Mammal-Skin-Inspired Adaptive Nanocomposites Cooling Membrane for Passive Battery Thermal Management

Efficient and flame-retardant thermal management of lithium-ion batteries (LIBs) is drawing increasing attention. Herein, we report a mammal-skin-inspired self-adaptive hygroscopic nanocomposite cooling membrane that dissipates heat from LIBs via moisture desorption and subsequently recovers its cooling capacity through spontaneous moisture absorption from ambient air. The multifunctional cooling membrane, comprising hygroscopic salt, graphene oxide, active carbon fiber, an anticorrosion copper frame, and a porous membrane, is fabricated and systematically characterized, exhibiting both outstanding cooling performance and excellent flame retardancy. Proof-of-concept experiments demonstrate that the self-adaptive cooling membrane is able to achieve an average cooling power of 802.5 W m^-2 with a temperature reduction of 34.3 °C at a heat flux of 2.7 kW m^-2, indicating a substantial improvement over existing passive cooling strategies with a low cost. When applied to a real 3.7 V/12 Ah LIB at a cyclic discharging-charging rate of 4C, this strategy extends the tested LIB lifetime from 118 to 233 cycles, enabling an additional total capacity of 1445.9 Ah. Long-term cycling tests at 3C reveal that the LiCl/GO@ACF membrane still maintains desirable thermal management performance after 1000 h, without risks of leakage or corrosion. Meanwhile, this cooling strategy shows superior flame retardancy and thermal stability, demonstrating the ability to inhibit thermal runaway. The flame-retardant cooling membrane developed in this study shows strong potential for enabling high-efficiency and cost-effective passive battery thermal management.