Hierarchical CuCo2O4 nanourchin supported by Ni foam with superior electrochemical performance

Abstract

Three-dimensional (3D) hierarchical CuCo2O4 nanourchin architecture assembled from one-dimensional (1D) porous CuCo2O4 nanowire is successfully fabricated on Ni foam using a facile hydrothermal method followed by thermal treatment. The electrochemical properties of the synthesized nanomaterial have further investigated as the binder-free electrode for supercapacitor. Impressively, the porous CuCo2O4 nanourchin electrode exhibits remarkable pseudocapacitive performance with a high specific capacitance of 1569.9 F g-1 at a current density of 0.6 A g−1 (corresponding to 5.2 F cm-2 at 2 mA cm−2), good rate capability and excellent cycling stability (nearly 98.0% capacitance retention after 4000 cycles at a current density of 3.0 A g−1). Moreover, even at a high current density of 20 A g−1, the CuCo2O4 nanourchin electrode still maintains around 71.1% of the initial capacitance over 10000 cycles. The outstanding pseudocapacitive behaviors are mainly due to its hierarchical structure of the porous CuCo2O4 nanourchin architecture which provides large electroactive surface sites, big electrolyte infiltrate area, high-electron/ion-transfer rate and good structure stability. Moreover, an asymmetric supercapacitor based on CuCo2O4 nanourchin on Ni foam as positive electrode and activated carbon (AC) as negative electrode is successfully assembled to further evaluate the electrochemical properties for practical applications. Remarkably, the CuCo2O4//AC asymmetric device has demonstrated a high energy density of 23.9 Wh kg−1 at a power density of 593.2 W kg−1 and excellent cycling stability (91.5% capacitance retention after 2000 cycles).