Inorganic-Organic Synergy Unlocks Stretchable and Self-Healing Thermoelectric Generators with High Output Power

Abstract

Flexible thermoelectric generators (FTEGs) based on polymeric materials can conform to irregular surfaces; however, they often suffer from limited performance and stretchability. To overcome these limitations, we developed an inorganic–organic synergy thermoelectric generator (iosTEG) that delivers superior output power, achieving 2.5 μW under a 40 K temperature gradient in a single-pair configuration, outperforming previous all-organic and hybrid FTEGs. The iosTEG was fabricated via tape-assisted exfoliation of high-crystallinity p- and n-type Bi₂Te₃ flakes, aligned on a flexible, self-healing Ni-bpyPTD polymer. Specifically, the Ni-bpyPTD matrix, synthesized through the crosslinking polymerization of PTD and 4,4′-bis(hydroxymethyl)-2,2′-bipyridine, followed by Ni²⁺ coordination, forms dynamic supramolecular networks that enable stretchability and self-repair via hydrogen bonding and metal–ligand interactions. Moreover, liquid eutectic gallium-indium (EGaIn) was employed as a deformable electrode to bridge the flakes and copper electrode terminals. Notably, the iosTEG retains its functionality upon deformation, maintaining an output voltage of 13.9 mV after stretching (cf. 17.8 mV in the undeformed state, ΔT = 30 K). The iosTEG exhibits excellent mechanical durability, maintaining stable electrical resistance under cyclic deformation, including bending to a 1.0 mm radius and stretchability up to 150%, while autonomously restoring conductivity after damage. The self-healing behavior is further validated by the recovery of R after intentional cutting, highlighting the promise of inorganic–organic integration for stretchable, durable, and high-performance energy devices.