Hot–water–induced hollow mesoporous SiOx@RF@CNTs composite with dual–carbon modification for lithium–ion battery anodes

SiO x is a promising anode for lithium–ion batteries, but practical use is hindered by low conductivity, large volume changes, and unstable interfaces. Here, a mild strategy is reported to fabricate a SiO x @RF@CNTs composite anode with a hollow mesoporous architecture and dual–carbon modification. Mesoporous SiO 2 nanospheres are converted into hollow structures by hot–water treatment, which selectively etches the relatively loose interior through mesoporous channels and enables tuning of particle size and shell thickness without harsh acidic or alkaline etchants. The hollow SiO 2 is then coated with resorcinol–formaldehyde resin and combined with carbon nanotubes to build a conductive network. After thermal treatment in an inert atmosphere, SiO 2 is partially reduced to nonstoichiometric SiO x . XPS depth profiling reveals depth–dependent chemical–state variation during this conversion. Owing to synergistic structural buffering, improved interfacial stability, and enhanced charge transport, the electrode delivers 464.8 mAh g −1 after 500 cycles at 1 A g −1 , with good rate capability and favorable kinetics.