Zn,Mo共掺杂NiCo2S4电极材料的制备及其超级电容器电化学性能的研究

Preparation of Zn, Mo co-doped NiCo2S4 electrode material and its electrochemical performance for supercapacitors

  • 摘要: NiCo2S4纳米阵列因其优异的导电性和高理论比容量,在超级电容器领域展现出广阔的应用前景。然而,其实际比容量通常远低于理论值,这主要受限于活性位点利用率不足、以及离子/电子传输动力学缓慢等问题。为了解决该问题,本文以碳布(CC)为基底,采用两步水热法成功制备了锌/钼(Zn,Mo)共掺杂的NiCo2S4纳米阵列。在1 mA·cm−2的电流密度下,该电极的面积比电容达到3198.73 mF·cm−2,远高于未掺杂改性的样品。当电流密度增加至20 mA·cm−2时,该电极材料仍具有63.21%的初始电容。进一步将Zn5Mo5-NiCo2S4与活性炭(AC)组装成非对称超级电容器(CC@Zn5Mo5-NiCo2S4//AC),在0.35 A·g−1的电流密度下,该器件的比电容为65.8 F·g−1。在1.75 A·g−1的电流密度下经过5000次循环充放电测试后,该器件仍保持60.37%的初始电容,且库仑效率稳定在96.6%。本研究为开发高性能超级电容器电极材料提供了参考。

     

    Abstract: NiCo2S4 nanoarrays have shown broad application prospects in the field of supercapacitors due to their excellent electrical conductivity and high theoretical specific capacity. However, the actual specific capacity is usually much lower than the theoretical value, which is mainly limited by the insufficient utilization of active sites and the slow kinetics of ion/electron transport. In order to solve this problem, zinc/molybdenum (Zn, Mo) co-doped NiCo2S4 nanoarrays were successfully prepared by two-step hydrothermal method using carbon cloth (CC) as the substrate. At a current density of 1 mA·cm−2, the area specific capacitance of the electrode reaches 3198.73 mF·cm−2, which is much higher than that of undoped modified sample. When the current density is increased to 20 mA·cm−2, the electrode material still has an initial capacitance of 63.21%. Furthermore, an asymmetric supercapacitor (CC@Zn5Mo5-NiCo2S4//AC) was assembled by using Zn5Mo5-NiCo2S4 and activated carbon (AC). The specific capacitance of the device is 65.8 F·g−1 at a current density of 0.35 A·g−1. After 5000 cycles of charge and discharge tests at a current density of 1.75 A·g−1, the device still maintains an initial capacitance of 60.37%, and the coulombic efficiency is stable at 96.6%. This study provides a reference for the development of high-performance supercapacitor electrode materials.

     

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