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• Ultrahigh through-plane thermal conductivity achieved by continuous carbon fibers. • Thermal-induced and slant slicing-induced flexibility. • Leakage proof capacity from polymer skeleton and carbon fiber arrays. • Novel thermal management capacity from high through-plane thermal conductivity and heat absorbed during phase change. With the rapid development of micro-nano electronics, thermally conductive materials with remarkable through-plane thermal conductivity (κ ⊥) and great flexibility are greatly urgent to effective thermal management. The fillers with high thermal conductivity (TC) are commonly assembled to achieve this target. However, the imperfect contact between the joint fillers will lead to high thermal resistance (R), hindering thermal transport. Herein, we fabricated thermal interface materials (TIMs) with ultra-high κ ⊥ (up to 168.4 W m−1 K−1) and adjustable flexibility by the combination of highly thermally conductive carbon fiber bundles (CF) and polymer encapsulated phase change materials (PCMs). The alignment of consecutive CF guarantees the continuity of thermal paths, greatly facilitating thermal transport. While the slantly slicing technique and softening effect of PCMs beyond phase transition temperature lead to an attenuated compression stress (1.6 MPa@10% strain with a CF loading of 50 wt%). What's more, the latent heat absorbed by PCMs is also conducive to thermal management. Thus, during a CPU temperature-control experiment, the application of as-prepared TIMs manifests a temperature decline of 33.9 °C of CPU. This work opens a new perspective to fabricating TIMs with ultrahigh κ ⊥ and low compression stress (σ) by the combination of thermally induced flexible matrix and the slantly slicing technique of aligned CFs. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) are potential candidates in passive thermal regulation and energy storage fields due to their high latent heat capacity around phase transition temperature. However, the leakage problem and low thermal conductivity are two obstructive factors for the extended application of PCMs. Herein, a series of paraffin@silicon dioxide microcapsules (Pa@SiO 2)/graphene sheets (GS)/silicone rubber (SR) phase change composites (PCCs) were prepared. It is found that the inorganic SiO 2 shell is conducive to enhancing the thermal conductivity of PCCs and the double encapsulation by the SiO 2 shell and SR skeleton can restrict the leakage of liquid Pa during phase transition. With a Pa@SiO 2 content of 70 wt%, the PCCs have a high latent heat of 126.1 J/g and enhanced thermal conductivity of 0.37 W m−1 K−1, which is 131.25% higher compared to that of pure SR. In addition, the introduction of graphene sheets further boosts the thermal conductivity of PCCs to 2.69 W m−1 K−1. The obtained PCCs lead to a surprising temperature decline of nearly 35 °C of a commercial lithium-ion battery during a high discharge rate (7.4 C). This work provides an efficient route to fabricate microcapsules-based PCCs for passive thermal regulation. [Display omitted] [ABSTRACT FROM AUTHOR]