Hierarchical MnCo2O4@CuCo2O4 core-shell nanoarrays on carbon cloth as binder-free electrode for flexible all-solid-state asymmetry supercapacitors

Abstract

Hierarchical core-shell nanowire arrays with a shell of CuCo2O4 nanosheets and a core of MnCo2O4 nanowires directly coated on the conductive carbon cloth (CC) are rationally designed and synthesized via a facile hydrothermal route with a post low-temperature thermal treatment in air. The binder-free MnCo2O4@CuCo2O4/CC composite material exhibits an enhanced performance (1241.0 C g−1 at 1 A g−1) compared with the MnCo2O4/CC (832.7 C g−1 at 1 A g−1) and CuCo2O4/CC (734.1 C g−1 at 1 A g−1). In addition, the MnCo2O4@CuCo2O4/CC electrode is assembled into a flexible all-solid-state asymmetric supercapacitor (ASC), which delivers a maximum specific energy of 62.0 Wh kg−1 at a specific power of 747.2 W kg−1 with 91.2% capacity retention after 10000 charge–discharge cycles at 8 A g−1. And the ASC device also exhibits 91.7% capacity retention at floating time over 200 h at 8 A g−1. Further, the MnCo2O4@CuCo2O4//AC device shows superior flexible performance while bending at various angles. These results make this MnCo2O4@CuCo2O4 core/shell composite to be a good candidate for flexible all-solid-state electrochemical capacitors applications.