石墨烯复合热界面材料以独特优势在高功率密度芯片和航天航空等领域的散热方面应用潜力巨大，但热导率低成为主要制约因素。非平衡声子为开发高性能石墨烯复合热界面材料开辟了新途径而成为国际研究的最前沿热点问题之一，但仍有两个关键难题尚未解决：（1）在复合体系中石墨烯难以发挥自身的高导热性能；（2）不同模式声子界面输运协同优化中的物理机制尚不明确。本项目拟采用双温度模型结合分子模拟的方法，提出定量研究石墨烯内非平衡声子耦合的物理参数，明确非平衡声子耦合强度与石墨烯自身导热性能的内在关系；借助石墨烯表面修饰技术，探究非平衡声子耦合对石墨烯自身导热性能和界面热导的影响规律，采用交流加热－直流探测T形法实验测量进行验证，并利用晶格动力学和声子透射系数揭示非平衡声子耦合对复合体系热导率优化的微观物理机制。本项目力图建立石墨烯复合体系热导率优化的创新机制，为开发新一代高性能石墨烯复合热界面材料提供理论指导。

The thermal interface materials of graphene composites have promising application in the heat dissipation of high power density chips and aerospace due to their excellent merits. However, thermal interface materials of graphene composites are still limited by its low thermal conductivity. The nonequilibrium phonons provides a novel perspective for developing high-performance thermal interface materials and developing high-performance graphene composites based on nonequilibrium phonons is becoming the frontier research and has been attracting intense interest. However, there are still two key problems to resolve: (1) It is difficult to make fully use of the excellent performance of graphene; (2) it is lacking of fundamental understanding of synergistically enhancing the heat conduction of different phonon branches at interfaces. The physical quantity of quantitatively describing the coupling strength of nonequilibrium phonons is proposed to clarify the relationship between the coupling strength of nonequilibrium phonons and the heat conduction performance of graphene using the molecular dynamics simulation combined with two-temperature theoretical model; based on the strategy of graphene surface modification, how the coupling strength of nonequilibrium phonons influences the heat conduction performance of graphene and interfacial thermal conductance is explored, and T type measurement method will be used to verify the simulation results. The lattice dynamics and phonon transmission is utilized to explore the influencing mechanism of nonequilibrium phonons on enhancing thermal conductivity of graphene composites. This project aims to establish the optimization mechanism of enhancing thermal conductivity of composites system based on nonequilibrium phonons and provide theoretical guidance for developing and designing new-generation high-performance graphene composites.