Utilizing structural batteries in an electric vehicle offers a significant advantage of enhancing energy storage performance at cell- or system-level. If the structural battery serves as the vehicle's structure, the overall weight of the system decreases, resulting in improved energy storage performance (Figure 1B).
Structural batteries exhibit the unique ability to serve as both electrochemical energy storage and structural components capable of bearing mechanical loads with the frameworks or devices they are integrated into.
The lithium-iodine primary battery uses LiI as a solid electrolyte (10−9 S cm −1), resulting in low self-discharge rate and high energy density, and is an important power source for implantable cardiac pacemaker applications. The cathodic I is first reduced into the tri-iodide ion (I3−) and then into the iodide ion (I −) during discharge .
Owing to distinct material subsystems present in electrodes, electrolytes, and separators, the advancements in multifunctionality within structural batteries are explored separately. Striving to concurrently enhance mechanical properties and energy storage performance, several approaches have been reported.
Other lithium-based flow batteries typically use a catholyte based on organometallic complexes, halogen elements or organic redox-active materials with a lithium-metal anode, and most studies have focused on the development of these catholyte materials.
Specifically, multifunctional composites within structural batteries can serve the dual roles of functional composite electrodes for charge storage and structural composites for mechanical load-bearing.