Electrochemical Performance Optimization of Li2NixFe1−xSiO4 Cathode Materials for Lithium-Ion Batteries

Abstract

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.

Insight into cations substitution on structural and electrochemical properties of nanostructured Li2FeSiO4/C cathodes

“…The diffusion coefficient and the exchange current density of the Li 2 Fe 0.9 Ti 0.1 SiO 4 /C are 1.16 × 10 −12 cm 2 s −1 and 1.42 × 10 −4 mA cm −2 , the (D Li+ ) is comparable with that obtained from CV curves. The particle size forms one of the plausible reason behind the improvement of electrochemical performance since smaller nanoparticles have large surface to volume ratio, and can effectively reduce the grain‐boundary resistance and charge transfer resistance to improve the diffusion coefficient of Li‐ions and high exchange current density in Ti‐doped LFSO/C cathode, which positively influences the specific capacity of the sample.…”