用甲壳素纳米片构建高性能硅碳复合负极材料  

High-Performance Si/C Anode Material Constructed with 2D Chitin Nanosheets

作　　者：刘大进 麻景淇 高凌峰 蔡杰[3] 余创 谢佳 Liu Dajin;Ma Jingqi;Gao Lingfeng;Cai Jie;Yu Chuang;Xie Jia(State Key Laboratory of Advanced Electromagnetic Engineering and Technology,School of Electrical and Electronic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Hubei Engineering Center of Natural Polymerbased Medical Materials,College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,China)

机构地区：[1]华中科技大学电气与电子工程学院,强电磁工程与新技术国家重点实验室,湖北武汉430074 [2]华中科技大学材料科学与工程学院,材料成型与模具技术国家重点实验室,湖北武汉430074 [3]武汉大学化学与分子科学学院,湖北省天然高分子基医用材料构建工程技术研究中心,湖北武汉430072

出　　处：《稀有金属》2022年第9期1125-1132,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51821005,U1966214,21334005,21875170)资助。

摘　　要：为克服硅在储锂时的剧烈体积膨胀,目前文献报导了许多用石墨烯或碳纳米管等先进碳材料制备硅碳复合材料的研究。这些碳材料的高成本和低产量使它们难以满足工业大生产的需求。本文以水热反应剥离出的甲壳素纳米片(CNs)、聚乙烯醇(PVA)和纳米硅为原材料,通过简单的混合和干燥过程,得到CNs,PVA和纳米硅组成的块状复合材料CNs-Si-PVA,实现PVA和CNs对纳米硅的包覆。高温热解后,CNs衍生的二维碳材料(2DC)和PVA衍生的无定形碳共同包覆纳米硅形成硅碳复合材料2DC-Si-C。碳包覆能有效缓冲硅负极材料在重复脱锂/嵌锂过程中的体积变化,并提高导电性,使合成的2DC-Si-C用作锂离子电池的负极材料时表现出优异的循环稳定性及倍率性能。在1.0 A·g^(-1)的大电流密度下,经过300圈循环后,2DC-Si-C复合材料仍保留760 mAh·g^(-1)的放电比容量;倍率测试中,在2.0 A·g^(-1)的电流密度下,该复合材料首次放电能发挥出865 mAh·g^(-1)的比容量。绿色环保的碳前驱体、简单的加工方法以及优异的储锂性能,使2DC-Si-C复合材料有望成为下一代高性能锂离子电池(LIBs)的负极材料。Si has been considered as one of the most promising anode materials for the next-generation Li-ion batteries(LIBs)be-cause of its ultrahigh theoretical capacity and low lithiation potential.However,the industrial application of Si anode is hampered by its huge volume change during the lithiation/delithiation process.The huge volume variation leads to the pulverization of Si particles,the over-growth of the solid electrolyte interphase(SEI)layer,loss of electrochemical contact,thus yields fast deterioration of capaci-ty.In addition,the low intrinsic electrical conductivity is also an obstacle for Si anode with excellent electrochemical performances.To improve the cycling stability and rate performance,Si is often combined with advanced carbon materials such as carbon nanotubes(CNT),graphene(G),and so on to construct Si/C composites.However,these advanced carbon materials are limited by their high cost and low output and cannot meet the requirements of industrial applications.In this work,we presented a novel Si/C composite for lithium storage,using polyvinyl alcohol(PVA)and two-dimensional(2D)chitin nanosheets(CNs)as carbon precursors.CNs were exfoliated from commercial chitin powders through a simple and scalable hydrothermal process.Then CNs,PVA and nano Si were mixed in deionized water at 90℃,followed by continuously stirring at this temperature to evaporate the water and obtain the robust in-termediate CNs-Si-PVA.Benefiting from the strong hydrogen bonding effect between CNs,PVA and Si nanoparticles,Si nanoparticles were tightly encapsulated by CNs and PVA.After carbonization at 850℃for 3 h in Ar atmosphere,2DC-Si-C composite was obtained.The phase,structure,morphology and elemental composition of the sample were studied by X-ray diffraction(XRD),thermogravimet-ric(TG)analysis,X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and transmission electron microsco-py(TEM).SEM and TEM results demonstrated that Si nanoparticles were dual-confined by~12 nm amorphous carbon layer derived from

关 键 词：甲壳素 二维(2D)碳纳米片 锂离子电池(LIBs) 负极材料 硅碳复合材料 

分 类 号：O646[理学—物理化学]