In the context of 5G, the high-frequency cyclicity and inhomogeneity of heat flow put forward higher requirements for the thermal control system of electronic devices, and there is a great need for thermal management modules with fixed point and high efficiency to ensure the long-term development of electronic devices. Here, we selected four phase change molecules with significant differences in phase change temperatures to be composited with graphene aerogel (GA) to obtain Ei@GA, Tetra@GA, Octa@GA, and 1,10-Deca@GA. Compared with pure phase change molecules, the thermal conductivity has been increased by more than 20%, and the relative enthalpic efficiency is as high as 98.7% or more. Further, we assembled the four phase change composites by “reduction welding” to obtain the integrated, modular thermal management device M₁-PCMs@GA. Simulation of inhomogeneous heat generation in electronics by building an inhomogeneous heat generation platform. Compared with the homogeneous modules M₂-Ei@GA and M₃-1,10-Deca@GA, the effective temperature control time of the customized module M₁-PCMs@GA is extended by 100.0 and 394.3 s, respectively. Therefore, custom-assembled modular thermal management devices have important application prospects in the field of intelligent temperature control of electronic devices, and the idea of cascade assembly enriches the application functions and development direction of intelligent thermal managers.

With the rapid development of science and technology, electronic devices are moving towards miniaturization and integration, which brings high heat dissipation requirements. During the heat dissipation process of a heating element, heat may spread to adjacent components, causing a decrease in the performance of the element. To avoid this situation, the ability to directionally transfer heat energy is urgently needed. Therefore, thermal interface materials (TIMs) with directional high thermal conductivity are more critical in thermal management system of electronic devices. For decades, many efforts have been devoted to the design and fabrication of TIMs with high-directional thermal conductivity. Benefiting from the advantage in feasibility, low-cost and scalability, compositing with thermal conductive fillers has been proved to be promising strategy for fabricating the high-directional thermal conductive TIMs. This review summarizes the present preparation technologies of polymer composites with high-directional thermal conductivity based on structural engineering of thermal conductive fillers, focusing on the manufacturing process, mechanisms, achievements, advantages and disadvantages of different technologies. Finally, we summarize the existing problems and potential challenges in the field of directional high thermal conductivity composites.

The proliferation of high-power, highly informationized, and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic (EM) pollution and thermal accumulation. These issues, in turn, impose constraints on the performance of such equipment and jeopardize personnel safety. Carbon materials, owing to their diverse and modifiable structures, offer adjustable thermal and electric conductivity, rendering them highly promising for applications in fields such as thermal management and EM protection which have garnered extensive research and review. The pursuit of integrated device and equipment development has elevated the demand for multifunctional materials, prompting significant research into carbon-based composite materials that include both thermal management and EM protection functionalities. Notably, there are no relevant reviews on this topic at present. Consequently, this work consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM protection. These attributes include thermally conductive electromagnetic interference (EMI) shielding materials, thermally insulating EMI shielding materials, thermally conductive EM wave (EMW) absorbing materials, and thermally insulating EMW absorbing materials. The paper elucidates the fundamental principles underpinning thermal conduction, thermal insulation, EMW absorbing, and EMI shielding. Additionally, it engages in discussions surrounding areas of contention, design strategies, and the functional properties of various material designs. Ultimately, the paper concludes by presenting the challenges encountered and potential research strategies about composites endowed with both thermal management and EM protection functionalities, while also envisaging the development of novel multifunctional EM protection materials.

Photoisomerization-induced phase change are important for co-harvesting the latent heat and isomerization energy of azobenzene molecules. Chemically optimizing heat output and energy delivery at alternating temperatures are challenging because of the differences in crystallizability and isomerization. This article reports two series of asymmetrically alkyl-grafted azobenzene (Azo-g), with and without a methyl group, that have an optically triggered phase change. Three exothermic modes were designed to utilize crystallization enthalpy (∆H_c) and photothermal (isomerization) energy (∆H_p) at different temperatures determined by the crystallization. Azo-g has high heat output (275–303 J g⁻¹) by synchronously releasing ∆H_c and ∆H_p over a wide temperature range (−79 °C to 25 °C). We fabricated a new distributed energy utilization and delivery system to realize a temperature increase of 6.6 °C at a temperature of −8 °C. The findings offer insight into selective utilization of latent heat and isomerization energy by molecular optimization of crystallization and isomerization processes.

