Hierarchical Thermoelectric Generator (h-TEG)
Radiative-Cooled Wearable Energy Harvesting from Body Heat
Your body continuously dissipates ~100 W of metabolic heat. h-TEG harvests this energy using a hierarchical “couple-chiplet-device” architecture that completely isolates brittle Bi₂Te₃ thermoelectric materials from mechanical strain, enabling both high power output and extreme flexibility.
Read Paper in Nexus
Hierarchical Architecture
Couple
Bi₂Te₃ TE legs
Power generation
Chiplet
Ceramic islands
Strain isolation
Device
Porous Ecoflex + serpentine Ag
Macro compliance
Strain-Isolation Performance
| Condition | Device Strain | TE Internal Strain | Isolation Factor |
|---|---|---|---|
| 10% stretch | 10% | 0.0003% | ~33,000× |
| 30% stretch | 30% | 0.002% | ~15,000× |
| Bending r = 2 cm | 0.7% | 0.00004% | ~17,500× |
| Bi₂Te₃ fracture limit | — | 0.2% | — |
Device Components
Thermoelectric Couples
Bulk Bi₂Te₃ with high-aspect-ratio geometry for maximum thermal gradient capture.
Ceramic Chiplets
Rigid islands that shield TE legs from deformation while acting as heat spreaders.
Serpentine Ag Interconnects
Flexible electrical routing that absorbs macro deformation through buckling and rotation.
Microporous Ecoflex (50% Porosity)
Ultra-soft encapsulation (36.4 kPa) that minimizes weight and thermal shunting.
Cyclic Fatigue Endurance
The h-TEG was subjected to 1,000 continuous cycles combining 70% mechanical stretch with −30% compression. Results demonstrate:
- Zero visible micro-cracking, trace delamination, or macro-scale tearing
- Resistance drift <5% over 1,000 cycles
- Seebeck coefficient drift <5% over 1,000 cycles
- Stable performance from bending radius 0.5 cm to 120% stretch
Publication
Pan, H., Ren, W., Li, X., Jayashankar, D.K., Lu, R., Xu, Q., Fan, F., Duan, M., Tang, H., et al. (2025). “Radiative-cooled hierarchical wearable thermoelectric generator: A nexus of thermal, electrical, and mechanical synergy.” Nexus, 2(4).