锌离子传导聚合物缓冲层:抑制锌离子水电池锌负极寄生反应  

Zinc-ion conductive buffer polymer layer eliminating parasitic reactions of Zn anode in aqueous zinc-ion batteries

作　　者：陈丹灵 王辉波 任丽 朱梦宇 白正帅 李春新 施灿盛 王汇才 汤育欣 张焱焱 Danling Chen;Huibo Wang;Li Ren;Mengyu Zhu;Zhengshuai Bai;Chunxin Li;Cansheng Shi;Huicai Wang;Yuxin Tang;Yanyan Zhang(College of Chemical Engineering,Fuzhou University,Fuzhou 350116,China;Qingyuan Innovation Laboratory,Quanzhou 362801,China)

机构地区：[1]College of Chemical Engineering,Fuzhou University,Fuzhou 350116,China [2]Qingyuan Innovation Laboratory,Quanzhou 362801,China

出　　处：《Science China Materials》2023年第12期4605-4614,共10页中国科学（材料科学）（英文版）

基　　金：supported by the Platform Supporting Fund of Qingyuan Innovation Laboratory(00623001);the Key Program of Qingyuan Innovation Laboratory(00223002).

摘　　要：由于锌金属在电解液中热力学不稳定而自发地发生寄生反应(析氢、枝晶生长等),水系锌离子电池的商业化应用受到了阻碍.因此,我们构建了一种高粘附性的锌离子传导聚合物聚乙烯醇缩甲醛(PVF)缓冲层,来抑制这些寄生反应的发生,从而提高锌沉积的可逆性.这种致密的人工缓冲层不仅能有效隔绝电解质与锌负极之间的直接接触,还能适应锌沉积/剥离过程中的体积膨胀,并引导锌成核过程.具体来说,PVF层可提高成核过电位,并促进Zn2+的三维扩散过程,使PVF层下的Zn2+沉积通量均匀化.我们设计的PVF@Zn具有高循环稳定性和不易生成枝晶的特点,基于该电极的对称电池的长循环寿命超过5200 h,比Zn负极电池提高了近35倍,甚至可以在40.0 mA cm^(−2)的超高电流密度下稳定运行.此外,PVF@Zn||NVO全电池在1.0 A g^(−1)的条件下进行2400个循环后,仍能保持172.4 mA h g^(−1)的比容量.这种通过消除自发寄生反应并调节锌均匀沉积及成核的策略,为设计实用化高性能锌负极提供了重要借鉴.The spontaneous parasitic reactions(hydrogen evolution,dendrite growth,etc.)of Zn metal hinder the commercial application of aqueous zinc ion batteries.Herein,a highly adhesive zinc-ion conductive buffer polymer layer is constructed using polyvinyl formal(PVF)to prevent these parasitic reactions to enhance the reversibility of Zn deposition.This dense artificial buffer layer can not only effectively isolate the direct contact between the anode and the electrolyte,but also accommodate volume expansion during Zn plating/stripping and guide the process of Zn nucleation.Specifically,this PVF layer increases the nucleation overpotential and promotes Zn2+three-dimensional diffusion process to homogenize the Zn^(2+)flux underneath the layer.Hence,the PVF@Zn exhibits no dendrites and high cycling stability with a lifespan of 5200 h,which is a 35-fold enhancement compared with Zn,and can even run at an ultrahigh current density of 40.0 mA cm^(−2).Moreover,the PVF@Zn||Na2V6O16 full cell maintains a specific capacity of 172.4 mA h g^(−1)(2400 cycles at 1.0 A g^(−1)).This proposed strategy provides a practical insight into designing an excellent-performance Zn anode by eliminating the parasitic reactions and modulating the nucleation of Zn deposition.

关 键 词：buffer polymer layer polyvinyl formal spontaneous parasitic reactions Zn dendrite hydrogen evolution nucleation overpotential 

分 类 号：TM912[电气工程—电力电子与电力传动] O631[理学—高分子化学]