Hydrogel-Based Energy Harvesters and Self-Powered Sensors for Wearable Applications

Abstract

Collecting ambient energy to power various wearable electronics is considered a prospective approach to addressing their energy consumption. Mechanical and thermal energies are abundantly available in the environment and can be efficiently converted into electricity based on different physical effects. Hydrogel-based energy harvesters have turned out to be a promising solution, owing to their unique properties including flexibility and biocompatibility. In this review, we provide a concise overview of the methods and achievements in hydrogel-based energy harvesters, including triboelectric nanogenerators, piezoelectric nanogenerators, and thermoelectric generators, demonstrating their applications in power generation, such as LED lighting and capacitor charging. Furthermore, we specifically focus on their applications in self-powered wearables, such as detecting human motion/respiration states, monitoring joint flexion, promoting wound healing, and recording temperature. In addition, we discuss the progress in the sensing applications of hydrogel-based self-powered electronics by hybridizing multiple energy conversion in the field of wearables. This review analyzes hydrogel-based energy harvesters and their applications in self-powered sensing for wearable devices, with the aim of stimulating ongoing advancements in the field of smart sensors and intelligent electronics.

A 3D-Printed Piezoelectric Microdevice for Human Energy Harvesting for Wearable Biosensors

“…Materials that are used for such piezoelectric nanogenerators (PENGs) are diverse and can include polymers (PVDF, PVDF-TrFE) [16], ceramics (PZT) and materials of biological origin [17,18]. These materials can also be found in a hydrogel form to enhance flexibility and stretchability and to add properties to the material such as self-healing [19]. The energy can be harvested from constant sources such as the cardiovascular and respiratory systems [20,21], but it can also originate from movement, which comes in a form of motion of joints [22] and jogging [23].…”

Recent Progress of Bioinspired Triboelectric Nanogenerators for Electronic Skins and Human–Machine Interaction

“…The development of bionic triboelectric nanogenerators (TENGs) provides innovative opportunities for e-skin and HMI [7][8][9][10][11][12][13]. This innovation is primarily driven by the quest to replicate the complex and nuanced functionalities of natural systems, particularly those of human skin [14][15][16][17][18][19]. Traditional electronic devices often fall short in emulating the dynamic responsiveness and adaptability required for seamless integration with the human body [20][21][22][23][24][25].…”

Recent Progress of Bioinspired Triboelectric Nanogenerators for Electronic Skins and Human-Machine Interaction

“…The development of bionic triboelectric nanogenerators (TENGs) provides innovative opportunities for e-skin and HMI [6][7][8][9][10][11]. This innovation is primarily driven by the quest to replicate the complex and nuanced functionalities of natural systems, particularly those of human skin [12][13][14][15][16][17]. Traditional electronic devices often fall short in emulating the dynamic responsiveness and adaptability required for seamless integration with the human body [18][19][20][21][22][23].…”