MnCo2S4/MXene复合材料的制备及其电容性能研究

Preparation and capacitive properties of MnCo2S4/MXene composite

  • 摘要: 过渡金属硫化物(TMSs)因其高理论比容量成为极具吸引力的超级电容器电极材料。然而,其实际电化学性能往往受到导电性不足、离子扩散动力学慢以及循环过程中结构退化等因素的影响,导致活性和稳定性不理想。为解决这些问题,本研究以钴锰乙二醇盐(CoMn-Gly)微球为模板合成新型中空球状MnCo2S4,并与MXene纳米片静电组装成多级MnCo2S4/MXene复合材料。由于特殊的化学成分和微观结构,该复合材料在1 A·g−1时的比容量为287.7 mA·h·g−1(2071.4 F·g−1),在20 A·g−1时的容量保持率为70%。MnCo2S4/MXene//PC(PC表示多孔碳)装置在374.96 W·kg−1时达到81.9 Wh·kg−1的高能量密度。值得注意的是,即使在15 kW·kg−1的超高功率密度下,能量密度仍保持在30.8 Wh·kg−1。此外,该复合材料展现出优异的循环稳定性,在5 A·g−1电流密度下经过10000次循环后仍保持87.2%的初始容量。这些发现凸显了多组分协同(双金属、硫化物与MXene)与分级结构在优化TMSs超级电容器性能中的关键作用,为设计高性能电极材料提供了可行策略。

     

    Abstract: Transition metal sulfides (TMSs) have emerged as attractive electrode materials for supercapacitors due to their high theoretical specific capacity. However, their practical electrochemical performance is often hindered by inadequate electronic conductivity, slow ion diffusion kinetics, and structural degradation during cycling, leading to unsatisfactory activity and stability. To address these challenges, a novel hollow spherical MnCo2S4 was synthesized using CoMn-glycolate (CoMn-Gly) microspheres as templates then electrostatically assembled with MXene nanosheets into a hierarchical MnCo2S4/MXene composite. Owing to the special chemical components and microstructure, the composite exhibits a specific capacity of 287.7 mA·h·g−1 (2071.4 F·g−1) at 1 A·g−1, with 70% capacity retention at 20 A·g−1. The MnCo2S4/MXene//PC (PC means porous carbon) device achieves a high energy density of 81.9 Wh·kg−1 at 374.96 W·kg−1. Notably, even at an ultra-high power density of 15 kW·kg−1, the energy density remains at 30.8 Wh·kg−1. Additionally, the composite exhibits excellent cycling stability, retaining 87.2% of its initial capacity after 10,000 cycles at 5 A·g−1. These findings highlight the critical role of multicomponent synergism (dual metals, sulfur, and MXene) and hierarchical architecture in optimizing TMSs for supercapacitors, providing a viable strategy for designing high-performance electrode materials.

     

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