MODELING SELF-ORGANIZED VOLTAGE OSCILLATIONS IN LI-ION BATTERIES

Amidst the search for next generation Li-ion battery anodes, it was found that Li4Ti5O12 promotes voltage oscillations when the material is calcinated. The process emerges from the complex interaction between phase-separating nanoparticles, as the transition in synchrony in what is known as the group-by-group behavior. In an effort to deepen our understanding on the topic, this work employs numerical simulations to study the voltage oscillations. The simulations were able to reproduce the experimental oscillations, including the effect (dis)charge rate has on oscillation frequency. The formulation of the exchange current model was shown to be critical to oscillation morphology and operation direction asymmetry, an aspect still overlooked in the literature. At last, both surface “wetting” and “dewetting” (accumulation / disaggregation of Li+ on particle surface) has greatly increased oscillation amplitude, reinforcing the major role of surface conditions on the process.