Three-dimensional interconnected MnCo2O4 nanosheets@MnMoO4 nanosheets core-shell nanoarrays on Ni foam for high-performance supercapacitors

Abstract

Rational design and fabrication of core-shell nanoarrays (CSNs) with distinctive architectures and desirable capacitive performances are believed to be a promising and challenging strategy toward advanced electrode materials for supercapacitors (SCs). In this work, we report a two-step synthesis of three-dimensional (3D) MnCo2O4 nanosheets@MnMoO4 nanosheets CSNs on Ni foam (NF), which are constructed by vertically growing MnMoO4 nanosheets onto interconnected MnCo2O4 nanosheets arrays (NAs). Such MnCo2O4@MnMoO4 CSNs can make full use of its unique 3D architecture and the synergistic effect between MnCo2O4 and MnMoO4. Therefore, the prepared MnCo2O4@MnMoO4 CSNs, as a binder-free electrode for SCs, demonstrate a significantly enhanced specific capacity (885 C g−1 at 3 A g−1), higher rate capability (629 C g−1 at 30 A g−1), and better cycling stability (95% capacitance retention after 5000 cycles at 10 A g−1) compared with the single MnCo2O4 or MnMoO4 NAs electrode. Moreover, the assembled asymmetric SC cell (ASC) based on MnCo2O4@MnMoO4//activated carbon (AC) also exhibits a specific capacity (222 C g−1 at 1 A g−1) and an energy density (49.4 W h kg−1 at 815 W kg−1), indicating a promising practical application for the prepared MnCo2O4@MnMoO4 CSNs in high-performance SCs.