废旧轮胎原位固相热解高效可控制备碳纳米管研究

The scrapping tyres, also called as “black pollution”, has been causing serious environmental problems, which could be reused as a resource by suitable disposal methods. The pyrolysis technology has been extensively considered as an important route in treating waste tyres, which is in line with the resource, harmlessness, and reduction policies of waste disposal. As one of the important pyrolysis products, the low valuable pyrolytic char (solid byproducts) has restricted the economy and development of the pyrolysis process. Therefore, in this project, solid-pyrolysis technology will be employed to in-situ covert the pyrolytic char into high-valuable carbon nanotubes (CNTs) with high efficiency and excellent controllability, which is expected to significantly increase the value of the pyrolytic solid byproducts. The regulating mechanism on the properties of CNTs will be also presented in this project. In-situ/ex-situ characterizations will be applied to analyze the transformation law and inter-reaction mechanisms among the catalysts, pyrolytic solid byproduct, and pyrolytic gas during the CNTs growth. Molecular-level formation mechanism of CNTs will be unveiled based on the combination the above analysis and first principle calculations. The as-prepared CNTs will be further used as conductive additives for assembling full Li-ion batteries to evaluate its prospect in practical applications, and outline the effects on the slurry, electrochemical properties and the performance of the electrodes. The findings of this project will offer a new strategy for increasing the value of the pyrolytic solid byproducts and enrich the reaction theory of the CNTs formation during in-situ solid pyrolysis. Furthermore, the findings are also important in terms of theoretical development and practical application for pyrolytic reusing scrapping tyres.

废旧轮胎被称为“黑色污染”，严重污染环境，但若采用合理技术可将其资源化。废旧轮胎热解处理是实现废轮胎资源化、减量化和无害化的重要途径，然而低值的热解固相副产物是制约该技术发展的关键因素之一。本项目通过固相热解技术，在废旧轮胎热解过程中，将固相产物原位且高效可控地转化为碳纳米管，实现其高值化利用，并明确碳纳米管性质调控机制。在模拟计算辅助下，借助原位和非原位表征技术，阐明碳纳米管生长过程中催化剂、固相副产物和热解气体组分迁移转化规律和相互作用机制，在分子层面揭示碳纳米管合成机理。将废旧轮胎热解碳纳米管用于锂离子电池导电剂，系统研究其对锂离子电池浆液特性、电极电化学性质和电池性能的影响规律，探明其在锂离子电池领域应用前景。研究成果可丰富对碳纳米管固相合成反应机理的理解，拓展废旧轮胎热解固相副产物高值化利用的科学手段，对废旧轮胎这一类固废资源化利用具有重要的科学和现实意义。

废旧轮胎热解是实现其资源化与无害化处理的主要方法，但传统技术集中在燃料油提取，大量的热解气与热解固相副产物无法消纳，从而造成二次污染和资源浪费。本项目以废旧轮胎为原料，提出热解气与固相副产物高值化利用技术。采用简便的原位热解技术将热解气和固相副产物转化为石墨烯阵列修饰碳材料。系统研究了热解温度、石墨烯阵列生长条件和生物质添加对石墨烯阵列修饰碳材料性质影响规律，揭示了废旧轮胎热解制备石墨烯阵列机理，获得了石墨烯阵列最优生长条件。全面评估了石墨烯阵列修饰碳材料作为负极材料的储钠性能，实验结果表明在电流密度为200 mA g-1下，石墨烯修饰碳负极材料可逆比容量可达350 mA h g-1，在300圈循环后仍可以保持稳定的可逆比容量和库伦效率。储钠机理研究表明，废旧轮胎热解固相碳材料多孔性提供了高的赝电容储钠容量，高导电性石墨烯阵列有效提高了电极材料的倍率和稳定性。此外，本项目设计了连续性废旧轮胎热解制备石墨烯阵列修饰碳材料成套工艺和设备。以上研究成果为废旧轮胎热解固相副产物应用于钠离子电池负极领域的应用奠定理论基础，为废旧轮胎固相副产物高值化回收提供技术支撑。