CO₂ electrolysis allows the sustainable production of carbon-based fuels and chemicals. However, state-of-the-art CO₂ electrolysers employing anion exchange membranes (AEMs) suffer from (bi)carbonate crossover, causing low CO₂ utilization and limiting anode choices to those based on precious metals. Here we argue that bipolar membranes (BPMs) could become the primary option for intrinsically stable and efficient CO₂ electrolysis without the use of scarce metals. Although both reverse- and forward-bias BPMs can inhibit CO₂ crossover, forward-bias BPMs fail to solve the rare-earth metals requirement at the anode. Unfortunately, reverse-bias BPM systems presently exhibit comparatively lower Faradaic efficiencies and higher cell voltages than AEM-based systems. We argue that these performance challenges can be overcome by focusing research on optimizing the catalyst, reaction microenvironment and alkali cation availability. Furthermore, BPMs can be improved by using thinner layers and a suitable water dissociation catalyst, thus alleviating core remaining challenges in CO₂ electrolysis to bring this technology to the industrial scale.

CO ₂电解可实现碳基燃料和化学品的可持续生产。然而，采用阴离子交换膜（AEM）的最先进的CO ₂电解槽存在碳酸氢盐交叉问题，导致CO ₂利用率低，并且将阳极选择限制为基于贵金属的阳极。在这里，我们认为双极膜（BPM）可能成为在不使用稀有金属的情况下本质稳定且高效的CO ₂电解的主要选择。尽管反向和正向偏压BPM都可以抑制CO ₂交叉，但正向偏压BPM无法解决阳极处的稀土金属需求。不幸的是，与基于 AEM 的系统相比，反向偏置 BPM 系统目前表现出相对较低的法拉第效率和较高的电池电压。我们认为，通过重点研究优化催化剂、反应微环境和碱金属阳离子可用性，可以克服这些性能挑战。此外，可以通过使用更薄的层和合适的水离解催化剂来改进BPM，从而缓解CO ₂电解中剩余的核心挑战，从而将该技术推向工业规模。