Graphene/Polymer Hybrid Fiber with Enhanced Fracture Elongation for Thermoelectric Energy Harvesting

Graphene fibers have gained tremendous attention because of their wide application in wearable energy storage and conversion device. However, it is still a great challenge to achieve a highly conductive graphene-based fiber with acceptable fracture elongation due to the brittle interaction between graphene. Herein, we prepared a graphene and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hybrid fiber with simultaneous enhancement of electrical conductivity and fracture elongation via a hydrothermal process. The optimal electrical conductivity of the hybrid fiber was 96.3 S cm-1, which was about 2 times higher than that of previous reports. Moreover, the fracture elongation doubled to be 10.1% after the introduction of PEDOT:PSS. Furthermore, the dominant charge carriers in the hybrid fibers was altered from the hole to the electron after polyethyleneimine ethoxylated (PEIE) treatment. Finally, a fiber thermoelectric device consisting of three pairs of the as-prepared p- and n-type hybrid fiber was assembled and the output properties were quantified under a serious temperature gradient. This work may provide a good reference to achieve a highly conductive graphene fiber with enhanced fracture elongation for versatile applications.