Effect of different aqueous electrolytes on electrochemical behavior of LiFePO4 as a cathode material: Lithium ion battery and renewable energy nexus

Abstract

Lithium iron phosphate as a cathode source is synthesized by a simple hydrothermal synthesis route and its electrochemical performance in different aqueous electrolytes, such as 2M NaOH, 1M Na2SO4, 1M KOH, and 3M KOH is investigated. X-ray diffraction revealed orthorhombic olivine structure with Pbnm (62) space group and lattice parameters a = 4.98 Å, b = 10.04 Å, and c = 5.89 Å. Field emission scanning electron microscopy analysis shows disc form morphology with a particle size distribution in the range of 150 nm -600 nm. In the Raman spectroscopy, the sample's intense peaks at 1390 cm−1 wavenumber indicate the higher ratio of disordered carbon deposit as carbanions material deposited on the LiFePO4 particles.The cyclic voltammetry study confirms the redox reactivity of the LFP cathode and is used to measure the diffusion coefficient of the carrier ion for each electrolyte.Electrochemical impedance spectroscopy is used to predict the chemical kinetics and mass-limitations in the cell.Experimental results showed that the electrochemical efficiency of LiFePO4 can be significantly affected the electrolytes, the maximum peak current, diffusivity, the charge transfer resistance is optimal in case of 1M KOH in comparison to Na2SO4 as well as NaOH.

Keywords

• LiFePO4
• Aqueous electrolytes
• Hydrothermal
• Electrochemical properties
• Lithium-ion batteries