煤焦油沥青对SiO界面改性增强锂离子电池循环稳定性  

Coal tar pitch modification of the SiO interface enhances the cycling stability of lithium-ion batteries

作　　者：赵方正 张海永[1] 栗彧君 栾晨晖 张玉坤 李刚 王永刚[1] ZHAO Fangzheng;ZHANG Haiyong;LI Yujun;LUAN Chenhui;ZHANG Yukun;LI Gang;WANG Yonggang(School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《复合材料学报》2025年第1期310-322,共13页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(21506251)。

摘　　要：煤焦油沥青具有高碳含量、可调控性和经济性等优点,在制备碳材料和碳复合材料中具有广泛的应用前景。采用沥青对SiO界面改性是抑制SiO自身膨胀、提升首次库伦效率和循环稳定性的有效策略。为改善沥青与基体材料间的结合性能,本文采用添加黏结剂的方式制备负极材料。首先,通过空气交联低温条件下制备高软化点、高结焦值的改性沥青。以聚乙烯吡咯烷酮(PVP)为黏结剂,浸润结合SiO和改性沥青,制备得到前驱体(SiO@PVP@pitch)。通过原位聚合,将改性沥青转化为中间相沥青,然后高温炭化得到SiO/C复合材料,使碳涂层有一定的机械强度又具备导电性。偏光显微镜结果表明碳涂层良好的流线型结构,纤维更加细腻。高分辨透射电子显微镜(HRTEM)结果表明,SiO表面存在厚度约为90~100 nm的含有石墨晶格的碳包覆层。SiO和改性沥青按照5∶3质量比在400℃和900℃的温度条件下聚合和炭化,复合材料表现出优异的电化学性能,在0.5 A/g电流密度下具有550 mA·h/g的高比容量,可逆比容量660 mA·h/g,200次循环后比容量保持率为83.33%,在1.5 A/g电流密度下的比容量为472.8 mA·h/g。电化学阻抗谱(EIS)结果也证明了碳包覆层可以有效提高复合材料的导电性,从而增强SiO电极的循环稳定性。Coal tar pitch has the advantages of high carbon content,controllability and economy,and broad application prospects in preparing carbon materials and carbon composites.Using pitch to modify the interface of silicon monoxide is an effective strategy to inhibit the expansion of silicon monoxide itself and improve the first coulomb efficiency and cycle stability.To improve the bonding performance between pitch and matrix materials,this study prepared anode materials by adding binders.Firstly,we prepared a modified pitch with a high softening point,high coking value,and good rheology by air crosslinking at low temperatures.The precursor(SiO@PVP@pitch)was prepared,using polyvinylpyrrolidone(PVP)as a binder and infiltrating combined with silicon monoxide and modified pitch.Through in-situ polymerization,the modified pitch is converted into mesophase pitch and then carbonized at high temperature to obtain SiO/C composites,so that the carbon coating has certain mechanical strength and electrical conductivity.The results of the polarizing microscope show that the carbon coating has a good streamlined structure and the fiber is more delicate.High-resolution transmission electron microscopy(HRTEM)results show that there is a carbon coating layer containing graphite lattice with a thickness of about 90-100 nm on the surface of SiO.The synthesized SiO/C-5∶3-4 h composites showed excellent performance.It has a high specific capacity of 550 mA·h/g at 0.5 A/g,a reversible capacity of 660 mA·h/g,and a capacity retention rate of 83.33%after 200 cycles.The capacity is 472.8 mA·h/g at 1.5 A/g.Electrochemical impedance spectroscopy(EIS)results also prove that the carbon coating layer can effectively improve the conductivity of the composite material,thereby enhancing the cycle stability of the SiO electrode.

关 键 词：负极 核壳结构 中间相沥青 碳涂层 锂离子电池 

分 类 号：TB332[一般工业技术—材料科学与工程]