Gao Yang, Mi Liwei, Wei Wutao, Cui Shizhong, Zheng Zhi, Hou Hongwei, Chen Weihua
College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou, Henan 450001, P. R. China.
ACS Appl Mater Interfaces. 2015 Feb 25;7(7):4311-9. doi: 10.1021/am508747m. Epub 2015 Feb 10.
In this paper, the design, synthesis, and measurement of a new and hierarchically structured series of NixCo1-xS1.097 electroactive materials are reported. The materials were synthesized through an ion-exchange process using hierarchically structured CoS1.097 as precursors, and a strategy utilizing the synergistic effect of double metal ions was developed. Two complementary metal ions were used to enhance the performance of electrode materials. The specific capacitance of the electroactive materials was continuously improved by increasing the nickel ion content, and the electric conductivity was also enhanced when the cobalt ion was varied. Experimental results showed that the nickel ion content in NixCo1-xS1.097 could be adjusted from x = 0 to 0.48. Specifically, when x = 0.48, the composite exhibited a remarkable maximum specific capacitance approximately 5 times higher than that of the CoS1.097 precursors at a current density of 0.5 A g(-1). Furthermore, the specific capacitance of Ni0.48Co0.52S1.097 electrodes that were modified with reduced graphene oxide could reach to 1152 and 971 F g(-1) at current densities of 0.5 and 20 A g(-1) and showed remarkably higher electrochemical performance than the unmodified electrodes because of their enhanced electrical conductivity. Thus, the strategy utilizing the synergistic effect of double metal ions is an alternative technique to fabricate high-performance electrode materials for supercapacitors and lithium ion batteries.
本文报道了一系列新型的具有分级结构的NixCo1-xS1.097电活性材料的设计、合成及表征。以具有分级结构的CoS1.097为前驱体，通过离子交换法合成了这些材料，并开发了一种利用双金属离子协同效应的策略。使用两种互补的金属离子来提高电极材料的性能。通过增加镍离子含量，电活性材料的比电容不断提高，同时改变钴离子时电导率也得到增强。实验结果表明，NixCo1-xS1.097中的镍离子含量可在x = 0至0.48范围内调节。具体而言，当x = 0.48时，该复合材料在0.5 A g(-1)的电流密度下表现出显著的最大比电容，约为CoS1.097前驱体的5倍。此外，用还原氧化石墨烯修饰的Ni0.48Co0.52S1.097电极在0.5和20 A g(-1)的电流密度下比电容分别可达1152和971 F g(-1)，且由于其增强的导电性，表现出比未修饰电极更高的电化学性能。因此，利用双金属离子协同效应的策略是制备用于超级电容器和锂离子电池的高性能电极材料的一种替代技术。
