掺碳铌酸钾纳米片超级电容器电极材料的制备及性能研究

Preparation of Potassium Niobate Nanosheet Composite as Electrode for Supercapacitors

摘要: 高比电容和良好的循环稳定性的高性能新型电极材料对于超级电容器的开发是非常重要的。在本工作中，通过一步法剥离K₄Nb₆O₁₇晶体，我们成功制备了一系列二维大尺寸纳米片。这种尺寸在几个微米左右的超薄纳米片是由双分子层组成的，其厚度约为2 nm。掺碳K₄Nb₆O₁₇作为超级电容器的负极材料表现出优良特性，在电流密度为0.5 A∙g⁻¹时比电容达到330 F∙g⁻¹，同时可适用于大的电流密度(100 A∙g⁻¹，161 F∙g⁻¹)。同时，该材料具有良好的循环稳定性，在电流密度为10 A∙g⁻¹时10,000次充放电之后比电容仅损失5%。这些显著的结果证明了该2D纳米材料在高性能、环保、低成本电化学储能装置领域具有良好的商业潜力。

Abstract: The new electrode materials with large specific capacitance, cycling stability and high capability are important for the development of supercapacitors. In this work, a series of two-dimensional large-size nanosheet was prepared through one-step exfoliating K₄Nb₆O₁₇ crystals. The ultrathin K₄Nb₆O₁₇ nanosheets composed of bilayer sheets were formed with several micrometers in size. Then the K₄Nb₆O₁₇ nanosheets with the thickness of about 2 nm can act as the soft templates of dopamine polymerization. The electrochemical properties of the carbon-doped K₄Nb₆O₁₇ as elec-trode materials for supercapacitor are characterized. More importantly, the results indicated that the C-doped K₄Nb₆O₁₇ exhibit excellent electrochemical performance with high specific capacitances of up to 330 F∙g⁻¹ at 0.5 A∙g⁻¹, durability at high current density (161 F∙g⁻¹ at 100 A∙g⁻¹), and cycling stability (at the current density of 10 A∙g⁻¹, remarkably, delivering over 95% of the initial capacitance after 10 000 cycles). These remarkable results demonstrate the exciting commercial potential for high performance, environmentally friendly and low-cost electrical energy storage and transition devices based on this new 2D nanomaterial.