Extracting the Gibbs free energy from natural water salination, a.k.a. the blue energy, has attracted a long-standing, global interest. While pressure-retarded osmosis (PRO) and reverse electrodialysis (RED) are by far the most studied methods for such a purpose, the concept of using the capacitive electrode response for blue energy harvesting has been shown to offer unique advantages. Despite that porous electrodes are predominately used in capacitive methods, the role of pore properties in energy extraction remains unclear. Here we show that the distribution of the nano-sized pores in an electrode imposes a profound impact on the electrode capacitive response under a salinity gradient. Such a pore-size effect can be sufficiently strong that leads to structural changes of the electric double layer, resulting in highly efficient extraction of the Gibbs free energy. We demonstrate that a device fabricated with carbon electrodes with significantly different nanopore distributions can generate a high power density without membranes or an external charge source.

从天然水的盐分提取中提取吉布斯自由能，也就是蓝色能量，引起了全球的长期关注。到目前为止，虽然压力滞后渗透（PRO）和反电渗析（RED）是研究最多的方法，但已证明将电容电极响应用于蓝色能量收集的概念具有独特的优势。尽管在电容性方法中主要使用多孔电极，但孔性能在能量提取中的作用仍不清楚。在这里，我们表明，在盐度梯度下，电极中纳米孔的分布对电极电容响应产生了深远的影响。这样的孔径效应可能足够强，导致双电层的结构发生变化，导致吉布斯自由能的高效提取。我们证明了用具有显着不同的纳米孔分布的碳电极制造的设备可以产生高功率密度而无需膜或外部电荷源。