Effect of adding ionic liquid into polydimethylsiloxane on the output performance of triboelectric nanogenerator

Adding 1-butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (BMIM-TFSI), an ionic liquid, to polydimethylsiloxane (PDMS) films significantly enhances the output of triboelectric nanogenerators (TENGs). In a TENG using contact and separation between the composite film and an aluminum (Al) plate, incorporating 0.1 vol% of BMIM-TFSI more than doubled the output voltage achieved compared to a pure PDMS film. To understand the cause of this improvement, composition analysis around the surface of the composite polymer film was conducted before and after tapping. We found that BMIM-TFSI molecules segregated around the surface after tapping. It is considered that the polarization of the BMIM-TFSI molecules enhances the output performance of TENGs by superimposing on the surface charges generated at the PDMS/Al interface.