摘要
分别以介孔二氧化硅(SBA-15和MCM-48)和硅藻土为硅源,通过镁热还原制备多孔硅,然后向多孔硅中注入有机碳前躯体,经过高温碳化处理得到多孔Si/C复合负极材料。采用X射线衍射仪、Raman光谱仪、场发射扫描电子显微镜和N2吸附脱附测试仪对合成的材料分别进行了表征,研究了多孔Si/C复合材料的电化学性能。结果表明:镁热还原介孔二氧化硅可以得到多孔硅材料,碳加入到多孔硅材料中可以有效提高材料的电子电导率,可明显改善材料的循环稳定性。同时多孔结构可以有效缓解硅基材料充放电过程中的体积应力,提高材料的循环稳定性。以SBA-15、MCM-48和硅藻土为硅源制备得到的3种多孔Si/C复合材料在200mA/g电流密度下循环30次之后的可逆容量分别为712、664、463mA.h/g。
Porous Si/C composite as anode materials were fabricated through magnesiothermic reduction of mesoporous silica （SBA-15 and MCM-48） and diatomite and subsequent impregnating of carbon precursor into the mesoporous Si followed by carbonization. The structure and morphology of the porous composite were characterized by X-ray diffraction, Raman spectroscopy, field emission scanning electron microscope and nitrogen absorption and desorption. Electrochemical performance of the porous composite electrodes was investigated. The results show that the ordered pore structure is retained after the magnesiothermic reduction of well-ordered mesoporous silica. The carbon in the composite can effectively improve the electrical conductivity and enhance cycling stability of the composite. The porous structure may alleviate the volumetric changes and improve cycling stability of the electrode materials during lithium ion insertion and extraction. The three kinds of porous Si/C composites from SBA-15, MCM-48 and diatomite exhibit reversible capacitits of 712, 664, and 463 mA·h/g at a rate of 200 mA/g after 30 cycles, respectively.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2013年第8期1046-1050,共5页
Journal of The Chinese Ceramic Society
基金
国家973项目(2013CB934001)
国家自然科学基金(51172024)
关键词
锂离子电池
负极
多孔硅
碳
复合材料
lithium ion batteries
anode
porous silicon
carbon
composite
