Integrated bilayer phase change composite polyimide aerogel with the dual-mode thermal management of passive insulation and active dissipation

Increasing power density in electronics renders thermal management critical. However, traditional materials with singular thermal functions fail to withstand complex thermal environments, while existing multi-layered composites often suffer from weak interfacial adhesion and leakage of liquid phase change material (PCM). To address the challenges, a bilayer phase change composite polyimide (PI) aerogel featuring orthogonal pore channels is constructed via directional freezing. It integrates a PI insulation layer with an ultralow thermal conductivity of 0.032 W m −1  K −1 and a polyethylene glycol (PEG)-loaded graphene oxide (GO)/PI dissipation layer with a latent heat of 174.9 J g −1 . To ensure strong interfacial performance, a co-imidization strategy using chemically homologous precursors is employed to create a dense and interlocked interface, which achieves a tensile strength of 20.8 MPa and effectively prevents liquid PEG leakage. As for the modulated thermal management of batteries, the surface temperature of the modulated battery achieves a maximum reduction of 38 °C under normal working conditions, while the adjacent battery remains below 50 °C for 2.5 h under the extreme condition of thermal runaway at 200 °C. The bilayer phase change composite aerogel demonstrates great potential for practical applications, especially for high-power batteries and electronic equipment.