Co-substitution effect on the structural, electrical, and electrochemical properties of nanostructured Co_xNi_1-xMnP₂O₇ (x = 0, 0.25, 0.5, and 0.75)

详细信息    查看全文

• 作者：Salah Kouass ; Amor Fadhalaoui ; Hassouna Dhaouadi ; Fathi Touati
• 关键词：Inorganic compounds ; Impedance spectroscopy ; Electrical properties ; Electrochemical properties
• 刊名：Ionics
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：23
• 期：1
• 页码：55-67
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Electrochemistry; Renewable and Green Energy; Optical and Electronic Materials; Condensed Matter Physics; Energy Storage;
• 出版者：Springer Berlin Heidelberg
• ISSN：1862-0760
• 卷排序：23

文摘

Cobalt-nickel-manganese pyrophosphate nanostructures with formula Co_xNi_1-xMnP₂O₇ were prepared via the hydrothermal method at 150 °C, with further calcinations at 500 °C. A structural analysis of Co_xNi_1-xMnP₂O₇ samples was carried out using X-ray diffraction (XRD). The effect of Co substitution on the structural, electrical, and electrochemical properties of Co_xNi_1-xMnP₂O₇ is reported. The electrochemical results show that the specific capacity increases from 59 to 205 mAh/g with increasing Co content. This study demonstrates the Co substitution effect on the mixed electrical conductivity. The temperature dependence of the dc electrical conductivity, for both pure and Co2+-doped samples, obeys the Arrhenius law. The frequency dependence of ac conductivity for the materials exhibited a Jonscher’s universal power law. The plots of pre-exponent (n) versus temperature suggested that the conduction mechanism can be described using correlated barrier hopping model. The improved electrical conductivity and electrochemical proprieties of Co_xNi_1-xMnP₂O₇ nanomaterials could be ascribed to the synergistic effect of nickel and cobalt ions. The best results have been obtained for the composition x(Co) = 0.75, where the electrical conductivity is maximum, and the Co_0.75Ni_0.25MnP₂O₇ demonstrates the highest specific capacity, implying their promising potential applications in the energy storage.