Insight Into Evaluation of Electrical Properties of Li2MSiO4/Li2M0.5N0.5SiO4 (M, N = Mn, Fe Co, Ni) Cathode Materials

Abstract

A new vision to evaluate rate-capability and electrical properties of the cathode materials of a particular olivine structured family for Li-ion batteries is established. These evaluations obtain electrical conductivity, by noble approaches using DFT, which is related to intrinsic/extrinsic bands concepts and electrical rate-capability. Individual and alloyed transition metals-containing cathodes are investigated, namely, Li₂MSiO₄/Li₂M_0.5N_0.5SiO₄ (M, N = Mn, Fe Co, Ni). Our analysis focused on the electrical properties, including band-gap (BG) and rate-capability, utilizing the GGA(+U)/LSDA(+U) approximations. The electrical properties of the Li₂MSiO₄/Li₂M_0.5N_0.5SiO₄ materials were thoroughly examined by evaluating both the band-gap and electrical rate-capability. For band-gap assessment, we considered two types of band-gap (ILBG/ELBG); while, two criteria (Delta/CCTB) were employed to evaluate the rate-capability. The evaluation of band-gap indicated that all the considered materials exhibited low conductivity. Nonetheless, our findings highlight that the electrical rate-capability of a cell holds greater practical importance than the band-gap property. Our approaches provided reliable predictions for the rate-capability of the alloyed transition metals materials. The theoretically obtained results and conclusions are validated by available experimental data. We conclude that the rate capability approaches are more important than sole band gap. Also, the CCTB approach is more applicable for this electrode family than the Delta. This study can help understanding of behaviors of the alloyed electrode materials. Also, its methodology is worthy to use for other analogous materials.