基于三维集流体的无枝晶锂金属负极

随着电化学储能市场的迅猛发展, 当前商用锂离子电池难以满足人们对高能量密度储能器件的需求. 锂金属具有高比容量和低氧化还原电位等优点, 被认为是下一代二次电池的理想负极材料. 然而, 锂金属负极在充放电过程中会出现体积变化大、 枝晶生长、 界面不稳定等问题, 严重阻碍了其在二次电池中的实际应用. 三维多孔材料具有骨架/空间互穿网络结构、 比表面积大、 孔隙发达和机械性能好等物理特性, 用作金属锂负极的集流体, 在锂沉积/溶解过程中可以起到降低局部有效电流密度、 均匀电场分布和降低锂离子浓度梯度的作用, 有望实现锂的均匀成核和无枝晶沉积, 同时抑制了电极的体积膨胀. 尽管有关三维集流体的研究报道不断出现, 但综合系统评价现有各种三维集流体体系的工作鲜见报道. 本文聚焦锂金属负极三维集流体的构建及应用研究进展, 首先分析了三维集流体抑制锂枝晶生长的基本原理及局限性, 继而重点关注了三维集流体的结构调控、 表面改性和功能化等应对策略对锂成核、 沉积过程的影响, 并对不同材质三维集流体的优缺点进行了归纳总结. 最后, 面向实用化, 分析并展望了三维集流体应用于锂金属电池的发展前景.

Advanced 3D Current Collectors for Dendrite-free Lithium Metal Anode

Nowadays， with the rapid development of electrochemical energy storage market， the present commercial lithium ion batteries cannot meet the growing demand for energy storage devices with higher energy density. Metallic lithium is strongly regarded as the most promising anode candidate for next-generation high-energy-density batteries， due to its superior theoretical capacity and low electrochemical potential. However， there are still several determent issues to be addressed during charging and discharging， including huge volume change， lithium dendrite growth and unstable interface， which seriously hinder its practical application in secondary batteries. Three-dimensional（3D） porous matrixes are considered as ideal current collectors to realize a uniform Li nucleation and dendrite-free Li plating as well as to overcome volume expansion simultaneously. 3D current collectors possess spacial framework， large surface area， abundant pores and high mechanical properties， which enable a lower local current density， uniform electric field distribution and reduced concentration gradient for lithium anode during Li plating/stripping. Although many research papers related to 3D current collectors have been published recently， few comprehensive and systemic evaluation was revealed on the currently various 3D current collector systems. This review focuses on the research progress referring to structure design and practical application of 3D current collectors in lithium anode. Firstly， an analysis about the principle and limitation of lithium dendrite suppression by 3D current collector is provided. Secondly， we pay close attention to strategies for controllable construction， surface modification and functio-nality of a 3D structure and resulting improvement of Li deposition. A comparison among various 3D hosts based on different materials is summarized， in terms of advantages and shortages. Finally， perspectives of the future research based on the practical application in this field are discussed.