Breaking the trade-off between hydroxide ion conductivity and gas-blocking capability in porous composite membranes to boost advanced alkaline water electrolysis

The trade-off between hydroxide ion conductivity (i.e., area resistance) and gas-blocking capability (i.e., bubble point pressure) in the organic–inorganic porous composite membranes critically hinders the development of alkaline water electrolysis (AWE) technology. Herein, it firstly demonstrates the inherent trade-off relationship based on the validated experimental database. To decouple this intrinsic relationship, the dual-functional material introduction strategy is proposed by replacing ZrO 2 with NiFe-LDH nanoparticles. The results indicate that it achieves decoupled regulation of membrane performance via a fast OH − conduction mechanism (i.e., the Grotthuss mechanism) induced by NiFe-LDH, without varying the pore microstructure. It reaches a 50% area resistance reduction with high bubble point pressure (~17 bar) unchanged. Besides, it reveals that the levelized cost of hydrogen using the membrane is as low as $0.82/kg H 2 , meeting the US DOE target. It provides a promising technical solution for the design of high-performance porous composite membranes, boosting advanced AWE technology. • This work first demonstrates the trade-off between area resistance and bubble point pressure in AWE membranes via 115 samples. • NiFe-LDH achieves dual control of OH − conduction and pore microstructure, improving membrane performance. • L x Z y -PSF-n membranes cut area resistance by 50% without lowering the bubble point pressure (17 bar), proving performance decoupling. • The resulting membrane delivers 1.77 [email protected] A·cm −2 for 680 h and $0.82/kg H 2 , showing strong potential.