With the continuous advancements in electronics towards downsizing and integration, efficient thermal dissipation from chips has emerged as a critical factor affecting their lifespan and operational efficiency. The fan-less chip cooling system has two critical interfaces for thermal transport, which are the contact interface between the base and the chip dominated by thermal conduction, and the surface of the fins dominated by thermal radiation. The different thermal transfer modes of these two critical interfaces pose different requirements for thermal management materials. In the study, a novel approach was proposed by developing graphene thermal transport functional material whose morphology could be intentionally designed via reformed plasma-enhanced chemical vapor deposition (PECVD) methods to meet the diverse requirements of heat transfer properties. Specifically, graphene with multilevel branching structure of vertical graphene (BVG) was fabricated through the hydrogen-assisted PECVD (H₂-PECVD) strategy, which contributed a high emissivity of ~ 0.98. BVG was deposited on the fins’ surface and functioned as the radiation enhanced layer to facilitate the rapid radiation of heat from the heat sinks into the surrounding air. Meanwhile, the well-oriented vertical graphene (OVG) was successfully prepared through the vertical electric field-assisted PECVD process (EF-PECVD), which showed a high directional thermal conductivity of ~ 53.5 W·m⁻¹·K⁻¹. OVG was deposited on the contact interface and functioned as the thermal conduction enhanced layer, allowing for the quick transmission of heat from the chip to the heat sink. Utilizing this design concept, the two critical interfaces in the chip cooling system can be jointly enhanced, resulting in a remarkable cooling efficiency enhancement of ~ 30.7%, demonstrating that this novel material possessed enormous potential for enhancing the performance of cooling systems. Therefore, this research not only provided new design concepts for the cooling system of electronic devices but also opened up new avenues for the application of graphene materials in thermal management.

High-performance electromagnetic interference (EMI) shielding materials with flexibility, excellent mechanical property, and thermal conductivity are highly desired for fifth-generation communications devices. Graphene exhibits tremendous potential due to its high electrical conductivity and unique lamellar structure. However, the construction of densified graphene structure in polymer matrix is still challenging. Herein, we develop a graphene/waterborne polyurethane (G/WPU) flexible film with densified and ordered layer-structure for using as an EMI shielding material. By virtue of the polyvinylpyrrolidone modified strategy and facile liquid phase ball-milling treatment, the graphene nanosheets can be efficiently dispersed into the WPU substrate and tightly connected between each other via internal interactions. Benefiting from the relatively low defects and densified structure of graphene, the resultant G/WPU film yields a high electrical conductivity of 1,004.5 S/m, and a tensile strength of around 48.5 MPa. As a consequence, it achieves an average EMI shielding effectiveness of over 30 dB in the X-band with a thickness of merely 0.15 mm and the value is further enhanced to 73.4 dB at 0.9 mm with a low density of 1.4 g/cm³, offering over 99.99999% shielding of incident electromagnetic waves. More importantly, this G/WPU film also exhibits a high cross-plane thermal conductivity of about 1.13 W/(m·K). Thus, this work develops a high-performance EMI shielding material with both good capacity of heat transmission, but also provides a facile strategy for designing next-generation advanced, lightweight, flexible, and multifunction shielding materials.