High-performance strontium and bismuth bimetallic oxides electrode：combine first-principles calculations with electrochemical tests

Abstract

A series of bimetallic oxides electrode materials were proposed to boost the supercapacitor performance using the density functional theory (DFT) in combination with the electrochemical tests. This work provides a guiding role for exploring energy storage materials with high performance. Based on the plane wave ultra-soft pseudo-potential (PWPP) and general gradient approximate (GGA) in DFT, the electronic and the crystal structures of various strontium bismuth oxides (β-Bi2O3, SrBi2O4, Sr2Bi2O5 and SrBiO3) were calculated, and the corresponding energy bands were compared. The simulation results show that SrBiO3 has a smaller band gap than the other three oxides, due to the significant hybridization of the electronic density of SrBiO3. The prepared strontium bismuth oxide materials (SrBi2O4, Sr2Bi2O5 and SrBiO3) were characterized using scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD), respectively. In the electrochemical measurement of 6M KOH solution, SrBiO3 presents the highest specific capacity of 810.93F g−1 (i.e. 126.95 mAh g−1) at a current density of 1A g−1. The capacitance retention rate of SrBiO3 is 80.11 % after 2000 cycles, which indicates that it has the useful properties of cyclic stability. All the results suggest that SrBiO3 will be an excellent candidate in electrode materials for the battery-type supercapacitors.