Upcycling Bamboo Waste into a Water Evaporation Induced Generator with Sustained High‐Output Energy Density for Self‐Powered Sensors

Evaporation‐induced power generation has garnered significant attention as an emerging energy harvesting strategy. However, conventional water evaporation‐driven energy harvesting technologies rely on intricate nanostructures, which suffer from complex fabrication processes, high costs, and scalability challenges. This paper develops a novel Bamboo‐based Evaporation‐Induced Generator (BbEIG) using discarded disposable bamboo chopsticks. The inherent porous structure of bamboo enables efficient thermal energy harvesting from the environment through water evaporation and its subsequent conversion into electricity. At room temperature, the BbEIG achieves an open‐circuit voltage of 0.36 V and a short‐circuit current of 10 µA, demonstrating stable power output for 12 000 s. The power density of BbEIG is 2 µW cm −2 , which is currently a record. The device can charge a 10 000 µF capacitor to its saturation voltage within 40 min. By connecting 18 BbEIG units in series, an open‐circuit voltage of 7 V is achieved, sufficient to illuminate a light‐emitting diode (LED). Furthermore, the integrated system successfully powers a commercial temperature‐humidity sensor, enabling continuous operation. The results of this work show that the combination of disposable bamboo chopsticks and evaporation‐induced power generation provides a sustainable green energy supply strategy for distributed sensing networks.