Comparing Advanced Bipolar Membranes for High-Current Electrodialysis and Membrane Electrolysis
Olivia T. Vulpin, James B. Mitchell, Lihaokun Chen, Jeonghoon Lim, Sayantan Sasmal, Nathan G. Price, Sam R. Jarvis, Shannon W. Boettcher
Abstract
Advanced bipolar membranes (BPMs) with low water-dissociation overpotential (η wd ) may enable new electrochemical technologies for electrolysis, fuel cells, acid–base synthesis, brine remediation, lithium-battery recycling, and cement production. However, these advanced BPMs have only been demonstrated in BPM water electrolysis (BPMWE) configurations where the BPM is under static compression by the porous-transport layers. It is important to study these BPMs in applications like electrodialysis where large degrees of static compression are not possible. We present a BPM electrodialysis (BPMED) platform to measure water-dissociation overpotential (η wd ) and compare BPMWE and BPMED systems. We show advanced BPMs with half the η wd compared to commercial BPMs for BPMED while maintaining ∼90% current efficiency from 0.05–0.5 A cm –2 . The BPMED η wd values are, however, about 0.2 V higher at 0.5 A cm –2 than those for BPMWE. Regardless, these results show that BPMs developed and optimized in BPMWE applications are well-suited for next-generation high-current-density BPMED technologies.