Low-cost carbon fiber based on eco-friendly precursors is very sought. Although much work focuses on the manufacturing process and mechanical properties improvement of lignin-based carbon fiber, the thermal and electrical properties are seldom investigated. This work reports on systematic investigation about the thermal and electrical properties of lignin/PAN-based carbon fiber mat (CFM). The carbon fiber mat is produced by an industrially available hydrolytic lignin. At room temperature, the thermal conductivity of CFM is determined to be 0.10–0.32 W·m⁻¹·K, indicating that the CFM is a promising candidate for thermal insulation. Furthermore, the structural defect effect on thermal and electrical properties is intensively studied. It is found that the electrical properties of five samples are parallel to each other as temperature is higher than 140 K, which directly indicates the defect effect on electrical transport. For the thermal transport, a new parameter: thermal reffusivity (inverse to thermal diffusivity), is defined which is analogously to the electrical resistivity. The thermal reffusivity theory analyzes the structural defect level quantitatively. The thermal reffusivity theory will guide to tailor the grain size and thermal properties of fabricated materials in the future.

非常寻求基于环保前驱体的低成本碳纤维。尽管很多工作都集中在木质素基碳纤维的制造工艺和机械性能改进上，但很少研究其热学和电学性能。这项工作报告了对木质素/PAN 基碳纤维垫 (CFM) 的热学和电学性能的系统研究。碳纤维垫由工业上可用的水解木质素生产。在室温下，CFM 的热导率确定为 0.10–0.32 W·m ^-1·K，表明CFM 是一种很有前途的隔热材料。此外，还深入研究了结构缺陷对热学和电学性能的影响。发现当温度高于 140 K 时，五个样品的电学性质相互平行，这直接表明缺陷对电输运的影响。对于热传输，定义了一个新参数：热扩散率（与热扩散率相反），它类似于电阻率。热扩散理论定量分析结构缺陷水平。热扩散理论将指导未来定制材料的晶粒尺寸和热性能。