Temperature‐Dependent Electrochemical Performance of Ta‐Substituted SrCoO3 Perovskite for Supercapacitors

Abstract

AbstractDeveloping new electrode materials with good temperature‐dependent electrochemical performance has become a great issue for the deployment of hybrid supercapacitors with wide temperature tolerance. In this work, a series of Ta‐substituted SrCo1‐xTaxO3‐δ (x=0.05, 0.10, 0.15, 0.20) perovskites have been studied as positive electrodes for hybrid supercapacitors in terms of their structures, elemental valence states and electrochemical performances. Incorporating Ta into SrCoO3‐δ perovskite not only stabilizes the crystallite structure but also notably improves electrochemical activities. The SrCo0.95Ta0.05O3‐δ@CC delivers the highest specific capacity (Qsp) of 227.91 C g−1 at 1 A g−1, which is attributed to the highest oxygen vacancy content and the fastest oxygen diffusion kinetics. The hybrid supercapacitor SrCo0.95Ta0.05O3‐δ@CC//AC@CC exhibits a high energy density of 22.82 Wh kg−1@775.09 W kg−1 and a stable long‐term cycle life (5000 cycles) with 90.7 % capacity retention. As temperature increases from 25 to 85 °C, the capacitance properties are improved at elevated temperatures for both electrode and device due to the increased electrolyte conductivity. The outstanding electrochemical results present that SrCo1‐xTaxO3‐δ perovskite holds good prospects for hybrid supercapacitors with wide temperature tolerance.