珊瑚状分级多孔硅的制备及其在锂离子电池负极中的应用

Coralloid-likehierarchically porous silicon for lithium-ion battery anode material

实现规模化生产是高容量硅负极走向商业化面临的最大挑战。报道了1种简单、成本低、产率高的硅材料制备方法,即对溶胶-凝胶反应形成的SiO2-F127(PEO_(106)PPO_(70)PEO_(106),1种三嵌段共聚物)干凝胶进行空气热解和镁热还原处理。而后,利用偶氮化反应在合成的硅材料表面包覆一碳层。利用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、氮气吸脱附实验和热重方法对所制备的硅-碳复合物的形貌和组分进行了分析。结果表明,该复合物中硅含量为76.3%(质量分数),呈珊瑚状形貌,具有微孔-介孔-大孔多级孔道结构和高的比表面积123m^2/g。电化学性能测试结果显示所制备的Si-C复合负极比容量高达2 785mAh/g。

Industrially scalable fabrication of high-capacity silicon anode was the most critical and challenging aspect for its commercialization.In this report,a low-cost,high-yield and simple route was provided to synthesize silicon through air pyrolysis followed by magnesiothermic reduction of SiO2-F127（EO106PO70EO106,a triblock copolymer）xerogel formed by a sol-gel reaction.Furthermore,a diazotization method is employed to coat the silicon with a carbon layer for use as hybrid anode material.X-ray diffraction（XRD）,field emission scanning electron microscope（FE-SEM）,N2 sorption measurement and thermogravimetric analysis（TGA）were used to study the morphology and composition of the composite.The results indicate that the composite containing76.3wt% Si has a coralloid-like micro-meso-macro hierarchically porous structure with a specific surface area of123m^2/g.Electrochemical tests reveal that the as-prepared Si-C anode demonstrates specific capacity as high as2 785mAh/g,indicating improved electrochemical performance.