Electrolytic Ni-P and Ni-P-Cu Coatings on PCM-Loaded Expanded Graphite for Enhanced Battery Thermal Management with Mechanical Properties.

Abstract

This study addresses the thermal management challenge in battery systems by enhancing phase change material composites with Ni-P and Ni-P-Cu coatings on phase change material/expanded graphite structures. Traditional phase change materials are limited by low thermal conductivity and mechanical stability, which restricts their effectiveness in high-demand applications. Unlike previous studies, this work integrates Ni-P and Ni-P-Cu coatings to significantly improve both the thermal conductivity and mechanical strength of phase change material/expanded graphite composites, filling a crucial gap in battery thermal management solutions. The results reveal that Ni-P-Cu-coated phase change material/expanded graphite composites exhibit a superior thermal conductivity of 27.1 W/m·K, significantly outperforming both uncoated and Ni-P-coated counterparts. Mechanical testing showed that the Ni-P-Cu coating provided the highest compressive strength at 39.4 MPa and enhanced tensile strength due to the coating's highly crystalline structure and smaller grain size. Additionally, the phase-change characteristics of the phase change material/expanded graphite composites, with phase transition temperatures between 38 °C and 43 °C, allowed effective heat absorption, stabilizing battery temperatures under 1.25C and 2.5C discharge rates. Voltage decay analysis indicated that Ni-P and Ni-P-Cu coatings reduced polarization effects, extending operational stability. These findings suggest that Ni-P-Cu-coated phase change material/expanded graphite composites are highly effective in thermal management applications, especially in battery systems where efficient heat dissipation and mechanical durability are critical for performance and safety. This study offers a promising approach to improving energy storage systems for applications such as electric vehicles, grid storage, and portable electronics.