Ion transport in nanoconfinement differs from that in bulk and has been extensively researched across scientific and engineering disciplines^1,2,3,4. For many energy and water applications of nanoporous materials, concentration-driven ion diffusion is simultaneously subjected to a local electric field arising from surface charge or an externally applied potential. Due to the uniquely crowded intermolecular forces under severe nanoconfinement (<2 nm), the transport behaviours of ions can be influenced by the interfacial electrical double layer (EDL) induced by a surface potential, with complex implications, engendering unusual ion dynamics^5,6,7. However, it remains an experimental challenge to investigate how such a surface potential and its coupling with nanoconfinement manipulate ion diffusion. Here, we exploit the tunable nanoconfinement in layered graphene-based nanoporous membranes to show that sub-2 nm confined ion diffusion can be strongly modulated by the surface potential-induced EDL. Depending on the potential sign, the combination and concentration of ion pairs, diffusion rates can be reversibly modulated and anomalously enhanced by 4~7 times within 0.5 volts, across a salt concentration gradient up to seawater salinity. Modelling suggests that this anomalously enhanced diffusion is related to the strong ion–ion correlations under severe nanoconfinement, and cannot be explained by conventional theoretical predictions.

纳米限制中的离子传输与散装中的离子传输不同，并且已在科学和工程学科^{1,2,3,4 中}进行了广泛研究。对于纳米多孔材料的许多能量和水应用，浓度驱动的离子扩散同时受到由表面电荷或外部施加的电位引起的局部电场的影响。由于在严重的纳米限制 ( < 2 nm)下独特的拥挤的分子间力，离子的传输行为会受到由表面电位引起的界面双电层 (EDL) 的影响，具有复杂的影响，产生不寻常的离子动力学^{5,6 ,7}. 然而，研究这种表面电位及其与纳米限制的耦合如何操纵离子扩散仍然是一个实验挑战。在这里，我们利用基于分层石墨烯的纳米多孔膜中的可调纳米限制来表明亚 2 nm 限制离子扩散可以通过表面电位诱导的 EDL 强烈调节。根据电位符号、离子对的组合和浓度，扩散速率可以在 0.5 伏特内可逆地调节和异常增强 4~7 倍，跨越盐浓度梯度直至海水盐度​​。建模表明，这种异常增强的扩散与严重纳米限制下的强离子-离子相关性有关，无法用传统的理论预测来解释。