Simultaneous Thermal Management and Voltage Output Enhancement in Rolled Thermoelectric Generators via Coordinated Resistance Tuning and Advanced Heat Spreading

Recent years have witnessed significant advancements in organic thermoelectric material systems, marked by rapidly expanding diversity, which provides a broad material selection platform for organic thermoelectric generators (OTEGs). However, effectively leveraging the intrinsic thermoelectric properties of organic materials through rational material design and device structure optimization remains a central challenge in this field. This work addresses this challenge by employing two easily fabricable organic thermoelectric composite materials: polyaniline/carbon nanotubes doped with camphorsulfonic acid (PANI/CNTs:CSA, p-type) and carbon nanotubes functionalized with polyethylenimine (CNTs:PEI, n-type). These composites were deposited onto flexible cotton fabrics via screen-printing technology and subsequently rolled into a high-thermoelectric-density rolled-type thermoelectric generator (TEG). Under a stable temperature difference (ΔT) of 50 K, the device exhibited favorable thermoelectric conversion performance, achieving an open-circuit voltage of 14.5 mV. Through finite element simulation modeling, this work for the first time established a three-dimensional multiphysics model capable of accurately describing the complex thermoelectric coupling behavior in rolled-type devices, systematically revealing the dynamic coupling mechanism between heat transfer and potential distribution. This approach clarified the intrinsic relationships among the heat source temperature, winding radius, and optimal height required to maximize device output power, thereby establishing universally applicable optimization guidelines. This work provides a theoretical foundation and practical structural optimization strategies for designing rolled-type organic TEG with a higher energy output density, significantly advancing their application in microelectronic self-powered systems.