Application Of High Performance Dual Network PAM/P123 Gel Electrolyte In Rechargeable Zn-MnO₂ Batteries

Flexible wearable devices are at the forefront of next-generation electronic devices.In which the most important components is matching energy storage and conversion system as a power source,such as flexible lithium-ion batteries（LIBs）,supercapacitors（SCs）,solar cells,and micro fuel cells,etc.In recent years,exploring how to manufacture more suitable and effective electrolyte materials,optimizing battery configuration and structural design,developing flexible power supplies with better electrochemical performance,and finally realizing the integration of flexible electronic products has become a research hotspot.In the extensively researched battery system,water-based zinc ion batteries have the characteristics of high energy density,good rate performance,low price of positive and negative materials,environmentally friendly electrolytes,high safety,simple assembly methods,and low manufacturing costs.They have obvious advantages in flexible wear and safe energy storage.Aiming at the problems of low ion conductivity,poor mechanical properties,poor weather resistance,and the safety and electrochemical stability of the traditional electrolyte encapsulation caused by the existing zinc ion electrolytes,this paper proposes a free radical polymerization to prepare PAM/P123 double network gel electrolyte for zinc ion batteries.At the macro level,the thermal stability and mechanical properties of the hydrogel are systematically studied.At the micro level,the bonding method and microstructure of the hydrogel are explored.Finally,a series of PAM/P123-2 gel electrolytes with the best performance are used to assemble button and soft-pack batteries for electrochemical analysis.This research is expected to be widely used in various flexible battery devices.The main research contents of this paper are as follows:（1）The PAM/P123 series double network hydrogel electrolyte was proposed and synthesized by free radical polymerization,and it was confirmed by Fourier transform infrared spectroscopy that a new double network structure hydrogel was formed by cross-linking.The surface and cross-sectional morphology of the gel were analyzed by SEM.By calculating the swelling rate,the influence of the added amount of P123 on the liquid absorption performance of the gel was analyzed,and the thermal stability of PAM/P123 series hydrogels was compared with PAM hydrogels by TG and DSC.Finally,through tensile stress-strain and cyclic compression loading and unloading tests,the mechanical properties are further compared,and the experimental basis is provided for the actual use of the flexible electrolyte.（2）Proposed and realized a flexible zinc-ion battery with nano-flower-shaped Mn O₂/C as the cathode,Zn foil as the anode,and PAM/P123-2 double network hydrogel as the electrolyte,assembled into a button battery（CR2032）,and performed electrochemical test.Experiments show that the highest conductivity of PAM/P123 dual network electrolyte at 0°C is 36.2 m S cm^-1,and the conductivity is higher than that of pure PAM electrolyte in the range of-30°C～65°C.Moreover,the conductivity of PAM/P123-2 from 0°C to-20°C is higher than the previously reported aqueous electrolyte for zinc ion batteries.The rate performance of the flexible quasi-solid Zn/Mn O₂ battery prepared by using PAM/P123-2 gel electrolyte is better than that of the PAM hydrogel battery,and the cyclic charge and discharge test is carried out at 0°C and 0.6 A g^-1 charge and discharge current density.The first Coulomb efficiency can reach 97.24%,charging and discharging are stable,and the capacity retention rate reaches82.39%after 1000 cycles.（3）The PAM/P123-2 hydrogel electrolyte is used in Zn/Mn O₂ soft-pack batteries.The charge-discharge current density of 0.6 A g^-1 is used for cyclic charge-discharge test at room temperature.After 500 cycles,the capacity retention rate reaches 85.40%.The soft-pack battery can light up a small tungsten filament bulb with a rated voltage of 1.5 V after being charged.Two soft-pack batteries in series can light up an LED lamp with a rated voltage of 3V.PAM/P123-2 hydrogel is expected to replace the electrolyte in flexible soft-pack batteries and solve the problem of electrolyte leakage caused by the imperfect aluminum-plastic film packaging of soft-pack batteries due to good electrochemical stability and high swelling rate.