Controllable design of high-efficiency triboelectric materials by functionalized metal–organic frameworks with a large electron-withdrawing functional group

Triboelectric nanogenerator (TENG) can directly convert mechanical energy into electric energy. However, the triboelectric materials are limited to the triboelectric series. Here, for the first time, we choose the isostructural UiO-66-X (X = H, NH₂, NO₂, and Br) family as triboelectric materials to investigate the underlying relationships between different functional groups and the triboelectric performance of TENG. Unlike traditional triboelectric material organic polymers, metal–organic frameworks (MOFs) can be oriented design synthesis and functionalized with various functional groups. The results demonstrate that the largest output voltage and current are from UiO-66-NO₂ TENG, and are about 23.79 V and 0.29 μA, which are 3.19 and 4.14 times over that of the UiO-66 TENG, respectively. The working mechanism of the MOF TENG was discussed in depth through experiments and theoretical calculations. This work proves a novel strategy to obtain high output properties by functionalized MOFs with large electron-withdrawing functional groups and promising guidance for the choice of high-efficiency triboelectric materials.