Effect of Alumina Interlayer on the Thermal Conductance at the Cathode-Separator Interface: A Molecular Dynamics Study

Abstract

Efficient thermal management is crucial for improving the performance and reliability of lithium-ion batteries. This study studies the heat transfer at the interface between a LiCoO2 cathode (LCO) and a polyethylene (PE) separator, with an emphasis on the role of an amorphous Al2O3 interlayer. Simulations were performed using the inverse non-equilibrium molecular dynamics (RNEMD) method to investigate the effect of this interlayer on the heat transfer at the interface. In the absence of the interlayer, the sharp temperature drop at the LCO-PE interface indicated a significant thermal resistance in this region. The addition of the Al2O3 interlayer, especially at the LCO-Al2O3 interface, significantly increased the thermal transport. This improvement can be attributed to the strong interfacial adhesion between LCO and Al2O3 in the system. Furthermore, the thickness of the interlayer was identified as a determining factor, and its optimal configuration enabled more efficient heat transfer. Vibrational density of states (VDOS) analysis revealed that Al2O3 acts as an effective phonon bridge, providing significant overlap between the vibrational states of LCO and PE. The findings suggest that amorphous Al2O3 interlayers can significantly reduce the interfacial thermal resistance by providing strong bonding and effective vibrational coupling, and provide a promising solution for optimizing thermal management in high-power lithium-ion batteries.