Modeling the Metal–Insulator Phase Transition in LixCoO2 for Energy and Information Storage

Abstract

AbstractAn electro‐chemomechanical phase‐field model is developed to capture the metal–insulator phase transformation along with the structural and chemical changes that occur in LixCoO2 in the regular operating range of 0.5 < x < 1. Under equilibrium, in the regime of phase coexistence, it is found that transport limitations lead to kinetically arrested states that are not determined by strain‐energy minimization. Further, lithiation profiles are obtained for different discharging rates and the experimentally observed voltage plateau is observed. Finally, a simple model is developed to account for the conductivity changes for a polycrystalline LixCoO2 thin film as it transforms from the metallic phase to the insulating phase and a strategy is outlined for memristor design. The theory can therefore be used for modeling LixCoO2‐electrode batteries as well as low voltage nonvolatile redox transistors for neuromorphic computing architectures.