Core-shell structured Fe2O3@Fe3C@C nanochains and Ni–Co carbonate hydroxide hybridized microspheres for high-performance battery-type supercapacitor

Abstract Battery-supercapacitor hybrid (BSH) device is one of the most promising candidates for next advanced energy storage systems because it can bridge the performance gap between lithium ion batteries and conventional capacitors. Herein, we report a novel porous core-shell structured Fe2O3@Fe3C@C nanochains and urchin-like Ni–Co carbonate hydroxide hybridized (denoted as NiCo–CHH) microspheres for advanced battery-type supercapacitors. The as-obtained Fe2O3@Fe3C@C anode shows high specific capacity (611 C g−1) and good rate capability. The fabricated NiCo–CHH cathode delivers high specific capacity (814 C g−1) and excellent cycling stability. When assembled into a battery-type supercapacitor, the NiCo–CHH//Fe2O3@Fe3C@C device delivers a high energy density (95.2 Wh kg−1) and excellent cycling stability. Moreover, In situ Raman spectroscopy proves the reversibility of the NiCo–CHH electrode, and the synergistic effects of Ni and Co ions, further revealing its energy storage mechanism. These findings provide a novel insight on high-performance battery-type supercapacitors.