| Abstract: | Flexible photofuel cells (PFCs) have triggered strong scientific interest as promising emerging energy conversion devices for clean power generation due to their potential advantages in low‐cost, simple fabrication, room‐temperature operation, and high conversion efficiency, etc. However, how to enable a PFC with excellent structural flexibility and robustness, and meanwhile with sufficient fuel fed onto electrodes and therefore high power generation remains a significant challenge. Herein, a high‐performance coaxial cable‐shaped PFC device is successfully designed and integrated by employing wet‐spun graphene fiber as the inner cathode, TiO2 nanoparticle‐intercalated graphene spring as the outer photoanode, and a robust polymer gel coated in‐between as the electrolyte separator. The as‐fabricated fiber‐shaped PFC demonstrates effective adsorption of fuel, essential light penetration, and rapid electron/ion transport. Importantly, the fiber cells are sensitive to methane‐based mine gas under sunlight, exhibiting a photocurrent density nearly three orders of magnitude higher than that in air, and excellent and reliable photovoltaic performance with a maximum power density of 0.04 W cm?2 at 0.35 V. This work has shed light not only in using cheap mine gas for efficient power generation, but also on new strategies for design and fabrication of high‐performance PFCs in flexible electronic devices. |
