▎ 摘　　要

NOVELTY - A graphene-bridged silicon/carbon composite material is prepared by mixing nano-silica powder and flaky graphite, dry-milling, obtaining nano-silica/flaky graphite mixture, wet-milling nano-silica/flaky graphite mixture, saccharide and polymer with deionized water, spray-drying, heat-treating obtained nano-silica/flaky graphite-saccharide-polymer mixture in an argon atmosphere, obtaining silicon/carbon composite material, dispersing graphene in deionized water, ultrasonically mixing, adding silicon/carbon composite material, ultrasonically mixing, filtering, and drying. USE - Graphene-bridged silicon/carbon composite material is used in cathode of lithium ion battery (claimed). ADVANTAGE - The graphene-bridged silicon/carbon composite material is economically prepared by simple process. DETAILED DESCRIPTION - A graphene-bridged silicon/carbon composite material is prepared by mixing nano-silica powder and flaky graphite in a weight ratio of 1:4-1:10, dry-milling at 100-400 rpm for 1-5 hours in a ball mill, obtaining nano-silica/flaky graphite mixture, wet-milling nano-silica/flaky graphite mixture, saccharide and polymer with deionized water at 100-400 rpm for 1-5 hours, spray-drying in a container with inlet temperature of 200-300 degrees C and outlet temperature of 90-150 degrees C, heat-treating obtained nano-silica/flaky graphite-saccharide-polymer mixture at 400-800 degrees C for 2-10 hours in an argon atmosphere, obtaining silicon/carbon composite material, reducing graphite oxide to graphene with hydrazine hydrate in deionized water at 80-95 degrees C for 1-5 hours, dispersing graphene in deionized water, ultrasonically mixing, adding silicon/carbon composite material, ultrasonically mixing, filtering, and drying. The nano-silica powder has particle size of 30-70 nm. The flaky graphite has particle size of 1-10 microns. The weight ratio of saccharide and nano-silica/flaky graphite mixture is 1:1-1:10. The weight ratio of polymer and nano-silica/flaky graphite mixture is 1:1-1:5. The content of graphite oxide with respect to deionized water is 0.1-0.5 g/L. The weight ratio of hydrazine hydrate and graphite oxide is 0.5-1:1. The weight ratio of silicon/carbon composite material and graphene is 10:1-5:1. The content of graphene with respect to deionized water is 0.5-5 mg/L.