Abstract The Li2FeSiO4/C nanomaterial has been prepared by sol-gel method. Systematic studies have been carried out to examine the impact of calcination temperature on structure and its electrochemical properties of Li2FeSiO4/C. The TG/DTA analysis has been used to evaluate the influence of temperature on the pure phase Li2FeSiO4/C nanocomposites. From the Rietveld refined XRD patterns, it is confirmed that the sample calcined at 700 °C and 850 °C possess orthorhombic (Pmn21) and monoclinic (P21/n) structures without any impurity phases. The SEM micrographs indicated the increase of the grain size with increase in the calcination temperature. The results of electrochemical impedance reveal that the orthorhombic Li2FeSiO4/C exhibits higher electronic conductivity of 1.29 × 10−4 Scm−1, which is far better than other samples. The electrochemical behavior of Li2FeSiO4/C in aqueous electrolyte has been studied by cyclic voltammetry (CV). The sample prepared at 700 °C exhibited an excellent electrochemical performance in an aqueous electrolyte, in which almost symmetric CV curves are observed after 50 cycles that indicate good redox reversibility and cycling stability. The Li-ion diffusion coefficient of the sample calcined at 700 °C is 6.24 × 10−12 cm2s−1, revealing a good ionic mobility inside the orthorhombic cage.

中文翻译：

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焙烧温度对锂离子电池Li 2 FeSiO 4 /C纳米正极结构及电化学性能影响的研究

摘要 采用溶胶-凝胶法制备了Li2FeSiO4/C纳米材料。系统研究了煅烧温度对 Li2FeSiO4/C 结构及其电化学性能的影响。TG/DTA 分析已用于评估温度对纯相 Li2FeSiO4/C 纳米复合材料的影响。从 Rietveld 精制的 XRD 图中，证实在 700 °C 和 850 °C 下煅烧的样品具有正交 (Pmn21) 和单斜 (P21/n) 结构，没有任何杂质相。SEM 显微照片表明晶粒尺寸随着煅烧温度的增加而增加。电化学阻抗结果表明，正交晶系 Li2FeSiO4/C 表现出更高的电子电导率，达到 1.29 × 10-4 Scm-1，远优于其他样品。已经通过循环伏安法 (CV) 研究了 Li2FeSiO4/C 在水性电解质中的电化学行为。在 700 °C 制备的样品在水性电解质中表现出优异的电化学性能，其中在 50 次循环后观察到几乎对称的 CV 曲线，表明良好的氧化还原可逆性和循环稳定性。在 700 °C 下煅烧的样品的锂离子扩散系数为 6.24 × 10−12 cm2s−1，表明在正交晶格笼内具有良好的离子迁移率。