PEDOT:PSS-Based Stretchable Thermoelectric Fibers with Strain-Enhanced Power Factor

Abstract

The rapid development of miniaturized and wearable electronics has increased the demand for lightweight, highly stretchable, self-powered energy systems compatible with human skin. Thermoelectric (TE) fibers based on conductive polymers have attracted attention for their ability to convert body heat into electricity. However, intrinsically stretchable TE fibers that combine high performance with long-term mechanical durability are still rarely reported. Here, a high-performance stretchable TE fiber was fabricated via a one-step wet-spinning process using Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), Poly(vinyl alcohol) (PVA), and Ti3C2TX (MXene). PVA serves as both an elastic matrix and a template that promotes ordered stacking and improved linearity of PEDOT chains, thereby enhancing charge transport. The resulting composite fiber exhibits a Seebeck coefficient of 31.2 μV K–1, a power factor of 44.0 μW m–1 K–2, and excellent stretchability (>40%). Additionally, a fiber-based TE generator assembled from the composite fibers delivers a power density of approximately 66.4 μW cm–2 at a temperature difference of 40 K. The effects of different MXene loadings on TE and mechanical properties were systematically investigated. This work presents an effective strategy for developing intrinsically stretchable TE fibers, achieving a superior balance between stretchability and electrical performance for wearable energy harvesting and sensing applications.