A novel polyimide composite film with active thermal management capability for battery packaging.

Battery packaging capable of autonomous temperature regulation is a highly attractive strategy for thermal management systems, as it directly enhances safety by mitigating thermal runaway risks. In this work, an integrated battery packaging film capable of simultaneous heat dissipation, low-temperature heating, and real-time temperature monitoring has been successfully developed. By embedding 1D nickel-carbon (1D Ni-C) fibers aligned at a certain angle relative to the film plane together with in-plane oriented 2D graphene (2D GN) to construct a multidimensional heat conduction network, the film achieves maximized thermal conductivity, rapid electrothermal response, and sensitive thermoelectric perception. The obtained film exhibits an exceptional in-plane thermal conductivity of 27.15 W m-1 K-1 (137 times that of pure PI), a high heating efficiency of 136.6 °C cm2 W-1 with only a 3-volt supply voltage that can keep the film temperature stable at 50.1 °C, and a sensitive thermoelectric response (Seebeck coefficient: 12.38 μV °C-1) with a response time of 4 seconds. As a result, this enables rapid, stable Joule heating at low voltages with real-time temperature monitoring, demonstrating effective battery cooling. By integrating dissipation, generation, and sensing in one platform, the film allows for precise thermal management, offering a promising solution for next-generation smart battery systems.