Zinc-nickel-cobalt ternary hydroxide nanoarrays for high-performance supercapacitors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (19), p.11826-11835
• Main Authors: Huang, Zi-Hang, Sun, Fang-Fang, Batmunkh, Munkhbayar, Li, Wen-Han, Li, Hui, Sun, Ying, Zhao, Qin, Liu, Xue, Ma, Tian-Yi
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c9ta01995b

The development of high-capacity, stable cycling, and high mass loading cathode materials for asymmetric supercapacitors has been the subject of intense exploration. In this work, a well-aligned zinc-nickel-cobalt ternary (oxy)hydroxide (Zn-Ni-Co TOH) nanostructure with a controlled morphology is used, for the first time, as a high-performance cathode material for supercapacitors. Our findings demonstrate that precursor Zn-Ni-Co TOH materials can deliver superior capacity and rate capability to the Zn-Ni-Co oxide. A high mass loading of 7 mg cm −2 on a carbon cloth substrate is achieved, accompanied by substantially improved facile ionic and electronic transport due to the highly open well-defined nanoarray architecture. The growth mechanism of Zn-Ni-Co TOH was studied in depth by scanning electron microscopy analysis. The optimized Zn-Ni-Co TOH-130 nanowire array electrode delivered an outstanding areal capacitance of 2.14 F cm −2 (or a specific capacitance of 305 F g −1 ) at 3 mA cm −2 and an excellent rate capability. Moreover, the asymmetric supercapacitor assembled with our Zn-Ni-Co TOH-130 cathode exhibited a maximum volumetric energy density of 2.43 mW h cm −3 at a volumetric power density of 6 mW cm −3 and a long-term cycling stability (153% retention after 10 000 cycles), which is superior to the majority of the state-of-the-art supercapacitors. This work paves the way for the construction of high-capacity cathode materials for widespread applications including next-generation wearable energy-storage devices. Zn-Ni-Co ternary hydroxide nanoarrays with a controlled morphology are used as the cathode material for supercapacitors for the first time.