Chemically interlocked bipolar membrane achieving stable water dissociation for high output ammonia electrosynthesis

Water dissociation (WD) with bipolar membranes (BMs) becomes the most effective solution for optimizing pH or ionic species incompatibility of anolyte/catholyte in electrochemical devices; however, available BMs always suffer from sluggish WD kinetics and structural delamination, thus hardly satisfy the emerging energy/mass conversion devices. Instructed by numerical simulation, we here propose a stepwise strategy to construct a BM with stable C-C covalent interlocking interlayer (CIBM) to solve the dilemma, through which physical binding strength and ionic transportation rate are exponentially enhanced. Due to this covalent design, an unprecedented WD performance at high current (1.17 V at 1000 mA cm-2) and an longest stability (1100 hours) can be achieved. The introducing of covalent interface also successfully realized a continuous BM NH3 electrosynthesis with high efficiency, low energy consumption and state-of-the-art yield (70.9 mg cm-2 h-1) from 2000 ppm NO3-, providing innovative design principles for emerging ampere-level BM electrochemical devices.