Application of Cyclodextrin Supramolecular Gel Electrolyte Based on Ionic Liquids in Zinc Ion Batteries
摘要
The preparation of ionic liquid gel electrolyte can reduce the occurrence of side effects and extend battery life. In the DMSO-ILZE electrolyte composed of DMSO, 1-ethyl-3-methylimidazole tetrafluoroborate (EMIMBF4) and Zn(BF4)2, the supramolecular gelator β-cyclodextrin (β-CD) was added, and then a gel electrolyte (CD-ILZE) for zinc-ion batteries was prepared through host-guest interaction between β-CD and DMSO-ILZE electrolyte. The gel electrolyte has good conductivity between −30 and 80 °C, which is found by fitting the Arrhenius equation that the gel electrolyte satisfies the liquid law within this temperature range. In addition, the supramolecular gel electrolyte can effectively decrease hydrogen evolution corrosion and the formation of zinc dendrites. Compared with the battery prepared by DMSO-ILZE electrolyte (about 1 100 h), the prepared Zn∥Zn battery exhibits a more stable cycle (over 2 800 h) at a current density of 0.5 mA·cm−2. At 0.1 A·g−1, the prepared Zn∥V2O5 gel electrolyte cell has a capacity of 30 mAh·g−1 and a capacity retention rate of 85.17% after more than 1 500 cycles. The CD-ILZE supramolecular gel electrolyte can inhibit the formation of hydrogen evolution corrosion and zinc dendrites, and improve the cycling performance of the battery.