Ionic Liquid-Softened Polymer Electrolyte for Anti-Drying Flexible Zinc Ion Batteries

作者：Wang, Donghong; Guo, Xun; Chen, Ze; Zhao, Yuwei; Li, Qing; Zhi, Chunyi^*

来源：ACS applied materials & interfaces, 2022, 14(23): 27287-27293.

DOI：10.1021/acsami.2c06793

• polyethylene oxide
• solid polymer electrolyte
• softness
• flexible zinc ion battery
• anti-drying

Using solid polymer electrolytes has been proven to be an efficient strategy to address the metal dendrites and pursuing high-voltage performance. Polyethylene oxide (PEO), as a popular polymer matrix, hardly works for zinc ion batteries due to its poor zinc ionic conductivity and the poor interfacial adhesion. Here, an ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim]OTF), was applied as a plasticizer to tune the room-temperature ionic conductivity and mechanical properties of PEO membrane electrolyte. Additional nanofillers ZnO were utilized to enhance the plasticity and modulus. With an optimized composition, the membrane exhibits a high modulus and soft mechanics, which can facilitate the reversible stripping/plating of Zn without formation of Zn dendrites. The optimized polymer electrolyte achieved an ionic conductivity of 2.3 x 10(-3) S cm(-1) at room temperature with a softness of 5.1 mm. By applying the resulted soft membrane electrolyte for a Zn-MnO2 battery, a capacity of 137 mAh g(-1) is achieved at 30 mA g(-1) even without the contribution from H+. Such an electrolyte also works for Prussian blue analogue cathodes. Importantly, the addition of [Emim]OTF can enhance the soft contact with the electrodes, and a stable output is delivered under severe deformations for the assembled flexible devices.