Delithiation effects on the structural, electronic, and electrical properties of LiSrFeNiPO material.

In the scope of designing Li-ion batteries with increased energy density, developing new high-performance, stable, and inexpensive cathode materials remains a significant challenge. In this context, the LiSrNiFePO material was synthesized and systematically investigated. Using Density Functional Theory (DFT) calculations, the structural stability and electronic structure were investigated during the delithiation process. The results indicate the stability of the compound during the deintercalation process and revealed a change from semiconducting to semi-metallic behavior. The expected voltage window for this material is between 3.4 and 3.25 V. A comprehensive electrical study was conducted to analyze the conduction mechanism, which is governed by the correlated barrier hopping (CBH) model below 370 K, and the non-overlapping small polaron tunneling (NSPT) model above 370 K. The consistent values of the estimated activation energy related to both conduction and impedance variation prove that the relaxation and conduction processes are governed by the same mechanism.