High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics

Flexible thermoelectric generators (FTEGs) harvesting body heat offer a sustainable energy solution for wearables but traditional FTEGs suffer from insufficient power density under natural convection. This study introduces an innovative FTEG with hydrogel-copper foam composite sinks to boost heat di...

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Main Authors: Hejia Wang, Wei Wang, Gang Li, Dessalegn Abera Waktole, Zhengxing Zuo, Boru Jia, Huihua Feng, Mengyu Wang, Shuaiyue shao
Format: Article
Language:English
Published: Elsevier 2025-10-01
Series:Case Studies in Thermal Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214157X25010950
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author Hejia Wang
Wei Wang
Gang Li
Dessalegn Abera Waktole
Zhengxing Zuo
Boru Jia
Huihua Feng
Mengyu Wang
Shuaiyue shao
author_facet Hejia Wang
Wei Wang
Gang Li
Dessalegn Abera Waktole
Zhengxing Zuo
Boru Jia
Huihua Feng
Mengyu Wang
Shuaiyue shao
author_sort Hejia Wang
collection DOAJ
description Flexible thermoelectric generators (FTEGs) harvesting body heat offer a sustainable energy solution for wearables but traditional FTEGs suffer from insufficient power density under natural convection. This study introduces an innovative FTEG with hydrogel-copper foam composite sinks to boost heat dissipation and power output. The hydrogel, embedded in copper foam, leverages the foam's high thermal conductivity and the hydrogel's three-dimensional porous structure to enhance evaporative cooling, while the addition of LiCl enables a long-lasting evaporation–hygroscopic cycle. The FTEG achieves a power density of 167.7 μW/cm2 (2.5 m/s wind speed, ΔT = 20 °C) and 95.4 μW/cm2 under natural convection, 29 × higher than previous results using traditional cooling sinks. The FTEG maintains excellent flexibility, with less than 1 % internal resistance changes after 1000 bending cycles. It successfully powers an electrocardiogram (ECG) sensing system in real-time, generating 83 mV and 840 μW under natural convection using an LTC3108 chip and AD8233 sensor, with 27.98 % power conversion efficiency. The system operates solely on body heat, eliminating the need for batteries or supercapacitors. These results highlight the FTEG's potential for sustainable, efficient wearable electronics.
format Article
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issn 2214-157X
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publishDate 2025-10-01
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series Case Studies in Thermal Engineering
spelling doaj-art-0ce781ebf6154cfd9b6d6f01013c5f302025-08-20T02:58:30ZengElsevierCase Studies in Thermal Engineering2214-157X2025-10-017410683510.1016/j.csite.2025.106835High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronicsHejia Wang0Wei Wang1Gang Li2Dessalegn Abera Waktole3Zhengxing Zuo4Boru Jia5Huihua Feng6Mengyu Wang7Shuaiyue shao8School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaCorresponding author.; School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaSchool of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, ChinaFlexible thermoelectric generators (FTEGs) harvesting body heat offer a sustainable energy solution for wearables but traditional FTEGs suffer from insufficient power density under natural convection. This study introduces an innovative FTEG with hydrogel-copper foam composite sinks to boost heat dissipation and power output. The hydrogel, embedded in copper foam, leverages the foam's high thermal conductivity and the hydrogel's three-dimensional porous structure to enhance evaporative cooling, while the addition of LiCl enables a long-lasting evaporation–hygroscopic cycle. The FTEG achieves a power density of 167.7 μW/cm2 (2.5 m/s wind speed, ΔT = 20 °C) and 95.4 μW/cm2 under natural convection, 29 × higher than previous results using traditional cooling sinks. The FTEG maintains excellent flexibility, with less than 1 % internal resistance changes after 1000 bending cycles. It successfully powers an electrocardiogram (ECG) sensing system in real-time, generating 83 mV and 840 μW under natural convection using an LTC3108 chip and AD8233 sensor, with 27.98 % power conversion efficiency. The system operates solely on body heat, eliminating the need for batteries or supercapacitors. These results highlight the FTEG's potential for sustainable, efficient wearable electronics.http://www.sciencedirect.com/science/article/pii/S2214157X25010950ECG sensorEnergy harvestingFlexible thermoelectric generatorsHydrogel-copper foam
spellingShingle Hejia Wang
Wei Wang
Gang Li
Dessalegn Abera Waktole
Zhengxing Zuo
Boru Jia
Huihua Feng
Mengyu Wang
Shuaiyue shao
High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
Case Studies in Thermal Engineering
ECG sensor
Energy harvesting
Flexible thermoelectric generators
Hydrogel-copper foam
title High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
title_full High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
title_fullStr High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
title_full_unstemmed High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
title_short High-performance flexible thermoelectric generator with hydrogel-copper foam cooling for self-powered wearable electronics
title_sort high performance flexible thermoelectric generator with hydrogel copper foam cooling for self powered wearable electronics
topic ECG sensor
Energy harvesting
Flexible thermoelectric generators
Hydrogel-copper foam
url http://www.sciencedirect.com/science/article/pii/S2214157X25010950
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