Electrolyte-filled subnanometre pores exhibit exciting physics and play an increasingly important role in science and technology. In supercapacitors, for instance, ultranarrow pores provide excellent capacitive characteristics. However, ions experience difficulties in entering and leaving such pores, which slows down charging and discharging processes. In an earlier work we showed for a simple model that a slow voltage sweep charges ultranarrow pores quicker than an abrupt voltage step. A slowly applied voltage avoids ionic clogging and co-ion trapping—a problem known to occur when the applied potential is varied too quickly—causing sluggish dynamics. Herein, we verify this finding experimentally. Guided by theoretical considerations, we also develop a non-linear voltage sweep and demonstrate, with molecular dynamics simulations, that it can charge a nanopore even faster than the corresponding optimized linear sweep. For discharging we find, with simulations and in experiments, that if we reverse the applied potential and then sweep it to zero, the pores lose their charge much quicker than they do for a short-circuited discharge over their internal resistance. Our findings open up opportunities to greatly accelerate charging and discharging of subnanometre pores without compromising the capacitive characteristics, improving their importance for energy storage, capacitive deionization, and electrochemical heat harvesting.

电解质填充的亚纳米孔展现出令人兴奋的物理特性，并在科学技术中发挥着越来越重要的作用。例如，在超级电容器中，超细孔可提供出色的电容特性。然而，离子在进入和离开这些孔时遇到困难，这减慢了充电和放电过程。在较早的工作中，我们显示了一个简单的模型，即缓慢的电压扫描比狭窄的电压阶跃更快地为超细孔充电。缓慢施加的电压避免了离子阻塞和共离子俘获（当施加的电位变化太快时会发生此问题），这会导致动态响应缓慢。本文中，我们通过实验验证了这一发现。在理论考虑的指导下，我们还开发了非线性电压扫描，并通过分子动力学模拟证明它可以比相应的优化线性扫描更快地给纳米孔充电。对于放电，我们通过模拟和实验发现，如果我们反转施加的电势然后将其扫至零，则其孔内的电荷损失比短路放电导致的内电阻损失要快得多。我们的发现为在不损害电容特性的前提下大大加速亚纳米孔的充放电提供了机会，从而提高了它们在能量存储，电容去离子和电化学吸热中的重要性。