取向石墨烯/铜基复合材料的原位制备与超高导电性能研究

The demands of ultra-high conductive materials with conductivity significantly higher than that of copper and silver in numerous emerging technology areas are increasingly urgent. Metal matrix composites provide a feasible approach for this area, but the difficult points are the coordination of building complex configuration and reinforcement structure integrity, and the formation of excellent electrical contact interface. In view of the above key scientific questions, this project intends to use a powder metallurgy technology of in-situ composite and self-assembly route based on micro-nano flake building units to prepare oriented high-quality graphene-reinforced copper-based laminated composite materials. In order to simplify the study of conductive mechanism, first of all, the micro-scale multilayer thick film prepared by hot pressing of multi-plate CVD graphene/copper foil was used as the model material, and the coupling response mechanism between composite structure/interface and ultra-high conductivity properties is discussed by directional regulation of structural parameters (such as texture and grain size of copper matrix, layer number and quality of graphene, interface structure and topological relation, etc.). On that basis, the similarities and differences of conduction mechanism between the model material and practical material are compared, and the composite configuration and interface of the practical materials are further optimized to construct the preparation technology prototype of ultra-high conductivity graphene/copper matrix composite, providing theoretical basis and practical approaches for the study of conductor materials and the improvement of the transmission efficiency of power and signal and the stability of micro-nano devices in practical application.

众多新兴技术领域对电导率显著高于铜和银的超高导电材料的需求日益迫切。金属基复合材料为该领域提供了一种可行的途径，但难点在于复合构型构建与增强体结构完整性的协同，以及优良电学接触界面的形成。针对以上关键科学问题，本项目拟采用基于微纳片状基元的原位复合和自组装路线的粉末冶金技术，制备取向高质量石墨烯增强的铜基层状复合材料。为简化导电机理研究，首先以多片化学气相沉积石墨烯/铜箔热压制备的微米尺度多层厚膜为模型材料，通过对结构参数（如铜基体织构和晶粒大小、石墨烯层数和质量、界面结构与位相关系等）的定向调控，探讨复合构型/界面与超高导电性能之间的耦合响应机制。在此基础上，比较模型材料与实用材料中超高导电机制的异同，进一步优化实用材料的复合构型和界面，构建超高导电石墨烯/铜基复合材料制备技术原型，为导体材料研究，以及提高实际应用中电力和信号传输效率、微纳器件稳定性等提供理论基础和实用途径。

众多新兴技术领域对电导率显著高于铜和银的超高导电材料的需求日益迫切。石墨烯/金属复合材料是一种极具潜力的超高导电材料，但难点在于复合构型构建与增强体结构完整性的协同，以及优良电学接触界面的形成。针对以上关键科学问题，本项目围绕石墨烯/铜复合构型与界面设计、复合界面调控、超高导电石墨烯/铜复合材料制备与宏量化技术、超高导电机制等主要内容开展了研究，并制备了电导率达到117%IACS的超高导电石墨烯/铜基复合材料。取得了以下主要结论：1、厘清了影响石墨烯/铜超高导电性能的主要因素和机制，其中复合界面原子结构和石墨烯层数与结构完整性对复合界面超高导电性影响显著，寡层高质量石墨烯与金属基体的直接接触是获得超高导电界面和性能的关键；不同复合界面位相关系均有电导增强效应，其中石墨烯(0001)//铜(111)为优化关系。2、实验和第一性原理计算研究表明，金属基体对石墨烯具有强的电子掺杂效应，且复合界面位相关系对电子掺杂浓度大小影响明显，其中石墨烯(0001)//铝(111)与石墨烯(0001)//铝(101)相当，且较石墨烯(0001)//铝(001)高60%以上。而石墨烯/金属复合界面应力大小对电子掺杂效应的影响微弱。3.通过复合构型和形变加工中塑性变形方向的协同设计，建立了超高导电石墨烯/铜复合线材的公斤级宏量化制备技术，且复合线材电导率达到108%IACS以上，为该类新型高性能导体材料的应用奠定了基础。4.基于超高导电复合构型和界面的设计与调控理论，建立了复合基元等离子表面改性的高强高导复合材料制备技术，以及高导热铜基复合材料石墨烯中间层界面调控方法。项目的实施不仅丰富了导体材料的基础理论，而且为多功能金属基复合材料的设计制备提供了指导。此外，所设计制备的超高导电材料及其宏量化技术展现了该类新颖材料良好的应用前景。