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

Abstract

Water dissociation (WD) with bipolar membranes (BMs) is becoming 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 satisfying the needs of emerging energy/mass conversion devices. Based on numerical simulations, we propose here a stepwise strategy to construct a BM with a 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 the longest stability (1100 hours) can be achieved. The introduction of covalent interfaces 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.