Mesoporous Quaternary Ce‐Ni‐Mn–Co Oxides as Electrodematerials forHighPerformance Flexible Solid‐StateAsymmetric Supercapacitors

Abstract Mesoporous quaternary Ce‐Ni‐Mn‐Co oxides microspheres have been successfully prepared by a solvothermal approach and subsequent heat treatment in air.As‐prepared mesoporous quaternary Ce‐Ni‐Mn‐Co oxides microspheres show a large specific surface areas of 146.1 m 2 g ‐1 . When evaluated as an electrode of supercapacitors, the Ce‐Ni‐Mn‐Co oxides microspheres presents an outstanding specific capacitance of 1840.6 F g ‐1 at 1.0 A g ‐1 . Furthermore, a flexible solid‐state asymmetric supercapacitor based on Ce‐Ni‐Mn‐Co oxides was also assembled, which possessed a highenergy density of 0.43 mW h cm ‐3 and good electrochemical stability for 5000 cycles charge‐discharge measurement.Encouragingly, the flexible solid‐state electrochemical energy storage device shows well mechanical flexibility under various bending angles. The excellent electrochemical performances indicate the mesoporous quaternary Ce‐Ni‐Mn‐Co oxides microspheres are promising electrode materials in the energy storage.