Structural, Mechanical, and Dynamical Properties of Amorphous Li₂CO₃ from Molecular Dynamics Simulations

Abstract

Structural, mechanical, and transport properties of amorphous Li2CO3 were studied using molecular dynamics (MD) simulations and a hybrid MD-Monte Carlo (MC) scheme. A many-body polarizable force field (APPLE&P) was employed in all simulations. Dynamic and mechanical properties of Dilithium carbonate, Li2CO3, in amorphous liquid and glassy phases were calculated over a wide temperature range. At higher temperatures, both anion and cation diffusion coefficients showed similar temperature dependence. However, below the glass transition temperature (T < 450 K) the anions formed a glassy matrix, while Li+ continued to be mobile, showing decoupling of cation and anion diffusion. The conductivity of Li+ at room temperature was estimated to be on the order of 10−6 S/cm. Mechanical analysis revealed that at room temperature the amorphous phase had a shear modulus of about 8 GPa, which was high enough to suppress Li metal dendrite growth on an electrode surface.

Keywords

• solid electrolyte interphase
• Li₂CO₃
• Li-ion battery
• molecular simulations