三维微纳分级结构NiO超级电容器电极材料的可控制备

Controllable preparation of three dimensional micro-nano hierarchical structure NiO supercapacitor electrode material

以NiCl_2·6H_2O和NH_3·H_2O为反应原料,赖氨酸为结构调节剂,采用水热-煅烧的方法制备具有微纳分级结构的NiO中空微球材料。通过扫描电子显微镜、透射电子显微镜和X射线衍射等检测方法对NiO材料的微观结构和物相进行分析。结果表明:三维微纳分级结构NiO中空微球由许多NiO纳米片相互堆叠而成,微球大小比较均匀,分散性良好,颗粒粒径约为2~3μm。NiO纳米片边缘清晰,片长约为400~600 nm,厚度仅为40~50 nm。同时,在溶液反应温度为40℃,赖氨酸添加量为0.6 g,水热时间为6 h的条件下,所制备的微纳分级结构NiO微球分散性好,形貌较完整,且具有中空结构。这种独特的结构使得NiO材料具有较高的孔隙率和比表面积,以及相互贯通的孔道,有利于电解质离子和电子的扩散及迁移。将所制备的NiO材料制成工作电极后,采用三电极体系,在1 A/g的电流密度下比电容可达到1 340 F/g,且循环1 000次后,容量保持率为96.5%,显示出优越的电化学性能。

NiO hollow microspheres with micro-nano hierarchical structure were synthesized using lysine as the structure regulator,nickel chloride and ammonia as raw materials through hydrothermal synthesis and calcination method.The microstructure and phase composition of NiO materials were characterized by scanning electronic microscopy(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD)and other detection methods.The results show that the prepared hierarchical NiO hollow microspheres with different sizes are well distributed,and the particle size is about 2-3μm,which is stacked by of many NiO nanosheets.The length of the NiO flakes with clear edges is about 400-600 nm,while the thickness is only about 40-50 nm.Excellent dispersibility and spherical morphology of NiO microspheres can be obtained with addition of 0.6 g lysine at the reaction temperature of 40℃as well as the hydrothermal time of 6 h.In addition,the obtained NiO sphere is hollow,with many flakes stacked and crossed to form a hierarchical structure.Such a unique structure can provide high porosity and specific surface area as well as open channels,all of which are beneficial to the diffusion and migration of both electrolyte ions and electrons.As working electrode,the specific capacitance of the prepared hierarchical NiO hollow microspheres can reach 1 340 F/g in the current density of 1 A/g using the three electrode system and after 1 000 cycles,and the capacity retention rate is 96.5%,showing superior electrochemical performance.