锂离子电池用聚多巴胺衍生碳包覆硅纳米颗粒复合材料的制备与性能  

Preparation and properties of polydopamine-derived carbon-coated silicon nanoparticle composites for lithium- ion batteries

作　　者：苏永进 耿茂宁 韩东梅 SU Yongjin;GENG Maoning;HAN Dongmei(School of Chemical Engineering and Technology,Sun Yat-sen University,Zhuhai 519082,China)

机构地区：[1]中山大学化学工程与技术学院,广东珠海519082

出　　处：《电镀与涂饰》2023年第21期47-53,共7页Electroplating & Finishing

摘　　要：实现新型高理论比容量负极材料的应用是开发新一代高能量密度锂离子电池的关键。硅具有4 200 mA·h/g的高理论比容量,远高于商业化石墨负极的比容量,因此在高能量密度锂离子电池的开发中有很好的应用前景。然而硅导电性差,在充放电过程中会发生巨大的体积膨胀而使电极粉化,造成电池性能急剧下降。基于此,本文以聚多巴胺(PDA)作为碳源,采用自模板法成功制备了具有中空结构的硅/碳复合材料(Si@void@C-PDA),主要步骤如下:先利用多巴胺(DA)与Si亲和力较高的特性,在纳米Si颗粒表面原位聚合形成PDA包覆层(对应样品记为Si@PDA),然后通过碳化来实现对硅材料的碳包覆改性(对应样品记为Si@C-PDA),最后采用Na OH溶液对Si@C-PDA进行蚀刻,得到具有中空结构的Si@void@C-PDA。通过X射线衍射仪(XRD)、扫描电镜(SEM)和透射电镜(TEM)分析了上述材料的结构,结果显示经过Na OH蚀刻后成功制备了具有中空结构的硅/碳复合材料。对材料进行电化学性能研究的结果表明,改性后的硅材料在电池中的界面阻抗明显降低。进一步的倍率性能测试表明,Si@void@C-PDA表现出了更高的可逆容量。在0.5C倍率下充放电循环120次以后,Si@void@C-PDA和Si的可逆容量分别为1 290 mA·h/g和848 mA·h/g。这些结果都表明采取自模板法中空结构的改性策略有助于提高硅基负极材料的电化学性能,对推动硅负极材料在新一代高能量密度锂离子电池的应用提供了设计参考。The application of novel anode materials having high theoretical specific capacity is the key to the development of a new generation of high-energy-density lithium-ion batteries.Silicon has a promising application prospect in the development of high-energy-density lithium-ion batteries due to its high theoretical specific capacity of 4200 mA·h/g,which is much higher than that of commercial graphite anode.As for the poor electrical conductivity of silicon,some problems such as pulverization appearing in the battery during the charging and discharging process due to the huge volume expansion of silicon.In this paper,a hollow-structured silicon/carbon composite was prepared by a relatively simple self-templating method using polydopamine(PDA)as carbon source for improving the conductivity of silicon and alleviating the pulverization problem caused by the volume change.Firstly,a layer of PDA film was formed by in-situ polymerization on the surface of Si nanoparticles based on the high affinity between dopamine(DA)and Si,and the product obtained at this stage was marked as [e-mail],carbonization was conducted to realize the modification of Si by being covered with carbon,and the product obtained at this stage was marked as [e-mail],the silicon/carbon composites with a hollow structure which were marked as Si@void@C-PDA were prepared by etching the Si@C-PDA with NaOH solution.The results of X-ray diffraction(XRD),scanning electron microcopy(SEM),and transmission electron microscopy(TEM)proved the successful preparation of Si@[e-mail] electrochemical property testing results showed that the interfacial impedance of the modified silicon material in a lithium-ion battery was greatly decreased.The reversible capacity was 1290 mA·h/g for Si@void@C-PDA and 848 mA·h/g for Si after 120 charge/discharge cycles at a 0.5C rate,indicating that Si@void@C-PDA featured a higher reversible capacity.The said modification strategy is conductive to improving the electrochemical properties of the silicon-based anod

关 键 词：硅/碳复合材料 聚多巴胺 原位包覆 自模板法 中空结构 锂离子电池 

分 类 号：TM911.3[电气工程—电力电子与电力传动] O657.1[理学—分析化学]