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The profiled carbon fiber-supported SiOx LIB anodes with abundant capillary channels and high contact area can improve lithium-ion transport and buffer the SiOx volume changes, resulting in the improvement of the cell performance.

With the widespread use of mobile electronic devices and increasing demand for electric energy storage in the transportation and energy sectors, lithium-ion batteries (LIBs) have become a major research and development focus in recent years. The current generation of LIBs use graphite as the anode material, which has a theoretical capacity of 372 mAh•g -1 . Tin-based materials are considered promising anode materials for next-generation LIBs because of their favorable working voltage and unsurpassed theoretical specific capacity. However, overcoming the rapid storage capacity degradation of tin caused by its large volumetric changes (> 200%) during cycling remains a major challenge to the successful implementation of such materials. In this paper, SnO2 nanoparticles with a diameter of 2-3 nm were used as active materials in LIB anodes and a threedimensional (3D) graphene hydrogel (GH) was used as a buffer to decrease the volumetric change. Typically, SnCl4 aqueous solution (18 mL, 6.4 mmol•L -1 ) and graphene oxide (GO) suspension (0.5% (w, mass fraction), 2 mL) were mixed together via sonication. NaOH aqueous solution (11.4 mmol•L -1 , 40 mL) was slowly added and then the mixture was stirred for 2 h to obtain a stable suspension. Vitamin C (VC, 80 mg) was then added as a reductant. The mixture was kept at 80°C for 24 h to reduce and self-assemble. The resulting black block was washed repeatedly with distilled deionized water and freeze-dried to obtain SnO2-GH. In this composite, GH provides large specific surface area for efficient loading (54% (w)) and uniform distribution of nanoparticles. SnO2-GH delivered a capacity of 500 mAh•g -1 at 5000 mA•g -1 and 865 mAh•g -1 at 50 mA•g -1 after rate cycling.