A self-breathing electrode enabled by interface regulation and gradient wettability engineering for industrial H2O2 electrosynthesis.

High-performance gas diffusion electrodes (GDEs) are essential for electrochemical H2O2 production, yet conventional catalyst layers (CLs) suffer from PTFE-fused encapsulation and disordered pores that create mass-transport bottlenecks and suppress three-phase interface (TPI) formation. Here, we introduce a non-fused particulate-packed catalyst/binder interface and elucidate the mechanisms governing TPI formation through 3D reconstruction and mesoscale LBM analyses. Guided by these insights, we construct a hierarchical gradient CL with ordered porosity and tunable wettability contrast, and multiscale simulations together with in-situ breakthrough and microfluidic experiments confirm capillarity-driven electrolyte displacement and directional self-transport of H2O2, enabling stable Faradaic efficiencies >85% at 300 mA cm-2 for 300 h. We further develop a 400 cm2 four-unit self-breathing flow-through stack integrating thermal, fluidic, and electronic systems for continuous, oxygen-free, low-cost H2O2 generation. This work offers a fundamental design framework for advanced GDEs and demonstrates a milestone integrated self-breathing H2O2 electrosynthesis system with commercial viability.