For salinity gradient energy harvesting, membrane ion selectivity plays an important role, which is often qualitatively analysed via the electric double layer (EDL) overlapping degree in conventional studies. However, the degree of EDL overlapping is hard to be quantitatively evaluated. Here, we systematically analyze the synergy relations between physical vectors that determining the energy conversion process to quantitatively illustrate the EDL overlapping degree and ion selectivity. Three synergy angles are proposed to describe the synergy relations between the ion diffusion and the electrostatic migration driven forces. A synergy degree parameter is further defined, which could offer a quantitative way to analyze the cation transference number under different concentration ratios, channel length, and asymmetric channel geometries. In addition, an alternative way to use large size nanochannels to efficiently harvest the salinity gradient energy is developed by employing nanowire blockers. The inserted nanowire blocker can significantly enlarge the synergy degree parameter, thus to enhance the ion selectivity, upgrade the membrane potential, and bring a significant augment on the electric power and energy conversion efficiency. This study offers a novel insight into quantitatively analyzing the ion selectivity and paves an alternative way for efficiently salinity gradient energy harvesting via large size nanochannels.

对于盐度梯度能量收集而言，膜离子选择性起着重要作用，在常规研究中通常通过双电层（EDL）重叠度对其进行定性分析。但是，EDL重叠的程度很难定量评估。在这里，我们系统地分析确定能量转换过程的物理向量之间的协同关系，以定量地说明EDL重叠度和离子选择性。提出了三个协同角来描述离子扩散与静电迁移驱动力之间的协同关系。进一步定义了协同度参数，该参数可以提供定量的方式来分析不同浓度比，通道长度和不对称通道几何形状下的阳离子转移数。此外，通过使用纳米线阻滞剂，开发了使用大尺寸纳米通道来有效收集盐度梯度能量的另一种方法。所插入的纳米线阻滞剂可以显着增大协同度参数，从而提高离子选择性，提高膜电位，并显着提高电功率和能量转换效率。这项研究为定量分析离子选择性提供了新颖的见解，并为通过大型纳米通道有效地收集盐度梯度能量铺平了另一种途径。提升了膜的电势，并大大提高了电功率和能量的转换效率。这项研究为定量分析离子选择性提供了新颖的见解，并为通过大型纳米通道有效地收集盐度梯度能量铺平了另一种途径。提升了膜的电势，并大大提高了电功率和能量的转换效率。这项研究为定量分析离子选择性提供了新颖的见解，并为通过大型纳米通道有效地收集盐度梯度能量铺平了另一种途径。