Composite Phase Change Materials with Zn²⁺ Metal–Organic Gel and Carbon Microspheres for Battery Thermal Management

Composite phase change materials (CPCMs) have promising applications as passive cooling technologies in the energy sector. However, the low thermal conductivity and obvious leakage defects of CPCMs limit their large-scale development. Herein, a highly thermally conductive CPCM with polyethylene glycol (PEG), metal–organic gel (MOG), and carbon microspheres (CMS) (PMEC) has been proposed and prepared via a hydrothermal method with noncovalent bonding of metal ions and organic acids. The scanning electron microscopy (SEM) and thermal conductivity of different PMECs indicate that the thermal conductivity of PMEC2 is significantly anisotropic, with 3.79 W·m–1·K–1 when the CMS content is 5 wt %. Besides, the experimental results indicate that PMEC2 can reach a latent heat value of 118 J/g, exhibiting excellent durability after 20 heating and cooling cycles. Additionally, a PMEC2-based battery module incorporating CMS and PEG with epoxy resin (ER) as the supporting skeleton has been assembled for battery modules. The charge and discharge tests are performed on the battery modules at different discharge rates. PMEC2 can control the temperature and temperature difference within 63.03 and 5.01 °C, respectively, which will control the temperature of the battery module and balance the temperature distribution uniformly. This indicates that the designed CPCM can provide an effective approach to explore high thermal conductivity composite materials for thermal management and other energy storage fields.