Recent advances in passive cooling materials for thermal management in flexible electronics

Flexible electronics has been widely recognized as the future of electronics for a broad range of applications, which is also the foundation for wearable devices that can go on or even seamlessly integrate with the human skin. With the development of device miniaturization, diverse environmental operation and power density enhancement, people have realized the significance of thermal management in flexible electronics. Traditional thermal management methods that rely on active cooling systems often require the use of extensive power and bulk instruments, which consequently restricts the wearability and portability of the devices. Recent breakthroughs in passive cooling materials (PCMs) have offered advanced thermal management solutions for flexible electronics, enabling more opportunities for wearable devices in the fields of medicine, communication, entertainment and many others. This review concentrates on the fundamental principles of PCMs and their recent advances in both materials and devices for flexible electronics. Additionally, we explore potential applications of flexible electronics equipped with passive cooling interfaces in various scenarios, with a special focus on technological feasibility and benefits. We also provide an in-depth discussion on the challenges and prospective solutions for passive thermal management to enhance future cooling techniques.