Enhance the performance of iron oxide nanoparticles in supercapacitor applications through internal contact of α-Fe2O3@CeO2 core-shell

Abstract

The α-Fe2O3@CeO2 core-shell heterostructure was used as an advanced material for electrodes in supercapacitors. Due to the close contact between α-Fe2O3 core nanoparticles and CeO2 shells, the obtained electrochemical results could function in an excellent manner. The core-shell structured α-Fe2O3@CeO2 sample demonstrated lower band gap energy (2.1 eV) in comparison to the pure α-Fe2O3 (2.23 eV) and CeO2 (2.85 eV) samples, leading to the perfect electrochemical and capacitance activity. They also had a specific capacitance of 168 F g−1 at 5 mV s−1 and the capacity of the tested core-shell electrode proved to be double as high as that of α-Fe2O3 and 7 times of CeO2 electrodes. Asymmetric supercapacitor made of reduced graphene oxide (RGO) and α-Fe2O3@CeO2 core-shell increased the potential window by up to 1.5 V in an aqueous electrolyte and exhibited a energy density of 15.6 W h kg−1. The devise had acceptable cycling ability after 2000 cycles. As much as 87.5% of the initial specific capacitance remained. Improved electrochemical behavior and simple preparation make α-Fe2O3@CeO2 nanostructures an excellent material to be applied in supercapacitors.