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We report a facile hydrothermal synthesis method for the large-area growth of self-supported hollow Co3O4 nanowire arrays. The Co3O4 nanowires have an average diameter of 200 nm and grow vertically to the substrates forming aligned nanowire arrays. Interestingly, the as-prepared Co3O4 nanowire arrays combine properties of hollow structure and quasi-single crystallinity. A plausible formation mechanism of hollow Co3O4 nanowire arrays is proposed here. The Co3O4 nanowire arrays grown on the nickel foam are tested as a cathode electrode material for supercapacitor by cyclic voltammograms (CVs) and galvanostatic charge–discharge tests in 1 M KOH. The self-supported hollow Co3O4 nanowire arrays exhibit superior supercapacitor performances with high specific capacitances (599 F g−1 at 2 A g−1 and 439 F g−1 at 40 A g−1) as well as excellent cycle life, making them suitable for high-rate supercapacitor application. The enhanced supercapacitor performances are due to its unique porous structure providing fast ion and electron transfer, large reaction surface area and good strain accommodation.
Xia et al. (Sat,) studied this question.