Paste-like recyclable Ga liquid metal phase change composites loaded with miscible Ga2O3 particles for transient cooling of portable electronics

• Miscible Ga 2 O 3 particles are introduced into Ga liquid metal to tailor thermophysical properties. • Phase change composites show low supercooling and low thermal interfacial resistance. • Paste-like composites are applied for transient cooling of USB flash disks. • Reusability and recyclability of liquid metal composites are demonstrated. With the increasing power density and continuously added functionalities, normal operation of portable electronic devices such as USB flash disks and smart phones calls for facile and efficient thermal management. Ga-based liquid metals have attracted intensive research attention for thermal management applications because of their high thermal conductivity and low toxicity, but as a type of phase change materials they still suffer from large supercooling and leakage issues. Herein, this work reports direct incorporation of high-loading miscible Ga 2 O 3 particles within Ga liquid metals to prepare non-leakage phase change composites for transient heat absorption. By loading 16.7 wt% of Ga 2 O 3 particles, paste-like liquid metal composites with a high thermal conductivity (∼21 W/m·K), a low interfacial thermal resistance (∼3.5 mm 2 ·K·W −1 ), a small supercooling degree (∼8.8 °C) and a large volumetric latent heat (∼308 J/cm 3 ) were obtained. These advantageous features enable application of the prepared liquid metal phase change composites for high-performance temporary heat absorption of intermittent-use electronic devices such as USB flash disks. Moreover, the attached phase change composites can be easily peeled off from electronic devices, and Ga liquid metals and Ga 2 O 3 particles can be readily recycled by immersing the composites within acidic or basic solutions. The facile direct hand-mixing fabrication process, broadly tailorable supercooling degree and form-stability properties, reusability and recyclability would make the prepared liquid metal composites suitable for phase change-based thermal management applications.