A comprehensive study of Bi2Sr2Co2Oy misfit layered oxide as a supercapacitor electrode material.

[Display omitted] • Bi 2 Sr 2 Co 2 O 9 was successfully synthesized via sol–gel combustion method. • Prepared electrodes showed good electrochemical performance. • The maximum specific capacity of 166.6C × g−1 at 2 mVs−1 scan rate was attained for BSC-10 sample. • Bi 2 Sr 2 Co 2 O 9 has a capability to use as supercapacitor electrode material with its thermos-electric property. Recently, the development of multiple functional energy storage materials having high energy storage capacity, expanded stability, and cost-effectiveness with eco-friendly nature is primary choice. Bi 2 Sr 2 Co 2 O y (BSC-222) is misfit-layered oxide having significant thermoelectric (TE) capability with high temperature stability and eco-friendly characteristics. In present work, we successfully synthesized misfit layered BSC-222 oxide by using sol–gel method. X-ray diffraction, scanning electron microscopy, and atomic force microscopy are used to describe the structure and morphology of calcined BSC-222. Average thickness of prepared oxide sheets was found to be ∼30 to ∼40 nm. By using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 3 M KOH, the electrochemical analysis of produced BSC-222 electrodes was carried out. The CV and GCD analysis showed that the BSC-222 oxide having high secondary cobaltite phases has better charge storage capacity (166.6C × g−1) at 2 mVs−1 and majorly charge is stored through diffusion-controlled charge storage mechanism. A chemical reactions schematic is proposed for the charge storage mechanism. Moreover, this calcined BSC-222 exhibits better cycling stability of 68.8 % up to 5000 GCD cycles at 1.5 Ag−1 current density. Hence, BSC-222 misfit layered oxide demonstrates that it has capability to store charge with its good TE ability. This present work provides the first step towards utilizing good TE misfit layered materials even after some doping or modulation in their structure to fabricate high energy density energy storage devices with multifunctional characteristics. [ABSTRACT FROM AUTHOR]