In converting a salinity difference to the electrical power by using an ion-selective membrane, achieving a high-power density necessitates both a high ion permeability and ion selectivity of the membrane. However, meeting these two requirements often leads to the conflicting tradeoff in the membrane properties. In this study, we introduce a new mechanistic approach to meeting both requirements by combining an ultra-thin (<100 nm thickness) graphene oxide-based membrane for a high permeability with an asymmetric access area for a high ion selectivity, forming a new type of ionic-diode nanofluidic system. With a graphene oxide/silk fibroin composite membrane, a large power density of is achieved with 32% conversion efficiency under a 1000-fold salt concentration ratio. This approach can be utilized to overcome the low power density limitation with any ultra-thin membranes, and thereby it will provide a new route to utilize blue energy in a reliable and efficient way.

中文翻译：

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基于氧化石墨烯的纳米流体系统利用盐度差发电

在通过使用离子选择性膜将盐度差转化为电能时，实现高功率密度需要膜具有高离子渗透性和离子选择性。然而，满足这两个要求通常会导致膜性能的相互冲突的权衡。在这项研究中，我们引入了一种新的机械方法来满足这两个要求，通过将超薄（<100 nm厚度）氧化石墨烯基膜（用于高渗透性）与不对称访问区域（用于高离子选择性）相结合，形成一种新型膜。离子二极管纳米流体系统。氧化石墨烯/丝素蛋白复合膜在1000倍盐浓度比下实现了32%的高功率密度和32%的转换效率。这种方法可用于克服任何超薄膜的低功率密度限制，从而为可靠、高效地利用蓝色能源提供新途径。