空心六边形镍钴硫化物/RGO复合物的合成及其超级电容性能

通过两步法制备了一种空心六边形镍钴硫化物(HHNCS)与还原氧化石墨烯(RGO)的纳米复合材料HHNCS/RGO。利用XRD,SEM,TEM和Raman光谱等对复合物进行表征,发现镍钴硫化物为空心六边形结构,并且均匀地附着在RGO的表面。该纳米复合物用作超级电容器电极表现出优异的电化学性能。在电流密度为1 A·g-1时比电容为927 F·g-1;当电流密度增大到20 A·g-1时,比电容仍高达724 F·g-1,表明材料拥有较好的倍率性能。此外,在电流密度5 A·g-1下循环2 000次后比电容保留有初始值的93%,显示出优异的循环稳定性。HHNCS/RGO优异的电容性能主要是由于RGO的存在不仅增强了材料的导电性,而且作为理想的载体分散HHNCS纳米片。HHNCS/RGO纳米复合物优异的电化学性能使其在超级电容器电极材料领域具有应用前景。

Synthesis of Hollow Hexagonal Nickel-Cobalt Sulfide/RGO Nanocomposite for Supercapacitor Application

The uniform nanocomposites of hollow hexagonal nickel-cobalt sulfide/reduced graphene oxide (HHNCS/RGO) are synthesized through a two-step hydrothermal route, and they were characterized by XRD, SEM, TEM and Raman. It is found that nickel-cobalt sulfides with hollow hexagonal structure were uniformly anchored on the surface of RGO sheets. The as-prepared nanocomposites as supercapacitor electrodes present good electrochemical performances. The HHNCS/RGO nanocomposites deliver a maximum specific capacitance of 927 F·g^-1 at the current density of 1 A·g^-1, and still exhibit a high specific capacitance of 724 F·g^-1 at the big current density of 20 A·g^-1, indicating their good rate capability. In addition, the specific capacitance retains 93% of its initial value after 2 000 charge-discharge cycles at the current density of 5 A·g^-1, indicating their high cycling stability. The enhanced capacitive performance is attributed to the fact that RGO can not only improve the conductivity of HHNCS/RGO nanocomposites but also work as support to disperse the HHNCS nanosheets effectively.