Conformal Conversion of Polyphosphazene@SbMoO Nanowires to N/S-Doped/Carbon-Coated SbPO/MoO for High-performance Lithium Storage.

Alloy-type antimony (Sb) and conversion-type molybdenum (Mo) anodes have attracted extensive attention in the application of lithium-ion batteries (LIBs) owing to their high theoretical capacity. In this study, SbMoO nanowires are prepared via a hydrothermal method and assessed their thermal behavior upon heat treatment, observing an intriguing transformation from nanowire to SbO/MoO nanosheets. To enhance structure stability, the SbMoO nanowires are successfully coated with a polyphosphazene layer (referred to as PZS@SbMoO), which not only preserved the nanowires form but also yielded N/S co-doped carbon-coated SbPO/MoO (NS-C@SbPO/MoO) nanowires following annealing in an inert environment. This composite benefits from the stable PO anion that serve as a buffer against volume expansion and form a LiPO matrix during cycling, both of which substantially bolster ion transport and cycle endurance. Doping with heteroatoms introduces numerous oxygen vacancies, augmenting the number of electrochemically active sites, and carbon integration considerably enhances the electronic conductivity of the electrode and alleviates the volume-change-induced electrode pulverization. Employed as anode materials in LIBs, the NS-C@SbPO/MoO electrode exhibits remarkable cycling performance (449.8 mA h g at 1000 mA g over 700 cycles) along with superior rate capability (394.2 mA h g at 2000 mA g).