Utilizing sugarcane as green transpiration-driven generator for efficient electricity harvesting from seawater

Transpiration-driven electrokinetic generators are fast emerging as an autonomous energy harvesting technology due to their spontaneous and continuous power generation at mild conditions. While biomass materials have enabled the construction of green transpiration-driven generators, current designs are impeded by problems such as low power production, narrow operation conditions, and difficulty in large-scale fabrication. Herein, we mitigate these limitations by creating an efficient, evaporation-driven generator using sugarcane as a unique structural template. Notably, sugarcane comprises of an extensive network of one-dimensional capillary channels that is ideal to promote directional transpiration and streaming processes for power generation. Using seawater as an electrolyte solution, our sugarcane-based generator allows efficient harvesting of electrical energy at room temperature with a high open-circuit voltage (VOC, ~ 470 mV), short-circuit current (ISC, 8.2 μA), and maximum output power (36.7 nW/cm2). These power generation performances are at least 35% better than conventional methods that employ deionized water as wetting liquid, and also excel over wood-based generators and other designs by up to 2-fold and 120-fold, respectively. The sugarcane-based generators can also be connected in series or parallel to modulate their electrical outputs, thereby providing a reliable energy source to swiftly power modern electronic devices. By utilizing sugarcane as a green biomaterial and seawater as an abundant energy feedstock for power generation, our unique approach creates valuable insights to expedite the progress towards distributed, sustainable energy harvesting and the practical valorization of biomass into functional materials.