Abstract

In this report, efforts were made to investigate and characterize a variety of compositions in a glass system of general formula Na_3+xCr_xTi_2−x(PO₄)₃ (x = 0, 0.25, 0.5 and 0.75 mol%, designated as NCTP_x) to optimize their properties for use in Na-ion batteries. Several crystalline phases such as Na₃Ti₂(PO₄)₃ (COD-4106515) (NASICON), Cr₂O₃ (ICSD-25781) and Cr(PO₃)₃ (ICSD-39410) are precipitated during the process of crystallization. The microstructures of all the glass and glass–ceramic samples are analyzed using SEM and are correlated with powder XRD to explain the ionic conductivity for a given glass–ceramic sample. Single semicircle in the complex impedance plots clearly suggests that the present NCTP_x glass samples exhibit a predominantly single-ion conduction mechanism. Electrical conductivity data follow the Arrhenius equation. The power-law exponent ‘s’ is observed to be the lowest (0.70) for the best conducting glass–ceramic sample NTCP_0.5 (4.24 × 10⁻⁴ S/cm). The electrical modulus study proves that the conductivity relaxation of NCTP_x glass–ceramic samples is temperature independent. Scaling behavior in the normalized spectra indicates that frequency-dependent relaxation behavior is unaffected by the temperature.

Graphic abstract

中文翻译：

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用于Na离子电池的Na 3 + x Cr x Ti 2x（PO 4）3玻璃-陶瓷电解质材料中快速Na离子传导的改进

摘要

在本报告中，我们努力研究和表征了通式为Na _{3+ x} Cr _x Ti _{2- x}（PO ₄）₃（x  = 0、0.25、0.5和0.75 mol％，指定为NCTP _x）以优化其性能，以用于Na-离子电池。几种晶体相，例如Na ₃ Ti ₂（PO ₄）₃（COD-4106515）（NASICON），Cr ₂ O ₃（ICSD-25781）和Cr（PO ₃）₃（ICSD-39410）在结晶过程中沉淀。所有玻璃和玻璃陶瓷样品的微观结构均使用SEM分析，并与粉末XRD相关联，以解释给定玻璃陶瓷样品的离子电导率。复数阻抗图中的单个半圆清楚地表明，当前的NCTP _x玻璃样品显示出主要的单离子传导机制。电导率数据遵循Arrhenius方程。对于导电性最好的玻璃-陶瓷样品NTCP _0.5（4.24×10 ^-4  S / cm），观察到幂律指数s最低（0.70 ）。电模量研究证明NCTP _x的电导率松弛玻璃陶瓷样品与温度无关。归一化光谱中的缩放行为表明，频率相关的弛豫行为不受温度的影响。

图形摘要