Materials and structural design for preferable Zn deposition behavior toward stable Zn anodes

Benefiting from the high capacity of Zn metal anodes and intrinsic safety of aqueous electrolytes,rechargeable Zn ion batteries(ZIBs)show promising application in the post‐lithium‐ion period,exhibiting good safety,low cost,and high energy density.However,its commercialization still faces problems with low Coulombic efficiency and unsatisfied cycling performance due to the poor Zn/Zn2+reversibility that occurred on the Zn anode.To improve the stability of the Zn anode,optimizing the Zn deposition behavior is an efficient way,which can enhance the subsequent striping efficiency and limit the dendrite growth.The Zn deposition is a controlled kinetics‐diffusion joint process that is affected by various factors,such as the interaction between Zn2+ions and Zn anodes,ion concentration gradient,and current distribution.In this review,from an electrochemical perspective,we first overview the factors affecting the Zn deposition behavior and summarize the modification principles.Subsequently,strategies proposed for interfacial modification and 3D structural design as well as the corresponding mechanisms are summarized.Finally,the existing challenges,perspectives on further development direction,and outlook for practical applications of ZIBs are proposed.

A self-repairing polymer-inorganic composite coating to enable high-performance Zn anodes for zinc-ion batteries

There are some critical issues hindering the practical applications of aqueous zinc-ion batteries(zIBs),although they possess high safety and low cost as one of promising energy storge devices,such as the Zn dendrite growth and the by-product of Zn_(4)SO_(4)(OH)_(6)-xH_(2)O(ZHS)resulted from some side reactions in a mild electrolyte.Herein,a compact and self-repairing solid electrolyte interface(SEl)film,as labeled the PVDF-Zn(TFSI)_(2)-ZHS coating[The PVDF and Zn(TFSI)_(2)are polyvinylidene fluoride and zinc bis(trifluoromethanesulfonyl)imide,respectively],which turns the in-situ generated ZHS into a beneficial ingredient onto the pre-coated PVDF-based composite coating layer containing Zn(TFSI)_(2),was designed and fabricated by a simple doctor blade method.It is shown that the SEl layer can effectively isolate Zn from the electrolyte and homogenize the Zn^(2+)flux,and thus effectively suppress side reactions and dendrites growth.Benefiting from the hybrid SEl layer,a symmetric cell exhibits a high cycling stability over 750h at 2.0 mA/cm^(2)and 2.0 mAh/cm^(2),and meanwhile,a full-cell,coupled with K^(+) pre-intercalationα-MnO_(2)(KMO)cathode,displays excellent rate performance,stable coulombic efficiency and an acceptable cycle life.This work provides a feasible approach for simple and scalable modification of Zn anodes to achieve high performance.