One‐Pot Fabrication of Layered α‐Phase Nickel–Cobalt Hydroxides as Advanced Electrode Materials for Pseudocapacitors. Issue 1 (2nd October 2014)

• Record Type: Journal Article
• Authors: Chen, Haichao; Jiang, Jianjun; Zhang, Li; Zhao, Yuandong; Guo, Danqing; Ruan, Yunjun; Xia, Dandan
• Is Part Of: ChemPlusChem. Volume 80:Issue 1(2015:Jan.)
• Page Start: 181
• Page End: 187
• Publication Date: 2014-10-02
• Subjects: α phase -- nanostructures -- nickel–cobalt hydroxides -- one‐pot synthesis -- supercapacitors; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201402214
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: A novel and facile one‐step method for growing α ‐phase nickel–cobalt hydroxides is developed. The use of 1‐methyl‐2‐pyrrolidone (NMP) in the mixed solvent plays the decisive role in the precipitation of metal ions and the formation of α ‐phase hydroxides. The synthetic method is robust enough to synthesize Ni–Co hydroxides with different stoichiometric ratios of Ni and Co, and can be extended to the fabrication of Ni0.67 Zn0.33 hydroxide in the α phase. More encouragingly, the method employed can be further used to grow layered nickel‐cobalt hydroxides on Ni foam. As the electroactive materials for pseudocapacitors, the Ni–Co hydroxides deliver an ultrahigh specific capacitance (1337.4 F g −1 at 1 A g −1 for Ni0.67 Co0.33 hydroxide) with improved rate capability and cycling stability. Moreover, a greatly increased specific capacitance (2248.9 and 2286.7 F g −1 at 1 A g −1 for Ni0.5 Co0.5 and Ni0.67 Co0.33 hydroxides, respectively) with superior cycling stability is obtained after growth on Ni foam. Abstract : Nanosheet arrays : Nickel‐cobalt hydroxide nanosheets in the α phase and their arrays on Ni foam are synthesized with the help of 1‐methyl‐2‐pyrrolidone. Their electrochemical properties are tuned by varying the Ni and Co contents. The bimetallic Ni–Co hydroxides exhibit much higher specific capacitances with improved rate capabilities and cycling stabilities compared with monometallic Ni hydroxide (see figure).