Biomass Derived Carbon Spherules And The Composites Utilized As Anode In Lithium Ion Batteries

Monodispersed and size-controlled carbon spherules are great potential for many applications because of its unique morphology and properties.As anodes for lithium ion batteries（LIBs）,carbon spherules（CSs）with sizes ranged in nanometers to micrometers in diameter have attracted considerable attention owing to their unique morphology,electrochemical performances.So far,several protocols have been developed successfully for the preparations of CSs,but it is still challenging to prepare high quality CSs in bulk scale through cost effective ways.In this work,carbon spherules were prepared simply through hydrothermal treatment on glucose using different acids as catalysts.The effects of different organic and inorganic acids as catalysts on the formation of carbon spherules were studied systematically.It was found that using organic dicarboxylic acids,the as-generated carbon spherules show usually overall better monodispersity,narrower size distribution,and easier for graphitization.Furthermore,the composites of CSs with chemically reduced graphene oxide（CRGO）（CRGO/CSs）,and CSs with Fe₃O₄（Fe₃O₄/CSs）were also prepared,and their electrochemical properties as anodes for LIBs were explored.The Fe₃O₄/CSs as active materials for anodes of LIBs showed higher specific capacity,but relatively poor cycling stability than the bare CSs.The composites of as-obtained CSs catalyzed by different acids with CRGO prepared by physical blending and annealing treatment showed even better electrochemical performances as anodes LIBs.Comparely the composites of carbon spherules produced with organic dicarboxylic acids as catalysts have unique electrochemical properties.Specifically,the composite prepared with CSs catalyzed by glutaric acid showed the highest reversible specific capacity,2281 mA h g^-1,at charge-discharge current densities of 0.2 A g^-1,which should be practically useful for LIBs.