Electrochemistry

This study employs a novel electrochemical method to mimic the cyclic redox reactions occurring over long geological timescales in accelerated manner. The results revealed that the kinetics and electron flux of the cyclic redox reaction are key to the layer-to-tunnel structure transformation of Mn oxides, provided new insights for natural biotic and abiotic redox reactions and explained the dominance of todorokite in nature.

Because a Li metal battery stores at least ten times more electricity than a Li-ion battery, it is promising a next generation rechargeable battery system. However, during routine charging and discharging cycles, Li dendrites grow on the Li metal electrode, degrade the battery’s performance, and even cause short-circuits. Using transmission mode grazing incidence small angle X-ray scattering, I found that an increase of current density resulted in a smaller radius for Li primary particles, e.g., 5.4 nm at 0.1 mA/cm², 4.5 nm at 0.5 mA/cm², and 3.5 nm at 2.0 mA/cm². I also demonstrated the fractal-similarity of Li dendrites in nanoscale to microscale observations. Our nanoscale observations, which have not been reported, could shed light on diverse nanoengineering routes to control the interface at the Li metal anode and solve the Li dendrite formation problem.