Along with the technology evolution for dense integration of high-power, high-frequency devices in electronics, the accompanying interfacial heat transfer problem leads to urgent demands for advanced thermal interface materials (TIMs) with both high through-plane thermal conductivity and good compressibility. Most metals have satisfactory thermal conductivity but relatively high compressive modulus, and soft silicones are typically thermal insulators (0.3 W m–1 K–1). Currently, it is a great challenge to develop a soft material with the thermal conductivity up to metal level for TIM application. This study solves this problem by constructing a graphene-based microstructure composed of mainly vertical graphene and a thin cap of horizontal graphene layers on both the top and bottom sides through a mechanical machining process to manipulate the stacked architecture of conventional graphene paper. The resultant graphene monolith has an ultrahigh through-plane thermal conductivity of 143 W m–1 K–1, exceeding that of many metals, and a low compressive modulus of 0.87 MPa, comparable to that of silicones. In the actual TIM performance measurement, the system cooling efficiency with our graphene monolith as TIM is 3 times as high as that of the state-of-the-art commercial TIM, demonstrating the superior ability to solve the interfacial heat transfer issues in electronic systems.

Graphene is usually embedded into polymer matrices for the development of thermally conductive composites, preferably forming an interconnected and anisotropic framework. Currently, the directional self‐assembly of exfoliated graphene sheets is demonstrated to be the most effective way to synthesize anisotropic graphene frameworks. However, achieving a thermal conductivity enhancement (TCE) over 1500% with per 1 vol% graphene content in polymer matrices remains challenging, due to the high junction thermal resistance between the adjacent graphene sheets within the self‐assembled graphene framework. Here, a multiscale structural modulation strategy for obtaining highly ordered structure of graphene framework and simultaneously reducing the junction thermal resistance is demonstrated. The resultant anisotropic framework contributes to the polymer composites with a record‐high thermal conductivity of 56.8–62.4 W m−1 K−1 at the graphene loading of ≈13.3 vol%, giving an ultrahigh TCE per 1 vol% graphene over 2400%. Furthermore, thermal energy management applications of the composites as phase change materials for solar‐thermal energy conversion and as thermal interface materials for electronic device cooling are demonstrated. The finding provides valuable guidance for designing high‐performance thermally conductive composites and raises their possibility for practical use in thermal energy storage and thermal management of electronics.

Random multilayer (RML) structures, or aperiodic superlattices, can localize coherent phonons and therefore exhibit drastically reduced lattice thermal conductivity compared to their superlattice counterparts. The optimization of RML structures is essential for obtaining ultralow thermal conductivity, which is critical for various applications such as thermoelectrics and thermal barrier coatings. A higher degree of disorder in RMLs will lead to stronger phonon localization and, correspondingly, a lower lattice thermal conductivity. In this work, we identified several essential parameters for quantifying the disorder in layer thicknesses of RMLs. We were able to correlate these disorder parameters with thermal conductivity, as confirmed by classical molecular dynamics simulations of conceptual Lennard-Jones RMLs. Moreover, we have shown that these parameters are effective as features for physics-based machine learning models to predict the lattice thermal conductivity of RMLs with improved accuracy and efficiency.

Phase change material (PCM) applied in the glazing structure can decrease building energy consumption and improve indoor thermal comfort by enhancing its thermal energy storage capacity. In the present work, thermal performance of a PCM-filled double glazing unit with different optical properties of phase change material was investigated numerically. The results show that optical properties of PCM play an important role in the thermal performance of double glazing unit filled with PCM, and effect of PCM phase is also strong. Effect of refractive index of PCM on the temperature of double glazing unit is weak, but the effect of extinction coefficient of PCM on the temperature and transmitted energy of double glazing unit is strong. Compared 200m-1 with 5m-1 of extinction coefficient, time to the highest temperature is 30 and 300 minutes earlier in liquid and solid PCM of double glazing unit, and time to the highest transmitted energy is delayed 40 minutes in liquid PCM double glazing unit, but is nearly same in solid PCM double glazing unit.

This article reviews the recent progress towards achieving carbon-based thermoelectric materials. A wide range of experimental and computational studies on carbon allotropes and composites is covered in this review paper. Specifically, we discuss the strategies for engineering graphene, graphene nanoribbon, graphene nanomesh, graphene nanowiggle, carbon nanotube (CNT), fullerene, graphyne, and carbon quantum dot for better thermoelectric performance. Moreover, we discuss the most recent advances in CNT/graphene-polymer composites and the related challenges and solutions. We also highlight the important charge and heat transfer mechanisms in carbon-based materials and state-of-the-art strategies for enhancing thermoelectric performance. Finally, we provide an outlook towards the future of carbon-based thermoelectrics.