Advanced Thermal Interface Materials: Insights into Low-Temperature Sintering and High Thermal Conductivity of MgO.

Abstract

The escalating frequency of electric vehicle (EV) fires has underscored the critical importance of effective thermal-management in battery package (TMBP). A key challenge in current TMBP lies with the low thermal conductivity (TC, 3 W m^-1 K^-1) of commercial alumina-polymer composite (thermal interface materials, TIM). While magnesia (MgO) TIMs, which show high TC (8-10 W m^-1 K^-1, this study) and low cost, are emerging as an alternative heat-dissipation material (HDM), their full potential remains untapped. Here, the development of novel MgO (≥ 80 W m^-1 K^-1) and MgO TIMs is presented as next-generation HDMs, designed to outperform conventional alumina (20-30 W m^-1 K^-1) and alumina TIMs. Crucially, the fundamental mechanisms enabling our new MgO to achieve an unprecedented TC of ≥ 80 W m^-1 K^-1 are elucidated, significantly surpassing the previously reported range of 40-60 W m^-1 K^-1. This study provides fundamental insights into achieving such high thermal conductivity in MgO. Furthermore, it is demonstrated that this novel MgO TIM cools EV batteries three times faster than commercial alternatives, offering a robust solution for effective EV fire prevention. Consequently, this high-TC MgO is poised to contribute significantly to enhancing EV safety.