Preparation And Performance Study Of Flexible Yarn Zinc-ion Batterie

At present,electronic devices are becoming flexible,miniaturized and multifunctional in accordance with people’s requirements.In energy storage equipment,compared with commonly used lithium-ion batteries,zinc-ion batteries have the characteristics of low cost and high safety,and are considered to be the most advantageous and promising batteries in the field of battery energy storage in the future.Based on this,in order to meet the growing demand for flexible wearable products,a one-dimensional yarn-like flexible zinc ion battery was prepared using carbon fiber as the substrate.In this paper,electrospinning and in-situ polymerization of polypyrrole（PPy）are used to prepare conductive yarns,and Zn negative electrodes and Mn O₂positive electrodes are prepared by electrodeposition and dip coating methods.Secondly,PAM gel electrolyte was prepared by free radical polymerization to assemble the yarn zinc ion battery.Finally,in order to improve the cycle stability of the yarn battery,PAM hydrogel was modified by introducing carboxymethyl cellulose（CMC）to form a double network structure.The specific research content is as follows:（1）CPP yarn was prepared by electrospinning polyacrylonitrile（PAN）and in-situ polymerization of polypyrrole（PPy）,and then CPP@Zn yarn negative electrode was prepared by electrochemical deposition,CPP@Mn O₂ yarn positive electrode was prepared by dip coating.Determine the optimal process parameters.Under the three-electrode system,after repeated charge and discharge cycles,the CPP@Zn yarn negative electrode can still maintain 87.76%of the original specific capacitance,and the CPP@Mn O₂ yarn positive electrode still has a capacity retention rate of 89.76%.（2）In order to assemble the yarn-like battery with the yarn electrode,the PAM hydrogel prepared by free radical polymerization has excellent tensile properties（up to1600%tensile deformation）,thermal stability（higher thermal decomposition temperature）and water absorption properties（1476.73%water absorption）.PAM-based gel electrolyte also has excellent ionic conductivity,which can reach 4.24×10^-2S/cm,and the decomposition voltage of PAM-based gel electrolyte is 2.525V through electrochemical window test;Electrochemical tests were performed on the assembled PAM-based yarn battery.The yarn battery has excellent rate performance and cycle stability.When the current density is 1 m A cm-1,its length specific capacitance can reach 146.88μAh cm^-1,It can maintain 64.98%after 100 cycles,and it has good cycle stability even under different bending angles and repeated bending conditions.（3）In view of the poor cycle stability of PAM-based yarn batteries,the PAM hydrogel was modified by introducing carboxymethyl cellulose（CMC）to form a double network structure.The obtained CMC/PAM hydrogel has better tensile properties（2700%tensile deformation）and water absorption（1869.74%water absorption）than PAM,and its thermal stability is the same as that of PAM hydrogel.CMC/PAM gel electrolyte has higher ionic conductivity than PAM gel electrolyte.Through electrochemical window test,the decomposition voltage of CMC/PAM hydrogel electrolyte is 2.635V;Electrochemical tests were performed on the assembled CMC/PAM-based yarn battery.The yarn battery has better rate performance and cycle stability than the PAM-based yarn battery.When the current density is 1 m A cm^-1,its length is greater than the capacitance.It can reach 170.23μAh cm^-1,and it can maintain73.14%after 100 cycles.Even under different bending angles and repeated bending conditions,the cycle stability is better than that of PAM-based yarn batteries.The research in this paper can provide new ideas for the development of flexible energy storage equipment.