Rechargeable aluminum metal batteries are ideal for use on a global scale: aluminum is energy dense, earth abundant, low cost, inherently safe, and highly recyclable. However, their technological development has been hindered by fundamental challenges associated with aluminum electrochemistry, coupled with limited molecular-level understanding of how they function and fail. In this talk, I will discuss recent scientific advances from our group in the understanding and design of rechargeable aluminum batteries with a critical eye towards their technological feasibility and potential applications. By coupling electrochemical experiments with solid-state nuclear magnetic resonance (NMR) spectroscopy, new molecular-level understanding of electrochemical reaction mechanisms will be revealed for different positive electrode materials ranging from graphite and organic molecules to transition metal chalcogenides and elemental chalcogenides. Different ion transport regimes will be shown to affect electrochemical reaction pathways, pseudocapacitance, and battery rate performance. New electrolyte mixtures designed using thermodynamic principles will be discussed, including chloroaluminate ionic liquids and their ionic liquid analogues, that result in the improved reversible electrodeposition of aluminum metal from ambient temperatures down to -60 °C. Overall, the results yield new molecular-level understanding aimed at designing rechargeable aluminum batteries for diverse energy storage applications ranging from the electric grid to robotic spacecraft, while yielding critical insights into technological viability and areas of future research.
