Nanostructured silicon−graphite composites range among the best options forachieving next-generation high-energy anodes forhighperformance lithium-ion batteries. Growing silicon nanowires ongraphite give access tocomposites with high capacity andstability, asthesilicon distributes homogeneously intheelectrode, and thedirect contact provides enhanced mechanical stability even insilicon-rich (>25 wt%)active materials. However, thecost-effective production ofsuch composites remains achallenge. Here, we introduce low-cost catalysts, tinsulfide andtinoxide, enabling silicon nanowire growth atalower temperature than with widely used gold catalysts, and investigate their impact onthecomposite nanostructure andcomposition. The small difference detected inthecomposition oftheproducts obtained with both catalysts required thedevelopment ofareliable method tomeasure thelow-level oxygen content anddistribution within thecomposite. Itrevealed thatoxygen from theSnO 2 growth seeds isincorporated intothesilicon nanowires, while nosulfur from theSnScatalyst could bedetected. We show thatSnSseeds result inananode material ofsuperior initial Coulombic efficiency of81%, while capacity, stability incycling, andratecapability arelessaffected bythechoice ofthecatalyst. Thecomposite anodes, optimized foracapacity of1000 mAh g−1 at C/5rate, deliver anareal capacity ofupto3.6mAh cm−2 and82% capacity retention over 200cycles. Their ratecapability of780 mAh g−1 at5Csurpasses thatofgold-seeded silicon−graphite composites. Theinsight obtained from thisstudy provides guidance forthereliable low-cost synthesis andquality control ofsilicon-containing active materials forLi-ion battery anodes.