Rose-like ZnNiCo layered double hydroxide grown on Co3O4 nanowire arrays for high energy density flexible supercapacitors

Abstract

Ternary double layer hydroxides are considered as potential electrode materials for high-performance supercapacitors due to their unique layered structure and synergistic effect among their active components. However, the poor stability of these materials during the redox reaction seriously hinders their practical application. Therefore, it is of practical significance to design highly efficient and facile strategy to solve these issues. Herein, rose-like CC@Co3O4/ZNC-LDH hierarchical structure nanowire arrays are successfully synthesized on carbon cloth by a two-step hydrothermal method combined with a calcination process. Due to the unique structural design and the synergistic effect between Zn, Ni and Co elements, the prepared CC@Co3O4/ZNC-LDH nanocomposites exhibit excellent electrochemical properties (2084 mF cm−2 at 1 mA cm−2) and ideal capacitance retention (86.5 % after 10,000 cycles). In addition, the ASC device assembled with CC@Co3O4/ZNC-LDH nanocomposites as the positive electrode and activated carbon as the negative electrode can provide an energy density of 41 Wh kg−1 and a corresponding power density of 958 W kg−1 in a voltage window of 0–1.7 V. A multifunctional display can be lit up for more than 25 min by connecting two ASC devices in series. Therefore, the prepared rose-like CC@Co3O4/ZNC-LDH electrode with hierarchical structure should have a satisfactory practical application prospect.