Spintronic State‐Induced Interface Reconfiguration of 2H‐Perovskite Related Oxides for Pseudocapacitance Increase.

Perovskite oxides are able to realize pseudocapacitive energy storage through oxygen anion intercalation. Herein, it is demonstrated that, based on the three 2H‐perovskite related oxides Sr6Co5O15‐x, Sr5Co4O12‐x, and Sr5Co3NiO12‐x as the research objects, metal oxyhydroxides generated through surface reconfiguration during electrochemical processes can contribute extra capacity besides the oxygen‐anion intercalation. This is because the electron spin state controlled by the transition metal valence state in the pseudo trigonal prisms for the 2H‐perovskite structure will affect the Jahn–Teller (JT) distortion. The strong JT distortion of Co2+ and Ni3+ would elongate metal‐O bonds, thereby helping the formation of metal oxyhydroxides on the surface of the pristine material. Among the three 2H‐perovskite related oxides, the specific capacity of Sr5Co3NiO12‐x having the most Co2+ and Ni3+ contents showed the highest capacity increase. This study will provide a promising pathway to develop advanced perovskite‐like oxide pseudocapacitive materials. [ABSTRACT FROM AUTHOR]