High-performance compliant thermoelectric generators with magnetically self-assembled soft heat conductors for self-powered wearable electronics

Abstract

Softening of thermoelectric generators facilitates conformal contact with arbitrary-shaped heat sources, which offers an opportunity to realize self-powered wearable applications. However, existing wearable thermoelectric devices inevitably exhibit reduced thermoelectric conversion efficiency due to the parasitic heat loss in high-thermal-impedance polymer substrates and poor thermal contact arising from rigid interconnects. Here, we propose compliant thermoelectric generators with intrinsically stretchable interconnects and soft heat conductors that achieve high thermoelectric performance and unprecedented conformability simultaneously. The silver-nanowire-based soft electrodes interconnect bismuth-telluride-based thermoelectric legs, effectively absorbing strain energy, which allows our thermoelectric generators to conform perfectly to curved surfaces. Metal particles magnetically self-assembled in elastomeric substrates form soft heat conductors that significantly enhance the heat transfer to the thermoelectric legs, thereby maximizing energy conversion efficiency on three-dimensional heat sources. Moreover, automated additive manufacturing paves the way for realizing self-powered wearable applications comprising hundreds of thermoelectric legs with high customizability under ambient conditions.

Linear Electron Beam Assisted Roll-to-Roll in-Vacuum Flexographic Patterning for Flexible Thermoelectric Generators

“…Where electrodes were cleaned (TE:100-15 and TE:100-60), Seebeck per pair is comparable to the reference f-TEG manufactured using the oil free shadow masked electrode (TE:100-ShadowMask), all exhibiting S ~ 0.19 mV K −1 . The power output of these f-TEGs at ΔT = 20 K (conventional operating point near to room temperature for wearable devices) [19] are also similar with P ~ 0.01 nW (TE:100-15 and TE:100-Shadow-Mask) and increased slightly for TE:100-60 to P ~ 0.02 nW. Fluorine is present as Al-F and organic fluorine's associated with a reaction between deposited Al and oil and remaining oil residue, respectively.…”

Recent Progress in the Energy Harvesting Technology—From Self-Powered Sensors to Self-Sustained IoT, and New Applications

“…Human monitoring is undoubtedly another crucial scenario for energy harvesting technology, which is promising evolved as self-powered or self-sustainable wearable/implantable systems for movement monitoring or therapy treatment. Corresponding prototypes can be clothes [226][227][228]; footwear such as socks [152,229], insoles [151,230] and shoes [231,232]; accessories such as glasses [156], wristbands [233,234], gloves [149,215,235], and patches [131,236,237]. Liu et al introduced a hybridized electromagnetic-triboelectric nanogenerator (HETNG) to extract energy and information from the inherent balance control processes, as shown in Figure 6a [238].…”

“…Thus, photovoltaic self-powered gas sensors [123,124], photovoltaic self-powered photodetectors [125,126], self-powered radio-frequency sensors [127,128], photovoltaic self-powered electronic skin [129,130] have been developed by integrating photovoltaic units with related sensors. Thermoelectric self-powered wearable electronics, [131][132][133][134][135], thermoelectric selfpowered electronic skin [136], and thermoelectric self-powered mercury ion sensors [137], pyroelectric self-powered breathing sensors [138,139], and pyroelectric self-powered temperature sensors [140] have been reported by utilizing thermal energy from human body or environment.…”

Thermal Management Systems and Waste Heat Recycling by Thermoelectric Generators—An Overview

“…These features have opened a wide range of applications for TE devices, specifically for low-temperature applications, such as wearable TEGs and thermoelectric cooling systems in medical practices [101]. Self-powered wearable electronics are expected to become more extended and advanced from the wrist and into textiles in people's daily lives [102,103]. Given the immense research and vast commercial prospects in self-powered wearable electronics, new near-term advancements are expected.…”