Construction Of Interfacial Regulated Zinc Anode And Its Application In Fabric-based Zinc-ion Batteries

Smart wearable technology is a multi-disciplinary disruptive technology,which has gradually been widely used in military,education,entertainment,health care and other fields in recent years.With the rapid development of smart wearable devices towards light,thin,convenient and highly integrated,it is urgent to develop matching high-security flexible portable energy storage devices.Aqueous zinc-ion batteries have become the most potential battery system for energy supply applications in wearable devices due to their advantages such as low cost,high capacity,and ecological safety.However,zinc anode is confronting the problems such as zinc dendrites,corrosion,hydrogen evolution and passivation in practical applications,resulting in performance defects of the battery in terms of capacity,rate,coulombic efficiency and cycle life,which greatly limit the application of aqueous zinc-ion batteries.In order to solve the above problems,researchers have invested a lot of research and proposed a series of strategies to improve the zinc anode,such as the new structural design of the zinc anode,the optimization of the electrolyte composition,the development of new separator materials,and the interface modification between the Zn anode and the electrolyte,etc.Among them,the interface modification strategy between Zn anode and electrolyte has been widely used to suppress the formation of zinc dendrites and side reactions due to its simplicity,efficiency and operability,and to improve the cycle life and charge-discharge performance of zinc anodes.In this paper,a series of functionalized 2D materials and 3D metal-organic framework material interface layers were prepared to regulate the kinetic characteristics of zinc ion transport in view of the serious dendrite problem and other performance defects of the existing zinc anode.The related mechanisms of the inhibition of dendrite,hydrogen evolution reaction and corrosion were explained.It provides valuable theoretical basis and practical experience for the optimal design of zinc anode interface layer and the development of fabric based zinc ion battery in the future.The specific research contents are as follows:（1）Poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT:PSS）modified graphene（PEDOT:PSS/GS）was prepared by a one-step electrochemical exfoliation and functionalized modification method.Then,PEDOT:PSS/GS was coated on the surface of zinc anode to construct a high flux nanochannel interfacial ion modulation layer.The study shows that the PEDOT:PSS/GS interfacial layer regulates the transport of zinc ions through its appropriate nano-flux channel size and surface functional groups,and the introduction of PEDOT:PSS enhances the electrical conductivity and negative charge of graphene,and PEDOT:PSS/GS provides a more uniform surface electric field and homogenizes the distribution of zinc ions at the Zn anode/electrolyte interface to achieve a stable zinc ion deposition/stripping process.At a current density of 1 m A·cm^-2 and an areal capacity of 1m Ah·cm^-2,the cycle life of a symmetric cell with PEDOT:PSS/GS-protected zinc anode（PEDOT:PSS/GS@Zn）was extended to 500 h.The PEDOT:PSS/GS@Zn//MnO₂ full battery assembled with MnO₂@CC cathode can be stably cycled for at least 8000 times at a current density of 1 A·g^-1.（2）Boron nitride nanosheets modified with sodium dodecylbenzenesulfonic acid（S-BN）were prepared by ultrasonic exfoliation of hexagonal boron nitride.Then S-BN was coated on the surface of the zinc anode by spraying technology to construct a high flux of the S-BN interface ion-regulating layer.The results show that the S-BN interface layer mitigates the corrosion of Zn anode by physical isolation,and its nano-scale pore channels make zinc ions flux uniform.Moreover,the abundance of N atoms and sulfonic groups on the surface of S-BN can greatly reduce the concentration gradient of zinc ions and accelerate the transport of zinc ions,thus inhibiting the generation of dendrites and by-products in the process of repeated zinc deposition/stripping.Electrochemical tests show that the cycle life of the S-BN@Zn anode is significantly extended to 2500 h at a current density of 2 m A·cm^-2 and an areal capacity of 2m Ah·cm^-2.Meanwhile,the as-prepared S-BN@Zn anode exhibits high coulombic efficiency（99.5%）.Furthermore,the S-BN@Zn//NVO full cell assembled with Na₂V₆O₁₆?n H₂O（NVO）can still achieve a discharge capacity retention rate of 87.2%after 400 cycles at a current density of 0.1 A·g^-1.（3）UiO-66 and UiO-66-SO₃H metal-organic framework（MOF）materials were synthesized by hydrothermal method,and coated on zinc anode by blade coating method to construct the MOF interfacial layer,respectively.The results show that the interface layer constructed by the two MOF materials has a large amount of open channel structure of ion migration,which contributes to improve the conductivity of zinc ions and guide the uniform distribution of zinc ions on the electrode surface.In addition,the MOF interface layer can also remove the water molecules of[Zn（H₂O）₆]²⁺through partial dessolvation in advance,which inhibited side reactions,corrosion and dendrite growth of zinc anode.In addition,compared with UiO-66,UiO-66-SO₃H has a multi-pore structure and sulfonic acid group,which are more conducive to the uniform distribution of zinc ion flux and promote the desolvation of[Zn（H₂O）₆]²⁺.The UiO-66-SO₃H interfacial layer improve the coulombic efficiency of the zinc anode to 99.2%with more than 600 stable cycles.The UiO-66-SO₃H@Zn anode achieves an ultra-long cycle life of 3000 h at a current density of 2 m A·cm^-2 and an areal capacity of 2m Ah·cm^-2.（4）UiO-66-SO₃H@CC current collector was prepared by coating UiO-66-SO₃H onto carbon cloth（CC）surface by scraping method,and Zn@UiO-66-SO₃H@CC anode was prepared by depositing zinc onto UiO-66-SO₃H@CC by the electroplating method.It was found that UiO-66-SO₃H@CC has a large specific surface area and a hierarchical pore structure,which increases the contact area between the electrolyte and the current collector,realizes the uniform deposition of zinc ions,and improves the ability of Zn@UiO-66-SO₃H@CC anode to inhibit zinc dendrites and side reactions.Electrochemical tests show that the cycle life of the Zn@UiO-66-SO₃H@CC electrode reaches 600 h at a current density of 1 m A·cm^-2 and an areal capacity of 1 m Ah·cm^-2.The flexible Zn@UiO-66-SO₃H@CC//MnO₂ quasi-solid zinc-ion battery was assembled with a flexible MnO₂@CC cathode,which still has a discharge specific capacity of 170 m Ah·g^-1 and a coulombic efficiency of 97.6%after 100 cycles.Moreover,it can still provide stable energy output under conditions of significant bending and local breakage.This excellent flexibility,high environmental adaptability and good safety make Zn@UiO-66-SO₃H@CC//MnO₂ quasi-solid battery viable for smart wearable electronics applications.