Polymer derived SiOC/Sn nanocomposites from a low-cost single source precursor as anode materials for lithium storage applications

Metal- based materials capable of lithium (Li) alloy formation are key to realization of the next generation of high-energy density anodes for Li-ion batteries, owing to their high storage capacity. Designing a good supporting matrix is essential for homogeneously nesting these metallic nanodomains, to effectively utilize their high capacity while tackling the volume expansion issues. Silicon oxycarbides (SiOC), obtained via a polymer derived approach, have recently gained interest as efficient host matrices. However, the high price and limited availability of the precursors for these ceramics present a challenge for their use at a commercial level. Sn nanoparticles, measuring less than 100 nm in size, are formed in-situ within the amorphous SiOC matrix using an economical single-source precursor. The polymeric precursor was indigenously developed from a novel, low cost vinyl functionalized polysiloxane and tin dioleate as the Sn source. Tin dioleate at different wt%, viz. 33–56 %, was uniformly crosslinked with the Q-T polysiloxane and was pyrolysed at 1000 °C in an argon atmosphere to obtain the SiOC/Sn nanocomposites. The electrochemical characterization of SiOC/Sn ceramic nanocomposite anodes exhibit outstanding specific capacities of 650 and 750 mAh g−1 at 372 and 18.6 mA g−1, respectively after 400 charge/discharge cycles. [Display omitted] •The two-step preparation process involves the preparation of the PEOS precursor by non-hydrolytic condensation chemistry and the grafting of organofunctional alkoxysilanes to the PEOS dendrimer surface.•Synthesis of SiOC/Sn nanocomposites involves mixing, polymerisation and conversion to ceramic nanocomposites by pyrolysis, with different compositions of SiOC precursor and Sn dioleate (Sn(Ole)2).•Characterisation techniques include 1H-29Si cross-polarisation magic angle spinning (CPMAS) NMR, DSC/TGA, FTIR, Raman analysis, XRD, elemental analysis and microscopy.•Analysis reveals metallic tin nanodomains within a glassy SiOC network in SiOC/Sn nanocomposites.•Electrochemical performance assessment shows promising behaviour such as high capacities and stability, suggesting potential for use in energy storage systems.