New Materials: Progress In Research On Basalt Fiber Based Thermoelectric Conversion Materials

Thermoelectric materials can directly convert heat energy into electric energy by using the temperature difference at both ends of the element, which has great application potential in waste heat power generation, green refrigeration and other fields. Among a wide range of thermoelectric materials, inorganic fibers have attracted much attention due to their excellent mechanical properties, corrosion resistance and high temperature resistance. Basalt fiber (BF) is a continuous fiber made from natural volcanic rock and melted at high temperature. It has high strength, high temperature resistance and low thermal conductivity, but its insulation characteristics limit its development in the field of thermoelectric fiber.

Recently, the Xinjiang Institute of Physical and Chemical Technology of the Chinese Academy of Sciences and the Chinese University of Hong Kong (Shenzhen) cooperated to disperse one-dimensional carbon nanotubes (CNT) and two-dimensional graphene (RGO) in epoxy emulsion, respectively, and obtained nanocomposite sizing agents with conductive properties. The researchers coated the obtained sizing agent on the surface of basalt fiber to prepare a thermoelectric conversion material based on basalt fiber (Figure 1).

The research shows that the obtained fibers are N-type semiconductors and exhibit excellent thermoelectric conversion performance. The Seebeck coefficient (representing the ability of materials to generate voltage due to temperature difference) is -46.34 µ V/K and - 20.18 µ V/K, respectively µV/K。 Due to the introduction of different nanocomposite sizing agents, the tensile strength of basalt fiber monofilament was increased from 1258MPa (BF) to 1549MPa (CNT/BF) and 1679MPa (RGO/BF), respectively, by 23% (CNT/BF) and 33% (RGO/BF), indicating that the sizing agent has a good repair effect on the surface defect structure of the fiber. In addition, nanocomposite sizing agent can effectively improve the interaction between fiber and resin, and the interfacial shear strength between CNT/BF and RGO/BF and epoxy resin is increased by 52% and 154% respectively. This research endows basalt fiber with unique multifunctional properties through surface modification technology, and provides a new idea for the application of this kind of fiber.

Relevant research results were published in Colloids and Surfaces A: Physicochemical and Engineering Aspects. The research work was supported by the Xinjiang "Tianshan Talents" training program and the Chinese Academy of Sciences.

Preparation and working principle of basalt fiber based thermoelectric conversion material