Extreme fast-charging silicon anodes enabled by SiOx/C-shell encapsulation in reduced graphene oxide

초록

Limited fast-charging capability and interfacial instability of silicon (Si) anodes remain significant challenges in lithium-ion batteries (LIBs). To address these issues, we demonstrate Si nanoparticles (NPs) encapsulated with SiOx/C shells and chemically anchored via Si-O-C bonds onto reduced graphene oxide (G) nanoplatelets, synthesized through a hydrothermal self-assembly reaction. This unique nano-Si architecture enables rapid electron (e-) transport and enhanced chemical bonding between Si NPs and G during repeated cycling. In addition, the G nanoplatelets serve as a flexible and robust mechanical scaffold within the Si@SiOx/G composite anodes, effectively accommodating the large volumetric changes of Si and maintaining continuous e- transport pathways throughout the electrode microstructure. These combined improvement mechanisms work synergistically to deliver enhanced cycle life and superior 10C fast-charging (-18.8 A g- 1 applied current) and 10C fastdischarging capability for Si@SiOx/G compared with bare Si NP anodes. Electrochemical impedance spectroscopy (EIS) reveals that Si@SiOx/G significantly suppresses contact-impedance growth during repeated cycling compared with bare Si NP anodes. These results highlight the potential of the Si@SiOx/G nanocomposite as a promising candidate for next-generation, high-performance LIBs.

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