{"title":"Enhancing heat-source free water-floating single-walled carbon nanotube thermoelectric generators with water-absorbing paper","authors":"Yuto Nakazawa, Shuya Ochiai, Yutaro Okano, Reon Okutsu, Yuki Amma, Masayuki Takashiri","doi":"10.1016/j.jpowsour.2025.236966","DOIUrl":null,"url":null,"abstract":"<div><div>Thermoelectric generators (TEGs) are a promising energy-harvesting technology that convert ambient thermal energy into electrical energy. However, their reliance on hot and cold sources to establish a temperature gradient remains a challenge. Water-floating single-walled carbon nanotube (SWCNT) TEGs address this limitation by self-generating a temperature gradient through evaporative cooling in specific areas. Despite this advantage, their temperature gradient is relatively small, leading to a low output voltage. In this study, we embedded water-absorbing paper into SWCNT-TEGs to enhance the temperature gradient and improve performance. Six types of paper with varying water absorbencies were tested, and the performance of the SWCNT-TEGs was evaluated. The output voltage increased with water absorbency, reaching 1.14 ± 0.13 mV–2.3 times higher than a conventional SWCNT-TEG—when placed in 60 °C water without sunlight. This improvement resulted from enhanced evaporative cooling, which increased water vapor generation and amplified the temperature gradient in the SWCNT films. One possible mechanism for enhanced evaporative cooling is enhanced capillary forces at the rough interface between the SWCNT film and the water-absorbing paper, where a thin water film exists. Our findings demonstrate that embedding water-absorbing paper can significantly enhance the performance of water-floating SWCNT-TEGs.</div></div>","PeriodicalId":377,"journal":{"name":"Journal of Power Sources","volume":"642 ","pages":"Article 236966"},"PeriodicalIF":7.9000,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Power Sources","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S037877532500802X","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Thermoelectric generators (TEGs) are a promising energy-harvesting technology that convert ambient thermal energy into electrical energy. However, their reliance on hot and cold sources to establish a temperature gradient remains a challenge. Water-floating single-walled carbon nanotube (SWCNT) TEGs address this limitation by self-generating a temperature gradient through evaporative cooling in specific areas. Despite this advantage, their temperature gradient is relatively small, leading to a low output voltage. In this study, we embedded water-absorbing paper into SWCNT-TEGs to enhance the temperature gradient and improve performance. Six types of paper with varying water absorbencies were tested, and the performance of the SWCNT-TEGs was evaluated. The output voltage increased with water absorbency, reaching 1.14 ± 0.13 mV–2.3 times higher than a conventional SWCNT-TEG—when placed in 60 °C water without sunlight. This improvement resulted from enhanced evaporative cooling, which increased water vapor generation and amplified the temperature gradient in the SWCNT films. One possible mechanism for enhanced evaporative cooling is enhanced capillary forces at the rough interface between the SWCNT film and the water-absorbing paper, where a thin water film exists. Our findings demonstrate that embedding water-absorbing paper can significantly enhance the performance of water-floating SWCNT-TEGs.
期刊介绍:
The Journal of Power Sources is a publication catering to researchers and technologists interested in various aspects of the science, technology, and applications of electrochemical power sources. It covers original research and reviews on primary and secondary batteries, fuel cells, supercapacitors, and photo-electrochemical cells.
Topics considered include the research, development and applications of nanomaterials and novel componentry for these devices. Examples of applications of these electrochemical power sources include:
• Portable electronics
• Electric and Hybrid Electric Vehicles
• Uninterruptible Power Supply (UPS) systems
• Storage of renewable energy
• Satellites and deep space probes
• Boats and ships, drones and aircrafts
• Wearable energy storage systems