石墨烯基高性能锂电材料结构设计与界面调控功能材料化学与化工专业论文.docxVIP

石墨烯基高性能锂电材料结构设计与界面调控功能化石墨烯用于高性能锂硫电池。开发了一种通过低温水热将乙二胺功能化石墨 石墨烯基高性能锂电材料结构设计与界面调控 功能化石墨烯用于高性能锂硫电池。开发了一种通过低温水热将乙二胺功能化石墨 烯(EFG)表面的方法，通过液相氧化还原反应负载硫，熔融扩散得到硫涂覆的EFG复合 物(EFG．S)，试验表征和理论计算结果表明EFG可实现对硫及放电产物硫化锂的强吸附， 同时石墨烯的物理限制作用及良好的机械性能均有利于EFG．S电极结构稳定。350次循 环后保持650 mAh g-1的高比容量，对应于80％的比容量保持率。 石墨烯基碳／硫／聚吡咯三明治复合正极的构筑。以GO为前躯体通过纳米铸造、硫 熔融扩散和聚吡咯fPPy)涂覆的路线成功将硫封装在聚吡咯和石墨烯基介孔碳片 (Gcs@PPy)之间，三明治式GCS@PPy保持了石墨烯的二维片状结构，有利于提高硫的 利用率和电解液的扩散，同时PPy、石墨烯和介孔碳均可有效提高硫的导电性，并缓冲 硫在充放电过程中的体积变化，从而有利于电极的结构稳定，所得GCS@PPy电极可展 现出高达935 mall g以的首放电比容量，400次循环测试中每圈容量衰减率仅为O．05％， 4 C电流密度下430 mAh g‘1的高倍率性能。 关键词：石墨烯；金属氧化物；硫；锂离子电池；锂硫电池 万方数据 大连理工大学博士学位论文Abstract 大连理工大学博士学位论文 Abstract Due to the advantages of high energy density，high power density and no memory effect， lithium ion baaeries(LIBs)have drawn much attention，and have be applied in portable electronic devices．However，present commercial electrode materials can not deliver sufficient energy to realize longe range and fast charge and discharge cycles for electric vehicles． Therefore．electrode materials witll high performance characteristics are of great significance in terms of scientific reseach and practical applications．In this thesis，electrochemical active materials with high theoretical specific capacity(metal oxide or sulfur)and graphene nanosheets with excellent physical and chemical properties were employed to construct high performance electrode materials，mainly addressing the poor structure stability of metal oxide anodes and shuttle effect of sufur cathodes，and the applied scientific concept is that both nanotructuml design and interfaciaI engineering should be optimized to construct high performance electrodes．SeverM high performance lithium electrodes were developed in this thesis，such as compressible graphene／CoO aerogels as binder—free electrodes，metal oxide hollow nanostructures strongly coupled、Ⅳith graphene nanosheets．graphene／Sn02／polyaniline sandwiched anode and functionlized graphene／sulfur ccmhode，graphene／Sulfur／polypyrrole sandwiched cathode．The