一步法高效制备纳米Si/C复合材料及其在高性能锂离子电池中的应用  

A Highly Efficient One-step Preparation Method of Nano-silicon and Carbon Composite for High-performance Lithium Ion Batteries

作　　者：吴卓彦 李至 赵旭东 王倩 陈顺鹏 常兴华 刘志亮 WU Zhuoyan;LI Zhi;ZHAO Xudong;WANG Qian;CHEN Shunpeng;CHANG Xinghua;LIU Zhiliang(Comprehensive Energy Research Center,Institute of Science and Technology,China Three Gorges Corporation,Beijing 100038,China;Key Laboratory of Superlight Materials and Surface Technology,Ministry of Education,College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,China;Beijing National Laboratory for Molecular Science,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China;Key Laboratory for Mineral Materials&Application of Hunan Province,School of Mineral Processing and Bioengineering,Central South University,Changsha 410083,China)

机构地区：[1]中国长江三峡集团有限公司科学技术研究院,综合能源技术研究中心,北京100038 [2]哈尔滨工程大学材料科学与化学工程学院,超轻材料与表面技术教育部重点实验室,哈尔滨150001 [3]北京大学化学与分子工程学院,北京分子科学国家研究中心,北京100871 [4]中南大学资源加工与生物工程学院,矿物材料及其应用湖南省重点实验室,长沙410083

出　　处：《高等学校化学学报》2021年第8期2500-2508,共9页Chemical Journal of Chinese Universities

基　　金：中国长江三峡集团有限公司自主科研项目(批准号:WWKY-2020-0197);中国博士后科学基金(批准号:2020M681075);中央高校基本科研经费(批准号:3072021CF1009)资助~~。

摘　　要：开发了一种一步高效合成纳米硅/碳复合材料的新方法,该方法通过球磨SiCl_(4)、Mg_(2)Si和商业碳片,使SiCl4自下而上还原,原位形成的纳米硅均匀生长在碳片上,高效制备了纳米硅与碳片均匀复合物(Nano-Si/C).该Nano-Si/C用作锂离子电池负极材料展现出高的可逆储锂容量(2450 mA·h/g)、良好的倍率性能及优异的长循环稳定性,在2 A/g电流密度下,经过600次循环后,容量仍然稳定在1400 mA·h/g.其突出的电化学性能主要归因于小尺寸纳米硅与碳片均匀复合的纳米结构,在循环嵌锂/脱锂过程中仍能保持结构和电化学性质的稳定性.Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles and energy storage industries.However,with the rapid development of our society,it is more and more difficult to meet the increasing demand of people for commercial LIBs because their energy densities are generally lower than 250 W·h/kg.Thus,it is urgent to further develop higher-capacity electrode materials to efficiently increase the energy densities of LIBs.Silicon is a very attractive anode material for LIBs with superhigh theoretical capacity(4200 mA·h/g),suitable working potential and abundant earth reserve.Although the pure Si material suffers from poor cycling performance due to very large volume change during repeated lithiation/delithiation,recent researches have shown that the homogeneous carbon composite for nano-silicon could improve the cycling performance effectively.But the preparation methods of nano-silicon and carbon composite are still very complicated,limiting the large-scale preparation and application.A highly efficient one-step method to synthesize the homogeneous composite between nano-silicon and carbon sheet(nano-Si/C)was developed through mechanically milling SiCl4,Mg2Si and commercial carbon sheets.During the milling process,nano-Si is produced from the bottom-up reduction of SiCl4.The in situ formed nano-Si can directly grow on the carbon sheet,further leading to homogeneous composite between nano-Si and carbon sheet.This method possesses a very high reaction efficiency as reactants convert into nano-Si and MgCl_(2) completely without the gene-ration of any impurities.The scanning electron microscopy(SEM)and transmission electron microscopy(TEM)display that the nano-Si supported on carbon sheet is around 30—80 nm in diameter.As the anode material for LIBs,the nano-Si/C sample shows a very high reversible capacity(2450 mA·h/g at 0.2 A/g),good rate performance(1040 mA·h/g at 4.8 A/g)and excellent long cycling stability(retaining 1400 mA·h/g even after 600 cycles at 2 A/g).The

关 键 词：锂离子电池 负极材料 纳米硅/碳复合物 一步合成法 

分 类 号：O646[理学—物理化学]