Park Chae-Lin, Goh Byeonghwa, Kim Shi Hyeong, Choi Joonmyung
HYU-KITECH Joint Department, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Department of Advanced Textile R&D, Korea Institute of Industrial Technology, 143 Hangaul-ro, Sangnok-gu, Ansan-si 15588, Gyeonggi-do, Republic of Korea.
ACS Appl Mater Interfaces. 2023 Aug 2;15(30):36688-36697. doi: 10.1021/acsami.3c06644. Epub 2023 Jul 10.
Underwater mechanical energy harvesters are of rising interest due to their potential for various applications, such as self-powered ocean energy harvesters, monitoring devices, and wave sensors. Pressure-responsive films and stretch-responsive fibers, which provide high electrical power in electrolytes and have simple structures that do not require packing systems, are promising as harvesters in the ocean environment. One drawback of underwater mechanical energy harvesters is that they are highly dependent on the direction of receiving external forces, which is unfavorable in environments where the direction of the supplied force is constantly changing. Here, we report spherical fleece, consisting of wool fibers and single-walled carbon nanotubes (SWCNTs), which exhibit repetitive electrical currents in all directions. No matter which direction the fleece is deformed, it changes the surface area available for ions to access SWCNTs electrochemically, causing a piezoionic phenomenon. The current per input mechanical stress of the fabricated SWCNT/wool energy harvester is up to 33.476 mA/MPa, which is the highest among underwater mechanical energy harvesters reported to date. In particular, it is suitable for low-frequency (<1 Hz) environments, making it ideal for utilizing natural forces such as wind and waves as harvesting sources. The operating mechanism in the nanoscale region of the proposed fleece harvester has been theoretically elucidated through all-atom molecular dynamics simulations.
水下机械能采集器因其在各种应用中的潜力而越来越受到关注，这些应用包括自供电海洋能量采集器、监测设备和波浪传感器。压力响应膜和拉伸响应纤维在电解质中能提供高电功率，且结构简单，无需封装系统，有望成为海洋环境中的采集器。水下机械能采集器的一个缺点是它们高度依赖于接收外力的方向，这在供应力方向不断变化的环境中是不利的。在此，我们报告了由羊毛纤维和单壁碳纳米管（SWCNT）组成的球形羊毛毡，它在所有方向上都能产生重复电流。无论羊毛毡向哪个方向变形，它都会改变离子通过电化学方式接触SWCNT的可用表面积，从而引发压离子现象。所制备的SWCNT/羊毛能量采集器每输入机械应力产生的电流高达33.476 mA/MPa，这是迄今为止报道的水下机械能采集器中最高的。特别是，它适用于低频（<1 Hz）环境，使其成为利用风、浪等自然力作为采集源的理想选择。通过全原子分子动力学模拟从理论上阐明了所提出的羊毛毡采集器在纳米尺度区域的运行机制。
