Surface Evolution of Aluminum Electrodes in Non-Aqueous Aluminum Batteries

Aluminum batteries are considered as novel devices for safe energy storage. However, there is still a lack of understanding of the operation mechanism and evolution behaviors inside the cells of the current aluminum batteries, which limits the rational design and fabrication of high-performance aluminum batteries. To address the issue, systematical studies were applied to understand the surface evolution of the aluminum electrode in the aluminum batteries. Using in situ optical observation and simulation methods, the results suggest that dendrite growth and deposition on the aluminum electrode surface is critical to the aluminum deposition/corrosion evolution during following cycles, which leads to uneven current distribution on the electrode and inhomogeneous ion concentration interface. Additionally, the activity of the aluminum dendrites suggests that the nanosized aggregation would present less activity than the pristine aluminum, which in turn impacts the uniform evolution of the electrode surface. The aluminum-graphite full cells also exhibit a similar trend that is found in the in situ symmetric cells. The combined results from in situ optical observation, simulation, and full cell evaluation provide a deep insight into the aluminum batteries, which would be meaningful to guide research on their life cycle and evolution.