Recently, an unprecedented growth in the internet of things (IoT) is being observed, which is becoming the main driver for the entire semiconductor industry. Reliable maintenance and servicing of the IoT is becoming challenging, knowing that the IoT nodes outnumber the human population by a factor of seven. Energy harvesting (EH) can overcome those difficulties, delivering the energyautonomous IoT nodes to the market. EH converts natural or waste energies (vibrations, heat losses, air flows, light, etc.) into useful energy. This article explores the performance of ZnO nanowires under mechanical actuation to characterize their piezoelectric performance. ZnO nanowires were fabricated using ALD and a subsequent chemical bath growth. AISI 301 steel was used as a substrate of the EH device to better fit the mechanical requirements for the piezoelectric generator. We determined that a thin layer of another oxide below ZnO provides outstanding adhesion. The samples were submitted under repetitive mechanical stress in order to characterize the output piezovoltage for different conditions. They exhibited a piezoelectric signal which was stable after hundreds of actuations. This shows good promise for the use of our device based on ZnO, an Earth-abundant and non-toxic material, as an alternative to the conventional and popular but harmful and toxic PZT. The designed measurement setup demonstrated that a AISI 301 steel substrate coated with ZnO deposited by ALD and grown in a chemical bath has promising performance as a piezoelectric material. Characterized ZnO samples generate up to 80 nJ of energy during 55 s runs under matched load conditions, which is sufficient to supply a modern IoT node.

Aqueous zinc‐ion hybrid supercapacitors (Zn‐HSCs) are promising devices for sustainable and efficient energy storage. However, they suffer from a limited energy density compared to lithium‐ion batteries. This limitation can be overcome by developing novel electrode materials, with covalent organic frameworks (COFs) standing out as a particularly intriguing option. Herein, peri‐xanthenoxanthene (PXX) has been integrated for the first time into a COF scaffold to take advantage of its straightforward synthesis, chemical stability, π‐conjugated backbone, and heteroatom content endowing reversible redox reactions at low potentials. Two novel hexagonal COFs have been designed and synthesized by tethering of a PXX‐diamine unit having a C₂ symmetry with two distinct tris‐aldehydes acting as C₃‐symmetric cornerstones, i.e., triformyl benzene (TFB) and triformylphloroglucinol (Tp), ultimately yielding COF PXX(PhNH₂)₂‐TFB and COF PXX(PhNH₂)₂‐Tp, respectively. As cathodes in Zn‐HSCs, COF PXX(PhNH₂)₂‐Tp exhibits a remarkable specific capacitance, energy, and power densities (237 F g⁻¹, 106.6 Wh kg⁻¹, and 3.0 kW kg⁻¹, respectively), surpassing those of COF PXX(PhNH₂)₂‐TFB (109 F g⁻¹, 49.1 Wh kg⁻¹, and 0.67 kW kg⁻¹). Importantly, both COFs display outstanding long‐term stability, over 5000 charge/discharge cycles, with capacitance retention >92%. These findings underscore the potential of PXX‐based COFs as high‐performance cathode materials for HSCs, thereby offering a promising new avenue for energy storage technologies.