Capillary reinforcement induced fabrication of cotton fiber array based hydro-electric generator for enhanced voltage output

Hydro-electricity generator (HEG) that uses ubiquitous environmental water molecules as an energy source could offer compelling advantages including minimal pollution and low cost. This work develops an effective, extendable, and stable HEG array by using a hierarchically structured carbon black/phytic acid@cotton fiber column (CB/PA@CFC) composite. The device achieves high energy conversion efficiency through rational structural optimization. Specifically, the CFC serves as microporous container for accommodating PA molecular and CB particles. The existing PA fully optimizes inner pore structure of the CFC via chemical grafting to improve capillary role and enhance its hydrophilicity, while it also provides abundant H + through PA dissociation. Besides, the introducing CB particles effectively reinforces the conductivity of the CFC by establishing continuous conductive pathways for efficient electron conduction. Under 65 % relative humidity, a single HEG delivers an impressive open-circuit voltage (Voc) of 1.07 V and a short-circuit current (Isc) of 1.42 mA, reaching a power density of 0.94 mW/cm 3 . Such high performance stems primarily from capillary-driven ion diffusion gradients and enhanced electrical conduction (4.1 × 10 −2 S/m), which synergistically amplify the inner electric field. Furthermore, the integrated HEG module constructed by connecting 5 × 3 array in series, achieves a stable output voltage of 10.5 V, sufficient to power a small water electrolysis device for hydrogen production.