High-performance solid-state supercapacitors integrated with thermal management systems based on phase change materials: All in one

Electrochemical energy storage (EES) devices such as batteries and supercapacitors (SCs) have been widely used in electric vehicles and portable electronics. However, safety issues and performance degradation of these devices, particularly when working at elevated temperatures, limit their further applications. Here, we propose a new all-in-one design of high-performance solid-state SCs integrated with thermal management systems by developing a multifunctional solid-state polymer electrolyte (SPE) with encapsulated phase change materials (PCMs). The PCM-containing SPEs exhibited a homogenously dispersed core-shell-like structure. The paraffin wax (PW) core a typical organic PCM could store a large amount of thermal energy upon phase transitions. The shell, polyvinyl alcohol (PVA)/H2SO4 frameworks, could provide interconnected ion-conducting pathways, keep the encapsulated PW in the form of micro-sized particles and prevent it from leaking during the melting, and serve as separators. Consequently, the temperature rise of the all-in-one, solid-state SCs integrated with PCMs can be effectively suppressed under thermal abuse conditions. Moreover, the all-in-one devices can retain high capacitance, outstanding rate capability, and excellent stability upon charge/discharge and heating/cooling cycles. Therefore, the rationally designed multifunctional SPEs may open a new pathway to design novel highperformance and safe all-in-one devices with integrated EES and thermal management systems.