Flexible Leaf‐Like Fuel Cell From Plasmonic Janus Nanosheet

Abstract The ability to design leaf‐like fuel cells may enable artificial tree‐like electricity generators to power home appliances. However, the existing fuel cells are typically rigid and heavy in 3D layout. Here, this study reports on a flexible, lightweight, and 2D leaf‐like methanol fuel cell based on conductive sponge‐supported plasmonic Janus nanosheet. The nanosheet is made from self‐assembled gold nanocube (Au NC) arrays, followed by spiky growth at one side and ≈5 nm palladium coating. Such designed nanosheets can simultaneously offer three functionalities: high electrochemically active surface area, chemical catalysis, and plasmon enhancement. This study finds that light‐enhanced electrochemical performance can be retained over 90% even when being bent or twisted. Further integration of the Janus nanosheets with highly conductive gold nanowire sponges allowed for fabricating a flexible leaf‐like fuel cell with a thickness of 3 mm and a weight of 0.1 g. The flexible leaf can generate a power of 8.93 mW cm − 2 under light irradiation with less than 10% performance deterioration even under 360 ° twisting and 180 ° bending. In a tree‐like design, 95% power retention is achieved under natural omnidirectional light irradiation and wind‐induced deformation.