Fig. 6: Industrial validation and scale-up of self-breathing electrodes under demanding conditions.

a Long-term stability of PPE-T at 15, 300, and 400 mA cm^–2 (Tests at 15 and 100 mA cm^–2 were conducted in 0.1 mol L^–1 Na₂SO₄, pH = 5.84 ± 0.01, while tests at 200, 300, and 400 mA cm^–2 were carried out in 1 mol L^–1 Na₂SO₄, pH = 6.92 ± 0.06, mass loading of 8 mg cm^–2). b Photograph of a fully integrated, pilot-scale electrolyzer system with four serially connected cells, incorporating electronic, fluidic, and thermal subsystems. c Exploded schematic of the four-cell modular stack. Key components include: 1/17, end plates; 2/5/9/11/16, silicone gaskets; 3, multifunctional bipolar plate enabling both self-breathing and structural support; 4, self-breathing GDE; 6, cathode flow plate; 7, proton-exchange membrane; 8, anode; 10, anode flow plate; 12–14, serially connected electrochemical cells, each assembled from components 3–11; 16, anode current collector. d Internal view of the fluid and thermal management subsystem within the H₂O₂ electrosynthesis platform. The platform comprises anodic and cathodic circulation loops driven by peristaltic pumps, using 5 mol L⁻¹ NaOH (anolyte, pH = 14 ± 0.02) and deionized water (catholyte). Each loop integrates flow, pressure, and level/pH monitoring. Electrolyte temperature is regulated by built-in water-jacket heat exchangers in both reservoirs. A modular power supply is mounted above the unit (not shown). e Long-term stability of the scaled system. Electrolysis was operated at 100 mA cm^–2 under ambient-pressure self-breathing conditions. Each durability test was performed once.