Construction of multi-structures based on Cu NWs-supported MOF-derived Co oxides for asymmetric pseudocapacitors

Abstract

Cu@MOF core-shell nanowires are synthesized by introducing oxidizable and CTAB-modified metal nanowires as self-engaged templates and supporting MOFs for a one-dimension nanostructure. The following thermal process is controlled to obtain several one-dimension structures of CuCo-mixed materials, such as nanorods, single-shell and double-shell nanowires. The hollow structure for electrode materials enlarges the surface area, provides buffer space for electrolyte to accelerate the ion/charge transfers and for the structure to reduce injuries of volume expansion during cycling. Together with some other merits, such as adequate oxidation of the MOFs, small crystal grains of the material, and well-mixed Cu/Co oxides, the double-shell Cu@MOF nanowires (CuCo-DS5) applied for pseudocapacitors deliver advanced electrochemical performance with a specific capacitance of 563.8 F g−1 at 1 A g−1 as well as an outstanding cycling stability with a 92 % retention after 3000 cycles at 5 A g−1. Meanwhile, an asymmetric pseudocapacitor constructed with the CuCo-DS5 and active carbon (AC) shows a high specific capacitance and energy density.