Remarkable improvement of MOF-based triboelectric nanogenerators with strong electron-withdrawing groups

Abstract

A metal-organic framework (MOF) with extraordinary designability and functionality has been reported as a promising material for triboelectric nanogenerators (TENGs) to harvest energy from the ambient environment. However, the limited performance of current MOF-TENGs severely restricts their further development. Herein, we tackle this challenge by introducing strong electron-withdrawing groups. We designed and synthesized UiO-66–4F with Zr6O4(OH)4 and tetrafluoroterephthalic acid (TFA) ligands. The four F atoms in a TFA ligand with strong electron negativity accounts for a huge improvement of the MOF-based TENGs, as demonstrated by experiments on different contrasting materials, and further examined with density functional theory calculations to reveal the underlying mechanism. Thanks to the enhanced surface property and strong electron-withdrawing capability enabled by introducing the UiO-66–4F, the UiO-66–4F@PDMS TENG generates a power density that is 77.5 times higher than that of a PDMS TENG, and the voltage output reaches a record high at 937 V in MOFs-based TENGs. The UiO-66–4F@PDMS TENG also exhibits high flexibility and good transparency, and is revealed to charge commercial capacitors and power 354 commercial LEDs. Our work provides a strategy to explore the fabrication and application of high-performance MOF-based TENGs.