Urchin-like α-FeOOH@MnO2 core–shell hollow microspheres for high-performance supercapacitor electrode

Abstract

This work details the design and synthesis of novel urchin-like α-FeOOH@MnO2 core–shell hollow microspheres for high-performance electrode materials for supercapacitors. The core–shell heterostructures were constructed by growing strip-like MnO2 nanostructures onto the urchin-like α-FeOOH hollow microspheres that were composed of nanorods. Based on the synergetic effects and multi-functionalities of both the MnO2 shell and urchin-like α-FeOOH hollow cores, the resulting urchin-like α-FeOOH@MnO2 core–shell hollow microspheres exhibited excellent electrochemical performance with a high specific capacitance of 597 F g−1 at 1 A g−1, good rate capability (capacitance retention of 74.2% at 10 A g−1), and remarkable cycling stability (capacitance retention of 97.1% after 2000 cycles). Moreover, an asymmetric supercapacitor fabricated using α-FeOOH@MnO2 as positive electrode and activated carbon as negative electrode was found to deliver a high energy density of 34.2 W h kg−1 and power density of 815 W kg−1. Urchin-like α-FeOOH@MnO2 hollow microspheres demonstrated a high specific capacitance, rate capability and cycling stability, suggesting its promising potential for high-performance supercapacitors.