Preparation And Performance Research Of Flexible Antifreeze Supercapacitor Based On Gly-Mo

With the development of wearable devices towards lightness and flexibility,the demand for flexible energy storage devices is increasing.Currently,polymer hydrogels are widely used in flexible devices due to their excellent mechanical performance.However,wearable electronics used at low temperatures inevitably freeze and lose their original mechanical and conductivity properties,making the development of supercapacitors that can maintain flexibility and energy storage performance at sub-freezing temperatures an urgent issue.Designing anti-freezing supercapacitors requires consideration of issues such as structure,electrode materials and electrolytes,presenting new challenges for the development of flexible energy storage technology.In this study,PPy/（Gly-Mo）_X electrode materials were prepared by introducing organic solvent glycerol（Gly）into inorganic molybdenum salt complexes during the in-situ polymerization process of polypyrrole（PPy）.The effect of Gly-Mo content on the energy storage performance of PPy/（Gly-Mo）_X electrode materials was studied using cyclic voltammetry,constant current charge-discharge,and electrochemical impedance spectroscopy.The results showed that the addition of active substance Gly-Mo increased the energy storage performance of the electrode.At a current density of0.5 A g^-1,the specific capacitance of PPy/（Gly-Mo）_8.7 electrode material was 499.8 F g^-1.Using organic hydrogels as electrolytes is an effective strategy to enhance the anti-freeze performance of supercapacitors.In this study,Gly-Mo was introduced into polyvinyl alcohol（PVA）,benefitting the crosslink of PVA network.The obtained PVA/（Gly-Mo）_X organic hydrogel was used as electrolytes for supercapacitors.The Gly-Mo solvent was embedded into the three-dimensional structure of PVA,which can inhibit water from freezing below 0°C and improve the mechanical properties of organic hydrogels.PVA/（Gly-Mo）₈ had a more than 75%transmittance in the visible range,a weight retention rate of approximately 70%after being placed at 50°C for 24hours,and an ion conductivity of 8.6 m S cm^-1 at-40°C.To enhance the ion transport of supercapacitors,an all-in-one supercapacitor was prepared using PVA/（Gly-Mo）₈ electrolyte and PPy/（Gly-Mo）_8.7 electrode material by in-situ polymerization.Under a power density of 80μW cm^-2 at room temperature,it provided a high energy density of 17.5μWh cm^-2 and could drive an LED light in series to meet certain energy supply requirements.At-40°C,the specific capacitance was maintained at 63.4%of that at room temperature.In addition,over five reversible temperature cycles,the specific capacitance of the supercapacitor remained almost unchanged,indicating its superior stable anti-freeze performance.Meanwhile,the device can work under extreme conditions.In the punching experiment,the capacitance retention rate of the device within 300-900 holes cm^-2 was above 120%.After being bent 400 times at a 90°angle,the specific capacitance retention rate remained at 68.1%.After working at 50°C for 4 hours,the capacitance retention rate was 54.3%.In conclusion,the device exhibits excellent electrochemical performance and flexible anti-freeze characteristics,and has great development prospects.