Synthesis and characterization of in situ carbon-coated Li2FeSiO4 cathode materials for lithium ion battery

Li 2 FeSiO 4 /C composites with in situ carbon coating were synthesized via sol–gel method based on acid-catalyzed hydrolysis/condensation of tetraethoxysilane (TEOS) with sucrose and l -ascorbic acid as carbon additives, respectively. As-obtained Li 2 FeSiO 4 /C composites prepared with l -ascorbic acid as a carbon additive are composed of nanoparticulate Li 2 FeSiO 4 in an intimate contact with a continuous thin layer of residual carbon and exhibit large specific surface area up to 395.7 m 2 g −1 . The results indicate that structure of the residual carbon is graphene-rich with obviously lower disordered/graphene (D/G) ratio. These as-obtained Li 2 FeSiO 4 /C composites exhibit first discharge capacity of 135.3 mAh g −1 at C/16 and perform cycling stability, which are superior to those of Li 2 FeSiO 4 /C composites synthesized with sucrose as a carbon additive.