Layered double hydroxides (LDHs) are widely used owing to their unique alternating anionic and cationic layered two-dimensional (2D) structures. However, studies on the preparation of 2D LDH nanosheets with uniform thickness and their photodetectors are limited. In this study, two novel ultrathin LDH (Ca-In and Ca-Al LDH) nanosheets are peeled off from precursor bimetallic phosphides through the original precursor method. Both Ca-In and Ca-Al LDH nanosheets demonstrate a uniform thickness distribution with an average thickness of 3–4 nm, micron-level lateral sizes, and moderate bandgap. Owing to its broad light absorption range, hydrophilicity, and stability, Ca-In and Ca-Al LDH nanosheets are applied for the first time in photoelectrochemical photodetectors, realizing a wide range of light detection from ultraviolet (365 nm) to visible light (635 nm). Moreover, the fabricated photodetectors exhibit excellent cycle stability, and the average photocurrent density shows no reduction after 70 days. Therefore, this study provides an effective method to prepare 2D Ca-In and Ca-Al LDH nanosheets with uniform thickness and photoelectric application prospects.

The enhancement of the fluorination degree of carbon fluorides (CF_x) compounds is the most effective method to improve the energy densities of Li/CF_x batteries because the specific capacity of CF_x is proportional to the molar ratio of F to C atoms (F/C). In this study, B-doped graphene (BG) is prepared by using boric acid as the doping source and then the prepared BG is utilized as the starting material for the preparation of CF_x. The B-doping enhances the F/C ratio of CF_x without hindering the electrochemical activity of the C–F bond. During the fluorination process, B-containing functional groups are removed from the graphene lattice. This facilitates the formation of a defect-rich graphene matrix, which not only enhances the F/C ratio due to abundant perfluorinated groups at the defective edges but also serves as the active site for extra Li⁺ storage. The prepared CF_x exhibits the maximum specific capacity of 1204 mAh g⁻¹, which is 39.2% higher than that of CF_x obtained directly from graphene oxide (without B-doping). An unprecedented energy density of 2974 Wh kg⁻¹ is achieved for the as-prepared CF_x samples, which is significantly higher than the theoretically calculated energy density of commercially available fluorinated graphite (2180 Wh kg⁻¹). Therefore, this study demonstrates a great potential of B-doping to realize the ultrahigh energy density of CF_x cathodes for practical applications.

Optimizing the structure of electrode materials is one of the most effective strategies for designing high-power microbial fuel cells (MFCs). However, electrode materials currently suffer from a series of shortcomings that limit the output of MFCs, such as high intrinsic resistance, poor electrolyte wettability, and low microbial load capacity. Here, a three-dimensional (3D) nitrogen-doped multiwalled carbon nanotube/graphene (N-MWCNT/GA) composite aerogel is synthesized as the anode for MFCs. Comparing nitrogen-doped GA, MWCNT/GA, and N-MWCNT/GA, the macroporous hydrophilic N-MWCNT/GA electrode with an average pore size of 4.24 µm enables high-density loading of the microbes and facilitates extracellular electron transfer with low intrinsic resistance. Consequently, the hydrophilic surface of N-MWCNT can generate high charge mobility, enabling a high-power output performance of the MFC. In consequence, the MFC system based on N-MWCNT/GA anode exhibits a peak power density and output voltage of 2977.8 mW m⁻² and 0.654 V, which are 1.83 times and 16.3% higher than those obtained with MWCNT/GA, respectively. These results demonstrate that 3D N-MWCNT/GA anodes can be developed for high-power MFCs in different environments by optimizing their chemical and microstructures.