To improve the ionic conductivity and electrochemical performance,a cement-based composite electrolyte with high ionic conductivity and good mechanical strength was synthesized by using room temperature ionic liquid 1-butyl-3-methylimidazole bromide(BMIMBr)as redox active additive,which can be applied to construct structural supercapacitor.The results show that the ionic conductivity of cement-based composite electrolyte containing 20％(mass fraction)BMIMBr reaches the highest value of 35.91 mS·cm-1.BMIMBr can provide Br-which can produce reduction reactions and increase the number of free ions,which is beneficial for ion transport in electrolyte and obtains higher specific capacitance.The structural supercapacitor shows a high specific capacitance of 20.07 F·g-1 at a current density of 0.05 A·g-1.After 1 000 cycles of galvanostatic charge-discharge,the capacitance retention rate reaches 83.6％and coulomb efficiency is 97.56％,demonstrating an excellent cycle lifespan.
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