黄铜集流体在无负极锂金属电池中的应用研究

Brass foil as negative current collector for anode-free Li-metal batteries

虽然无负极锂金属电池(AF-LMBs)具有能量密度高、结构简单等优势,但是金属锂在负极集流体界面不可逆的沉积/剥离过程以及与电解液之间的副反应会大量消耗电池中有限的活性锂,导致电池容量迅速衰减。开发高性能的负极集流体是提升AF-LMBs循环寿命的有效策略之一。因此,本文研究了商业黄铜箔(F-Cu-Zn)作为负极集流体在AF-LMBs中的电化学性能,并且结合多种表征技术揭示了F-Cu-Zn电极在循环过程中的结构演变。结果表明:与商业铜箔(F-Cu)相比,F-Cu-Zn含有丰富的亲锂位点,诱导金属锂均匀成核与生长,所组装的Cu-Zn||NCM712软包全电池的室温循环寿命从75次增加至117次。此外,F-Cu-Zn电极中的Zn元素会在循环过程中不断溶解,最终在电极表层形成三维多孔结构。

Although anode-free lithium metal batteries(AF-LMBs)have the advantages of high energy density and simple structure,the irreversible deposition/stripping process of lithium metal at the negative current collector interface and the side reaction with the electrolyte will consume the limited active lithium ions and result in the rapid capacity decay of the battery.Developing high-performance negative current collector is one of the effective strategies for prolonging the durable life of AF-LMBs.Hence,the electrochemical performance of commercial brass foil(F-Cu-Zn)as a negative current collector in AF-LMBs was investigated in this work.Meanwhile,the structural evolution of F-Cu-Zn electrodes during cycling process was also revealed by combining various characterization techniques.The results show that,compared with commercial Cu foils(F-Cu),F-Cu-Zn foils with abundant lithiophilic sites can induce uniform nucleation and growth of lithium metal.Therefore,the cycling life increases from 75 to 117 in the assembled F-Cu-Zn||NCM712 soft pack battery at room temperature.In addition,the Zn element in the F-Cu-Zn electrode will be continuously dissolved into the electrolyte during the cycle,resulting in the formation of a three-dimensional porous structure on the surface of the electrode.