Bio-Derived Wood-Based Gas Diffusion Electrode for High-Performance Aluminum-Air Batteries: Insights into Pore Structure

Gas reactant transport plays a crucial role in various gas-consumption reaction-based electrochemical devices, but the pivotal performance limitation still centers on gas diffusion electrodes (GDEs). To this end, natural cross-cut wood to prepare GDEs for aluminum-air batteries is introduced by utilizing the ordered structure with microchannels. With cobalt-nitrogen co-doped carbon nanotubes as the oxygen reduction reaction catalysts grown inside the channels of carbonized wood slice and wettability gradient modification, cherry-based GDE achieves higher power density (267 vs. 236 mW cm-2) than the commercial carbon fiber paper-based electrode. By bridging the identified characteristics of pore structure via deep-learning image recognition technology with the permeability of other three typical kinds of (ash, pine, and oak) wood-based GDEs, it is revealed that the ratio of effective porosity to the average pore size is key to the performance. This work demonstrates the feasibility of bio-derived wood-based materials for fabricating high-performance GDEs and provides insights into pore structure for the rational design of structured electrodes. Bio-derived wood slices with aligned vertical pore structures are prepared as high-performance gas diffusion electrodes for aluminum-air batteries, with cobalt-nitrogen co-doped carbon nanotubes as catalysts and gradient wettability modification, achieving superior power density of 267 mW cm-2 than commercial carbon fiber paper electrode, which is attributed to the considerable ratio of effective porosity to the average pore size.image