水系锌离子电池锌负极保护策略

Zinc Anode Protection Strategy for Aqueous Zinc⁃Ion Batteries

水系锌离子电池采用金属锌作为负极材料,具有绿色环保、安全等优势,有望用于大规模储能。锌金属的储量比锂更加丰富,也更容易开采与提纯。同时,锌具有较低的氧化还原电位(-0.76V vs SHE)和较高的理论比容量(820 mAh·g^(-1))和体积容量密度(5854 mAh·cm^(-3))。由于充放电过程中存在锌枝晶和不可逆副产物(如H2、ZnO、Zn4(OH)6SO4)等问题,造成锌负极的库仑效率较低,严重缩短了电池的循环寿命,限制了其实际应用。本文针对锌负极在实际应用中遇到的困难与瓶颈,从微观层面分析了锌负极沉积/溶解的动力学与热力学机理,并从锌电极表面改性、锌片内部结构优化、电解液改性和新型隔膜等方面,介绍了锌负极保护的各种策略,并通过具体实例,分析了其制备方法和改性机理以及最终对电池性能的改善效果,为实用高效的锌负极保护方法提供了思路。最后,文章讨论了锌负极在商业化过程中面临的机遇和挑战,并对未来的研究前景和热点进行了展望。

Aqueous zinc‑ion batteries have advantages in terms of being environmentally friendly and safe with zinc metal anode,which is considered a promising rechargeable battery for large‑scale storage energy systems.Zinc metal is more abundant than lithium and easier to be mined and purified.Meanwhile,it shows a low redox potential(-0.76V vs SHE),high theoretical specific capacity(820 mAh·g^(-1)),and high theoretical volumetric capacity(5854 mAh·cm^(-3)).However,the problems of zinc dendrites and irreversible by‑products(such as H2,ZnO,Zn4(OH)6SO4)on the surface of Zn metal during the charging and discharging processes lead to the low coulombic efficiency of the zinc anode,which seriously shorten the cycle life of the zinc‑ion battery and limit its practical application.Herein,the difficulties and bottlenecks encountered in the practical application of zinc anode are sorted out,in addition,dynamics and thermodynamic mechanisms are tried to analyze from the microscopic level.Subsequently,various strategies are introduced to improve the performance of zinc anode from the aspects of the surface modification technology of the zinc electrode,the optimization of the zinc internal structure,electrolyte modification,and novel functional separator.The preparation methods,modification mechanism as well as final improvement effect on the battery performance are analyzed,which provide new insights into the practical and efficient zinc anode protection method.Finally,the opportunities and challenges faced by zinc anode in the process of commercialization are discussed,and the future research prospects and hot spots are prospected.