospinning. Core-sheath structured Si nanoparticles (NPs) in static ITO allow robust microstructures to accommodate for mechanical stress induced by the repeated cyclical volume changes of Si NPs. Conductive ITO sheaths can provide bulk conduction paths for electrons. Distinct Si NP-based core structures, in which the ITO phase coexists uniformly with electrochemically active Si NPs, are capable of facilitating rapid charge transfer as well. These engineered composites enabled the production of high-performance anodes with an excellent capacity retention of 95.5% (677 and 1523 mAh g^-1, which are based on the total weight of Si-ITO fibers and Si NPs only, respectively), and an outstanding rate capability with a retention of 75.3% from 1 to 12 C. The cycling performance and rate capability of core-sheath-structured Si NP-ITO are characterized in terms of charge-transfer kinetics.