CAJ | 학술논문

通过自组装方式采用一步法制备了锂离子电池硅碳复合电极材料。使用X射线衍射仪( XRD)、透射电子显微镜( TEM)和扫描电子显微镜( SEM)等对样品结构进行表征。结果表明，聚乙烯吡咯烷酮( PVP)包覆的纳米硅颗粒(Si@PVP)均匀嵌入到具有三维网络纳米孔结构的导电石墨化炭黑(GCB)骨架中，形成核壳复合型( Si@PVP-GCB)纳米颗粒，既提高了该复合电极材料的导电性能，又改善了材料的机械强度。在纳米级GCB颗粒内部存在的中空石墨环结构和包覆在纳米Si颗粒外面的PVP包覆层都有效缓冲了纳米Si颗粒在充放电过程中较大的体积变化，从而使纳米Si颗粒更加稳定。电化学测试结果表明， Si@PVP-GCB 电极材料在电流密度为50 mA/g时，经过100次循环后其可逆容量仍达到545 mA·h/g时，远高于商品化的石墨微球( GMs)电极材料的容量(理论容量为372 mA·h/g)。
통과자조장방식채용일보법제비료리리자전지규탄복합전겁재료。사용X사선연사의( XRD)、투사전자현미경( TEM)화소묘전자현미경( SEM)등대양품결구진행표정。결과표명，취을희필각완동( PVP)포복적납미규과립(Si@PVP)균균감입도구유삼유망락납미공결구적도전석묵화탄흑(GCB)골가중，형성핵각복합형( Si@PVP-GCB)납미과립，기제고료해복합전겁재료적도전성능，우개선료재료적궤계강도。재납미급GCB과립내부존재적중공석묵배결구화포복재납미Si과립외면적PVP포복층도유효완충료납미Si과립재충방전과정중교대적체적변화，종이사납미Si과립경가은정。전화학측시결과표명， Si@PVP-GCB 전겁재료재전류밀도위50 mA/g시，경과100차순배후기가역용량잉체도545 mA·h/g시，원고우상품화적석묵미구( GMs)전겁재료적용량(이론용량위372 mA·h/g)。
Si/C composite electrode material, Si@PVP-GCB [ GCB=graphitized carbon black, PVP=poly ( N-vinyl-2-pyrrolidone] was prepared at room temperature by one step-assembly technique. The samples were characterized by X-ray diffraction( XRD) , transmission electron microscopy( TEM) , scanning electron micros-copy(SEM), thermogravimetric analysis(TG) and Raman spectroscopy. It is found that a well-connected three dimensional(3D) nanoporous GCB network uniformly embedded with core-shell nanoparticles of the sili-con nanoparticles(SiNPs) core and the PVP shell was formed. The GCB 3D network not only contributes to the high electrical conductivity of Si@PVP-GCB, but also strengthens the mechanical properties of the elec-trode material. Apart from that, the special hollow structure of GCB nanoparticles and PVP coating shell can buffer the volume variation of SiNPs much more effectively. The electrochemical results show that the Si@PVP-GCB delivered a reversible capacity of 545 mA·h/g at the current density of 50 mA/g after 100 cy-cles, much higher than that of the commercial graphite microspheres( GMs, 372 mA·h/g) .