Robust triboelectric energy harvesters engineered from electrochemically deposited films of HKUST-1 polycrystals

Triboelectric nanogenerators (TENGs) offer a potential power source for compact electronics and self-powered portable devices, with increasing interest in integrating metal-organic frameworks (MOFs) due to their tunable physical and chemical properties. However, the direct incorporation of MOF powders in TENG is hindered by their weak and unstable attachment to the underlying conductive substrates. Herein, we show that electrochemical MOF deposition offers a facile approach to deposit hydrophilic HKUST-1 films on a copper electrode, yielding a robust tribopositive layer after a growth time of 2 h. When this surface was impacted against a tribonegative layer such as Kapton under contact-separation mode, the optimal output of the TENG device reached the highest voltage output of  ~99 V with a power density of 771.8 ± 0.3 mW m^-2. The device exhibits extended stability, with a negligible voltage decay under ambient environment and exposed to relative humidity from 10% to 70%. This study demonstrates a feasible strategy to generate mechanically resilient MOF-based TENGs with reproducible output for real-world environmental conditions.