چكيده به لاتين
Lithium-ion batteries (LIB) are widely used in portable electronic device, for instance mobile phone and cameras due to high energy density, high working voltage and long cycle lif. The electrochemical properties of LIBs depend on cathode materials. Among various cathode materials, the spinel structure LiNi0.5Mn1.5O4 (LNMO) with a three dimensional channel for the migration of lithium ions has been considered because of its high energy density (650 Whkg-1) and high working voltage (~ 4.7 vs. Li/Li+).
In this Study, LNMO cathode material synthesized by hydrothermal methode using oxalic acid as precipitant agent followed by high temperature calcination. In this investigation, The effect of hydrothermal temperature, calcination time, concentration of reactants and influence of the citric acid present with different ratios (1,3) have been investigated. Synthesized powder have been characterized by X-ray diffraction, Simultaneous Thermal Analysis, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, Inductively Coupled Plasma mass Spectrometery and electrochemical test.
Synthesized powder using different ratios of citric acid showed the particle size decreased with the ratios of citric acid decreasing (303 to 275nm). Moreover checking of the increase of the reactants concentration revealed an increase in particle growth during the hydrothermal process. According to the results LNMO cathode material synthesized at 140 ℃ after Calcined for 2 hours at 800 ℃ , with a particle size of 513 nm and octahedral shape morpholog have provided discharge capacity 73.14 mAhg-1 at 0.2C rate which has better electrochemical properties than other samples.
