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

The perovskite-type SrMn0.875Nb0.125O3 (SMN) and SrCo0.875Nb0.125O3 (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 (6H) structure with space group P63/mmc, while SCN shows the tetragonal structure of space group P4/mmm. Under the three-electrode system with 1 M Na2SO4 neutral electrolyte solution, the specific capacitance (Cs) 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 mu Wh cm-2, while maintaining prominent cycling stability with a capacity retention of 88.88% after 10,000 cycles.

Automated summary

The perovskite-type SrMn0.875Nb0.125O3 (SMN) and SrCo0.875Nb0.125O3 (SCN) materials prepared by solid-state reaction method exhibit different crystal structures and electrochemical performances, with SCN showing higher specific capacitance under the same conditions.