| Graphene nanoscroll(GNS)is a one-dimensional(1D)tubular nanomaterial made by rolling up graphene nanosheet.Compared with other 1D carbon materials,such as carbon fiber and carbon nanotubes,graphene nanoscroll can wrap other materials and provide conductive pathways.Its open ends allow the exchange of species between the internal and external environment.Therefore,graphene nanoscroll have broad application prospects in energy storage,catalysis,and other related fields.In this paper,reduced graphene oxide nanoscroll(RGONS)and their composites are prepared by organic solvent assisted lyophilization(OSAL),and their electrochemical performance in supercapacitors and lithium-ion batteries are investigated.A non-woven fabric composed of RGONS is prepared from graphene oxide dispersion by OSAL and chemical reduction in ethanol environment,and used as flexible electrode materials in supercapacitor.The experimental results show that the nanoscroll structure inhibits excessive aggregation between reduced graphene oxide(RGO)sheets,which is commonly found in other flexible films such as compressed reduced graphene oxide aerogel membranes and filtrated reduced graphene oxide membranes,thereby exhibiting higher rate performance.A solid supercapacitor with RGONS nonwoven fabric as the electrodes exhibits good mechanical flexibility and fatigue resistance during the electrochemical testing process.Starting from the dispersion of graphene oxide and silicon nanoparticles,the nano-silicon@reduced graphene oxide nanoscroll composites are prepared by OSAL method,and applied as anode materials in lithium ion battery.The RGONS encapsulates silicon nanoparticles in its limited interior space,and inhibits the volume expansion of the silicon nanoparticles during the charging and discharging process,thereby effectively improving the cycle sta’bility of the electrodes.RGO also establishes a conductive path between the silicon nanoparticles and the curnent collector,and helps stabilize the formation of the solid electrolyte interface film.The composite nanoscrolls exhibit higher capacity,Coulombic efficiency,and cycle stability compared with the composites that are prepared by simply blending silicon nanoparticles and RGO nanosheets.In this thesis,two kinds of high-performance electrode materials based on RGONS are prepared,and the mechanism of improving the electrochemical energy storage performance by the nanoscroll structure is elucidated.Our results will provide a new route to the design of the next generation of high-performance electrode materials. |
