Nonaqueous rechargeable aluminum batteries

Promises for safe, affordable, environmentally sustainable, and high-performance energy storage technologies have spurred an increased interest in nonaqueous rechargeable Al batteries (RABs) worldwide. However, the complex Al electrochemistry involved in existing nonaqueous RABs has invoked more comprehensive assessments on the implications of overall cell chemistries to the actual battery performance metrics. In this review, we present a summary of reported cathode materials and their corresponding charge storage mechanisms. We critically discuss the implications of overall cell chemistries to the actual battery performance metrics and outline the fundamental and practical limitations of existing RAB chemistries. We also highlight discrepancies in the proposed mechanisms of several RAB systems and further emphasize the importance of an accurate elucidation of the underlying charge storage mechanism involved. We discuss ion migration kinetics in existing electrodes and outline design guidelines for enhancing their performance. Lastly, we provide our perspectives to better understand existing RAB chemistries as they are critically relevant for future research directed at advancing the deployment of nonaqueous RABs.