三维多孔铜和锌镀层协同构筑无枝晶锂金属电极  

Construction of Dendrite-free Lithium Metal Electrode Using Three-Dimensional Porous Copper and Zinc Coatings

作　　者：樊小勇[1] 张帅 朱永强 敬茂森 王凯鑫 张露露 李巨龙 许磊[1] 苟蕾[1] 李东林[1] Fan Xiaoyong;Zhang Shuai;Zhu Yongqiang;Jing Maosen;Wang Kaixin;Zhang Lulu;Li Julong;Xu Lei;Gou Lei;Li Donglin(School of Materials Science and Engineering,Chang’an University,Xi’an 710061)

机构地区：[1]长安大学材料科学与工程学院,西安710061

出　　处：《化学学报》2022年第4期517-525,共9页Acta Chimica Sinica

基　　金：国家自然科学基金面上(No.22179011);陕西省国际科技合作计划项目(No.2020KW-024);长安大学研究生科研创新实践项目(No.300103714015)资助。

摘　　要：金属锂具有高理论比容量和低氧化还原电位,被认为是高能量密度二次电池最理想的负极材料之一,但其在循环过程中的枝晶生长和体积变化易造成电池失效和安全隐患.以孔径为 5 μm 左右的自制三维多孔铜为基底,在其表面电沉积锌层(3D Cu@Zn),作为金属锂沉积的集流体,构筑无枝晶锂金属电极.三维多孔铜的孔结构稳定,孔径大小适宜,可有效降低局部电流密度和缓解体积变化.锌镀层可降低锂金属的形核过电位,诱导锂的均匀沉积,有效抑制锂枝晶生长.以 3D Cu@Zn 为集流体,锂沉积面积容量为 4 m Ah·cm^(-2),电极表面仍无枝晶出现,经过锂剥离后表面仍然光滑;而铜箔上沉积的锂显示明显的枝晶和不均匀性,3D Cu 上沉积的锂显示局部不均匀性和一定量枝晶.在电流密度为 0.5 和 1m A·cm^(-2),面积容量为 1 m Ah·cm^(-2)条件下,Li||3D Cu@Zn 半电池获得了稳定的库伦效率;在 2 m A·cm^(-2)的高电流密度和 1 m Ah·cm^(-2)的面积容量条件下,Li||3D Cu@Zn@Li 对称电池可稳定循环 700 h 以上;以 3D Cu@Zn@Li 为负极,Li Fe PO_(4)为正极的全电池,在 1 C 倍率下,经过 150 次循环后仍保持 88 m Ah·g^(-1)的容量,均明显优于 Cu 片和 3D Cu 作为集流体的锂金属电极.Metal Li has been considered as one promising anode due to its high theoretical capacity and the lowest redox potential,however its dendrites growth and volumetric changes during cycling easily cause battery failure and safety hazards.Here a three dimensional (3D) porous Cu with pore size of about 5 μm coated with Zn layer is used as current collector for Li deposition to construct dendrite-free metal Li electrode.The suitable pore size and high stability of 3D Cu is beneficial to decrease local current density and buffer volumetric changes,and the Zn layer can decrease the nucleation overpotential of Li,synergistically induce uniform deposition of Li and effectively suppress the growth of Li dendrites.There is no dendrite appears when the 3D Cu@Zn is used as the current collector even the depositing capacity increases to 4 m Ah·cm^(-2),and displays smooth surface after Li stripping,however,the Li on Cu appears obvious dendrites and non-uniformity,Li on 3D Cu appears local non-uniformity and some dendrites.The semi-cell Li||3D Cu@Zn demonstrates stable coulombic efficiency at 0.5 and 1 m A·cm^(-2) with a capacity of 1 m Ah·cm^(-2),the symmetrical cell Li||3D Cu@Zn@Li stably cycle for above 700 h at high current density of 2 m A·cm^(-2) with a capacity of 1 m Ah·cm^(-2).The full cell with 3D Cu@Zn@Li as anode and Li Fe PO_(4)as cathode remains 88 m Ah·g^(-1) after 150 cycles,which is much better than those using Cu@Li plate and 3D Cu@Li as the anodes.

关 键 词：锂金属 三维多孔铜 锌 电沉积 锂枝晶 

分 类 号：TM912[电气工程—电力电子与电力传动] TG146.26[一般工业技术—材料科学与工程]