LiFe₅O₈ (Li_0.5Fe_2.5O₄) nanopowders were synthesized by the sol-gel auto-combustion method and were annealed at different temperatures of 500, 600, 700, and 1100 °C. The spinel phase formation of these samples has been confirmed by X-ray powder diffraction (XRD) technique and Fourier transform infrared (FTIR) spectroscopy. XRD analysis revealed order to disorder phase transition of Li_0.5Fe_2.5O₄ during the annealing temperature. This structural transition was also confirmed by differential scanning calorimetry (DSC). The scanning electronic microscopy images reveal that nanoparticles size increases from 9 nm to 500 nm with increasing annealing temperature. The influence of particle size on elastic parameters has been investigated by FTIR spectroscopy. The band gap energy estimated by UV–vis spectroscopy of LiFe₅O₈ nanoparticles decreased from 1.41 to 1.27 eV when the annealing temperature increases. Furthermore, impedance spectroscopy measurements have been carried out over large frequency and temperature ranges. The conductivity spectrum indicates that the tested specimens are defective. It also shows that the conductivity runs to frequency according to Jonscher’s law. Static conductivity responds to temperature in conformity with a small polaron hopping model whereas dispersive one evaluates according to correlated hopping model. The conductivity gets mixed (electronic and ionic) only when samples were annealed at 700 °C and 1100 °C. According to the Nyquist diagram, each sample is capacitive and resistive. Increasing annealing temperature led to major improvements in permittivity, and a giant low-frequency dielectric constant was observed in the sample annealed at 1100 °C. The total loss (ɛ″) is governed by the conduction mechanism and described by Giuntini's theory. The improved electrical, optical, and elastic properties indicates the potential application LiFe₅O₈ nanoparticles in future multifunctional devices (microelectro-mechanical systems (MEMS), optoelectronic and photovoltaic, photocatalytic activity under visible light, bolometer, low temperature co-fired ceramics (LTCC) and gas sensor applications.).

通过溶胶-凝胶自动燃烧法合成了LiFe ₅ O ₈（Li _0.5 Fe _2.5 O ₄）纳米粉，并在500、600、700和1100°C的不同温度下进行了退火。这些样品的尖晶石相形成已通过X射线粉末衍射（XRD）技术和傅里叶变换红外（FTIR）光谱进行了确认。XRD分析表明Li _0.5 Fe _2.5 O ₄有序向无序相变在退火温度下。通过差示扫描量热法（DSC）也证实了这种结构转变。扫描电子显微镜图像显示，随着退火温度的升高，纳米粒子的尺寸从9 nm增加到500 nm。粒度对弹性参数的影响已通过FTIR光谱进行了研究。LiFe ₅ O _8的紫外可见光谱估计带隙能当退火温度升高时，纳米粒子从1.41降至1.27 eV。此外，已经在较大的频率和温度范围内进行了阻抗谱测量。电导谱表明测试样品有缺陷。它也显示出电导率按照Jonscher定律运行到频率。静态电导率响应温度符合一个小的极化子跳跃模型，而色散则根据相关的跳跃模型进行评估。仅当样品在700°C和1100°C退火时，电导率才混合（电子和离子）。根据奈奎斯特图，每个样本都是电容性和电阻性的。退火温度的升高导致介电常数的大幅度提高，并且在1100℃下退火的样品中观察到巨大的低频介电常数。总损耗（ɛ''）由传导机制控制，并由Giuntini的理论进行描述。改善的电，光和弹性性能表明锂铁的潜在应用未来多功能设备（微机电系统（MEMS），光电和光伏，可见光下的光催化活性，辐射热计，低温共烧陶瓷（LTCC）和气体传感器应用）中的₅ O ₈纳米颗粒。