He Yuhui, Huang Zhuo, Chen Bowei, Tsutsui Makusu, Shui Miao Xiang, Taniguchi Masateru
School of Optical and Electronic Information, Huazhong University of Science and Technology, LuoYu Road, Wuhan, 430074, China.
The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.
Sci Rep. 2017 Oct 13;7(1):13156. doi: 10.1038/s41598-017-13336-w.
The Gibbs free energy released during the mixing of river and sea water has been illustrated as a promising source of clean and renewable energy. Reverse electrodialysis (RED) is one major strategy to gain electrical power from this natural salinity, and recently by utilizing nanochannels a novel mode of this approach has shown improved power density and energy converting efficiency. In this work, we carry out an electrokinetic analysis of the work extracted from RED in the nanochannels. First, we outline the exclusion potential effect induced by the inhomogeneous distribution of extra-counterions along the channel axis. This effect is unique in nanochannel RED and how to optimize it for energy harvesting is the central topic of this work. We then discuss two important indexes of performance, which are the output power density and the energy converting efficiency, and their dependence on the nanochannel parameters such as channel material and geometry. In order to yield maximized output electrical power, we propose a device design by stepwise usage of the saline bias, and the lengths of the nanochannels are optimized to achieve the best trade-off between the input thermal power and the energy converting efficiency.
河水与海水混合过程中释放的吉布斯自由能已被证明是一种有前景的清洁可再生能源来源。反向电渗析（RED）是从这种自然盐度获取电能的一种主要策略，最近通过利用纳米通道，这种方法的一种新模式已显示出提高的功率密度和能量转换效率。在这项工作中，我们对从纳米通道中的RED提取的功进行了电动分析。首先，我们概述了沿通道轴额外反离子不均匀分布引起的排斥电位效应。这种效应在纳米通道RED中是独特的，如何针对能量收集对其进行优化是这项工作的核心主题。然后我们讨论了两个重要的性能指标，即输出功率密度和能量转换效率，以及它们对纳米通道参数（如通道材料和几何形状）的依赖性。为了产生最大化的输出电功率，我们提出了一种通过逐步使用盐度偏置的器件设计，并对纳米通道的长度进行了优化，以在输入热功率和能量转换效率之间实现最佳权衡。
