无定型碳电化学石墨化研究

Artificial graphite, which is prepared through graphitization of amorphous carbon, has many important applications in the field of modern materials and energy. The current graphitization process, the Acheson process invented more than 100 years ago, requires a temperature as high as 3000 centigrade, thus is energy intensive and suffers from great difficulties in failure of equipment materials. Moreover, these high-temperature processes are applicable only to a few “graphitizable” carbons, whereas the majority of amorphous carbons are traditionally “nongraphitizable”. Recently, we found that cathodic polarization in molten calcium chloride can lead to the graphitization of various kinds of amorphous carbons, including that can be derived in large quantities from renewable biomaterials that are traditionally “nongraphitizable”, at merely 820 centigrade. This finding promises a low temperature, low cost process for converting various amorphous carbons to valuable graphite materials. In this project, we will systematically investigate the influence of molten salts, electrode polarization, temperature, and the amorphous carbon type, morphology and size as well as heteroatoms (oxygen, nitrogen and sulfur) doping on the electrochemical graphitization process, and on the composition, structure and morphology of the resulting graphite. We will reveal the mechanism of the electrochemical graphitization, build its physical image. The achievements from this project will lay the foundation for the development of a novel low cost graphitization process, as well as various new graphite based materials.

人造石墨是将无定型碳石墨化的产物，在现代材料、能源等领域有着重要的应用。但现行人造石墨制备仍然沿用一百多年前发明的Acheson工艺，在3000摄氏度高温进行，不仅能耗高，存在设备材料困难，而且仅适用于少数被称为“可石墨化碳”的无定型碳。申请人近期发现可以在氯化钙熔盐(820摄氏度)中通过阴极极化实现各种无定型碳的石墨化，这一发现为实现无定型碳的低温、低成本石墨化提供了新的可能。电化学石墨化适用于多种无定型碳，包括可再生资源碳化碳等传统“不可石墨化碳”。本项目研究将系统研究熔盐组成、极化电势、温度、以及无定型碳种类、形貌尺寸、异原子（氧、氮、硫）掺杂等对无定型碳电化学石墨化过程、产物组成与结构形貌的影响规律。项目研究将揭示电化学石墨化机理，构建其物理图像，为发展一种低成本的无定型碳石墨化新技术及一些新型石墨基材料奠定基础。

人造石墨是将无定型碳石墨化的产物，在现代材料、能源等领域有着重要的应用。但现行人造石墨制备仍然沿用一百多年前发明的Acheson工艺，在3000摄氏度高温进行，不仅能耗高，存在设备材料困难，而且仅适用于少数被称为“可石墨化碳”的无定型碳。本项目基于课题组前期在国际上提出电化学石墨化这一原创思路，系统研究了熔盐电解液组成、极化电势、温度、阴极极化时间等对无定型碳电化学石墨化的影响；深入研究了金刚石、碳微球、淀粉碳电化学石墨化的过程机理；明确了氮、铁等掺杂等对无定型碳电化学石墨化过程、产物组成与结构形貌的影响规律；揭示了电化学石墨化机理。研究表明，电化学石墨化适用于所有非石墨化碳；熔盐体系需具有氧离子溶解能力；极化电势在不大量生成碳化钙的前提下越负越有利于电化学石墨化；石墨化温度不低于750摄氏度；氮掺杂有利于合成高结晶度的石墨；铁可催化石墨纤维的生长。研究成果对电化学石墨化优化工艺的确定具有指导意义，为制备高结晶度的纳米石墨片材料以及石墨纤维材料提供了思路，为发展一种可持续、低成本的人造石墨制备新技术奠定了基础。

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