Metal–organic framework coated porous structures for enhanced thermoelectric performance

•Passive and ecological thermal management through metal-organic framework coatings.•Desorption and radiation lead to an ≈300% increase in the thermoelectric power.•Further enhancement possible through optimized design and operation.•Numerical optimization to determine the optimal enhancement scenario. Self-powered sensors/transmitters can be operated by thermoelectric generators if the temperature difference across the device is maximized. Here, we demonstrate a novel strategy to increase the overall thermoelectric conversion efficiency near room temperature (≈30 °C) through enhancement of the heat transfer between the thermoelectric generator and the atmosphere by utilizing the latent heat of atmospheric water, radiative cooling, and an enhanced surface area. To maximize the sorption and emissivity, we coat porous copper substrates with metal-organic frameworks. Thermoelectric generators interfaced with these heat sinks exhibit a 50%–70% enhancement in the overall heat transfer coefficient owing to the increased surface area due to particle binding and the material properties of metal–organic frameworks. Furthermore, proof-of-concept experiments reveal an ≈100% increase in the total electromotive force generated by the thermoelectric generator within 30 min. Our study not only introduces a novel method to enhance the thermoelectric conversion efficiency, but also provides physical insight into the link between sorption and thermal processes.