▎ 摘　　要

Graphene and graphene-based materials can emit far-infrared light with a wavelength of 6-14 mu m that are beneficial to the human body when subjected low voltage, which have attracted much attention. However, the most previously reported heating devices based on graphene materials are thin films; therefore, there are a series of problems such as poor air permeability, difficulty in integration with clothing, and uncomfortable wearing. In this work, a simple ultrasonic dip-coating method is used to prepare the electric heating yarns based on graphene-coated cotton fibers, where the high-performance hybrid yarns can be driven at a safe voltage. The number of ultrasonic dipcoating and the linear density of the yarns have shown the great influence on electric heating performance. After three ultrasonic dip-coatings, the temperature of the hybrid yarn with 3.5 mm diameter and 10 cm length can reach similar to 70 degrees C at a voltage of 20 V, while the heating power is only similar to 2.5 W. Our studies have demonstrated the potential of hybrid yarns which can be used in the field of heating clothing or medical care.