Ti3C2Tx Nanosheets-Modified Phase Change Microcapsules with Thermally Induced Heat Transport Switching for Battery Thermal Management and Thermal Runaway Propagation Mitigation

Abstract Microencapsulated phase change materials for battery thermal regulation require efficient heat transport during normal operation and thermal resistance during thermal runaway propagation. MXene modified inorganic phase change microcapsules (IPCM/MXene) were prepared by inverse emulsion interfacial sol−gel encapsulation using disodium hydrogen phosphate dodecahydrate as the core and SiO2 as the shell. Ti3C2Tx MXene bridged adjacent microcapsules, increasing thermal conductivity by 70.5% while retaining 93.7% of the melting enthalpy of unmodified IPCM. Under high temperature condition, thermal conductivity decreased by 54.6% following MXene oxidation and inorganic residue formation. In 18650 cell tests, IPCM/MXene reduced the peak temperature from 44.7 to 33.7 °C at 3C discharge and maintained stable cooling during repeated cycling. During thermal runaway propagation, the triggering of thermal runaway was delayed by 1899–1970 s, while the interval between the second and third cells increased from 122 to 193 s. These results establish a nonflammable microcapsule design for battery thermal management and safety protection.