Anion-intercalated supercapacitor electrode based on perovskite-type SrB0.875Nb0.125O3 (B = Mn, Co)

The perovskite-type SrMn 0.875 Nb 0.125 O 3 (SMN) and SrCo 0.875 Nb 0.125 O 3 (SCN) materials are prepared through the solid-state reaction method as novel oxygen-intercalated electrode materials for supercapacitor . The crystal structure, powder morphology, and electrochemical performance have been characterized in detail. SMN exhibits a six-layer hexagonal (6 H ) structure with space group P 6 3 / mmc , while SCN shows the tetragonal structure of space group P 4/ mmm . Under the three-electrode system with 1 M Na 2 SO 4 neutral electrolyte solution, the specific capacitance ( C s ) of SCN can reach 894 mF cm −2 at 1 mA cm −2 , which is 4.7 times the value of SMN at the same condition. For SCN, the superiority of electrochemical performance is attributed to its porous surface morphology , perovskite structure with shorter B O bond length and large B-O-B bond angle, and a higher oxygen vacancy content. When combined with activated carbon (AC) electrode, the SCN//AC asymmetric supercapacitor with a working voltage of 2.0 V presents a specific energy density of 82.33 μWh cm −2 , while maintaining prominent cycling stability with a capacity retention of 88.88% after 10,000 cycles.