铁锗合金负极的限域封装及锂离子存储性能  

Nanoconfined encapsulation of iron-germanium alloy anode and its lithium ion storage performance

作　　者：李方坤 王心怡 许希军 巫艺文 杨焱 刘军 LI Fangkun;WANG Xinyi;XU Xijun;WU Yiwen;YANG Yan;LIU Jun(Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials,School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学材料科学与工程学院,广东省先进储能材料重点实验室,广东广州510641

出　　处：《无机盐工业》2022年第4期88-93,共6页Inorganic Chemicals Industry

基　　金：广东省重点领域研发计划项目(2020B0101030005)。

摘　　要：锂离子电池商用负极石墨由于低的理论比容量(372 mA·h/g)无法满足日益增长的高能量密度需求。锗负极材料凭借更高的理论比容量(约为1600 mA·h/g)被认为是一种很有前途的材料。但锗基负极材料在充放电过程中存在巨大的体积变化,使得其电化学性能差。因此,设计并制备了一种独特的锗基复合材料,该材料的合成首先采用溶剂热法制备有机-无机杂化Ge-Fe-O_(x)/EDA纳米线,接着进行多巴胺包覆,随后通过高温焙烧在内部原位生成Fe Ge/FeGe_(2)合金相和表面形成碳包覆,从而制得了限域封装的Ge/FeGe/FeGe_(2)@C纳米线铁锗合金负极。这种独特的结构有效提升锗负极材料的导电性和抑制体积变化,因此复合材料展现出优异的倍率性能(当电流密度为5 A/g时,放电比容量为450 mA·h/g)和良好的长循环稳定性(在电流密度为1 A/g条件下循环400圈后,放电比容量为547 mA·h/g)。Commercial graphite anodes for lithium-ion batteries can’t meet the increasing demand for high energy density due to their low theoretical specific capacity(372 mA·h/g).The Ge anode material is considered a promising material due to its higher theoretical specific capacity(about 1600 mA·h/g).Unfortunately,the Ge anode material has a huge volume change during the charge and discharge process,exhibiting poor electrochemical performance.Therefore,a unique Ge-based composite anode was rationally designed and prepared.First,the organic-inorganic hybrid Ge-Fe-O_(x)/EDA nanowires were prepared by solvothermal method and then coated with dopamine.Subsequently,FeGe/FeGe_(2) alloy phase was formed in situ and carbon coating was formed on the surface by high-temperature roasting,so as to prepare the encapsulated Ge/FeGe/FeGe_(2)@C nanowire irongermanium alloy anode.The unique structure effectively improved the conductivity of the Ge-based anode material and suppressed the volume change,so it exhibited excellent rate performance(the discharge capacity was 450 mA·h/g at the current density of 5 A/g)and excellent long cycle stability(achieving a high discharge capacity of 547 mA·h/g at 1 A/g after 400 cycles).

关 键 词：锂离子电池 锗基负极 纳米线 包覆 限域封装 

分 类 号：TQ131.11[化学工程—无机化工]