Perovskite SrCo1-xTixO3-δ as anion-intercalated electrode materials for supercapacitors

Perovskites oxides have recently been widely deployed in supercapacitors though they are suffering from poor electrochemical activity as electrode materials. Herein, a series of Ti-substituted perovskite SrCo 1- x Ti x O 3-δ ( x  = 0, 0.05, 0.10, 0.15, 0.20) are synthesized by solid-state reaction method for anion-intercalated supercapacitor electrode materials. The structural evolution, morphology and the electrochemical performance with the variation of Ti content are characterized in detail. The parent material SrCoO 3- δ contains two phase: a hexagonal structure with space group R 3 ¯ :H (87.09 wt%) and a simple cubic structure with space group Pm 3 ¯ m (12.91 wt%). While a stable cubic structure with Pm 3 ¯ m space group is obtained after Ti substitution and the electrochemical performance is also significantly optimized. A highest specific capacitance ( C s ) of 625.0 F g −1 at 1 A g −1 is achieved in SrCo 0.9 Ti 0.1 O 3-δ sample. The superior electrochemical performance of SrCo 0.9 Ti 0.1 O 3-δ is attributed to the stable cubic structure with higher conductivity and large amount of oxygen vacancy which directly contributes to the anion-intercalated energy storage. In addition, the asymmetric supercapacitor combined with activated carbon electrode exhibits a high specific capacitance of 114.4 F g −1 (50.8 mAh g −1 ) and 98.3 F g −1 (42.7 mAh g −1 ) at 5 mV s −1 and 1 A g −1 , respectively. The device presents an energy density of 69.9 Wh kg −1 at power density of 1600 W kg −1 with a working voltage of 1.6 V.