Ao Chi Kit, Sun Yajuan, Tan Yan Jie Neriah, Jiang Yan, Zhang Zhenxing, Zhang Chengyu, Soh Siowling
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
ACS Cent Sci. 2025 Apr 16;11(5):719-733. doi: 10.1021/acscentsci.4c02110. eCollection 2025 May 28.
Charge separation occurs spontaneously at the solid-liquid interface, forming an electric double layer. Previous methods, including streaming current, used to harvest the constantly separated charge in micron-sized and larger systems reported negligible power output due to the fundamental limit caused by the very short nanoscale Debye length. This study reports on the phenomenon that plug flow of water that falls naturally down a millimeter-sized tube generates electricity with a high efficiency of >10% and power density of ∼100 W/m. This high power breaks the theoretical limit defined by the Debye length in macroscale channels. Plug flow generates 5 orders of magnitude more electricity than continuous flow (i.e., streaming current) and more than other technologies using falling water. Plug flow triggers a unique interfacial chemistry with large chemical potential of charge separation: the complete spatial separation of aqueous H and OH ions without the electric double layer. Having macroscale channels enables the energy of water from nature (e.g., rain or rivers) to be harvested freely. The simple setup lights up multiple LEDs continuously, modifies surfaces, and performs chemical reactions. Plug flow via harvesting energy from nature is a source of renewable power with many advantages for achieving sustainable societies.
电荷分离在固液界面自发发生，形成一个双电层。以前的方法，包括流动电流法，用于在微米级及更大尺寸的系统中收集持续分离的电荷，但由于极短的纳米级德拜长度所导致的基本限制，报告的功率输出可忽略不计。本研究报告了一种现象，即水自然地从毫米级的管子中落下形成的柱塞流能够高效发电，效率大于10%，功率密度约为100 W/m。这种高功率突破了宏观通道中由德拜长度定义的理论极限。柱塞流产生的电力比连续流（即流动电流）多5个数量级，也比其他利用落水的技术产生的电力更多。柱塞流引发了一种具有大电荷分离化学势的独特界面化学现象：水合氢离子和氢氧根离子在没有双电层的情况下实现完全的空间分离。拥有宏观通道能够自由收集来自自然界（如雨水或河流）的水能。这种简单的装置能够持续点亮多个发光二极管、修饰表面并进行化学反应。通过从自然界获取能量的柱塞流是一种可再生能源，对实现可持续社会具有诸多优势。
