Effect of lithium doping on the electrochemical properties of Bi₂Sr₂Co₂O_y misfit-layered oxides for supercapacitor applications

Abstract

The effect of lithium (Li) doping on Bi2Sr2Co2Oy misfit layer oxides for supercapacitor applications is reported for the first time in this research paper. Four different compositions, which included Bi2Li0.1Sr1.9Co2Oy, Bi2Li0.1Sr2Co1.9Oy, Bi2Li0.2Sr1.8Co2Oy, and Bi2Li0.2Sr2Co1.8Oy, were synthesized using a solution combustion method. The obtained powders were further calcined at 900 °C for 10 hours and subsequently characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis and Raman spectroscopy to study the morphology, crystal structure, surface area, elemental identification, quantification, and bonding nature of Li-doped Bi2Sr2Co2Oy. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) were performed for electrochemical characterization to study the effect of Li doping on the charge storage performance of Bi2Sr2Co2Oy. Li doping enhanced the charge storage ability of Bi2Sr2Co2Oy by 3 to 5 fold, and all compositions demonstrated a diffusion-based charge storage mechanism. The Bi2Li0.1Sr2Co1.9Oy solid-state asymmetric device attained the highest specific capacity of 299.6 C/g at 5 mV/s and 241.5 C/g at 1 A/g with 53.7 Wh/kg energy density. Show more