DOI: https://doi.org/10.55373/mjchem.v27i6.85

Keywords: Cathode material; lithium-ion battery; calcium; doping; LiFePO4

Abstract

This study investigates the effects of calcium (Ca) doping on lithium iron phosphate (LiFePO₄) using the first principles method. Despite its stability and safety, its practical use is limited by low electronic conductivity and sluggish lithium ion diffusion. To address this issue, density functional theory (DFT) simulations were used to investigate how Ca doping influences the mechanical, electrical, and electrochemical properties of LiFePO₄. The results demonstrated that Ca doping reduced the energy gap of LiFePO₄ and FePO4 to 2.164 eV and 1.110 eV, which led to better electron transport and improved electronic conductivity in the cathode material. Additionally, it increased the lithium diffusion coefficient from 1.04 ×10^-11 cm² s^-1 to 1.75 ×10^-10 cm² s^-1, which improved lithium ion mobility and rate capability. There was a slight expansion in lattice parameters which may facilitate better lithium diffusion pathways. Based on its mechanical properties, Ca-doped LiFePO₄ remained stable and there was increased ductility and isotropy which may help prevent microcrack formation during prolonged electrochemical cycling. Overall, the modification enhanced the performance of the LiFePO₄ cathode material, paving the way for advancements in battery technology.