Formation of Hybrid NiO‐Co ₃ O ₄ ‐MnO ₂ ‐CeO ₂ Hollow Spheres as Advanced Electrode Material for High Performance Supercapacitors

ABSTRACT Hollow structures are perceived as potential candidates in electrochemical energy storage. Although metal oxide with hollow structures has been widely developed, mixed metal oxide is rarely explored due to the challenging preparation method. Herein, the preparation of mixed NiO‐Co 3 O 4 ‐MnO 2 ‐CeO 2 (Ni‐Co‐Mn‐Ce) hollow spheres is realized through a simple route. First, hollow‐textured Ni‐Co‐Mn‐Ce glycerate is achieved under solvothermal condition by quasi‐microemulsion strategy and Ostwald ripening process. Then, the Ni‐Co‐Mn‐Ce glycerate is calcined in air and converted into Ni‐Co‐Mn‐Ce oxide hollow spheres. When Ni‐Co‐Mn‐Ce oxide is applied for supercapacitors, the structure and composition advantages enable it to achieve a considerable capacitance of 1881.6 F g −1 at 4.0 A g −1 , robust rate performance, and only a 6% decline after 6000 continuous times charge–discharge cycles. Furthermore, an asymmetric supercapacitor device fabricated using Ni‐Co‐Mn‐Ce oxide shows an energy density of 69.3 Wh kg −1 at 3299 W kg −1 . When the power density reaches to 16451.1 W kg −1 , the energy density remains at 38.6 Wh kg −1 . This research study provides a way for synthesis of mixed metal oxide hollow structure and provides a promising alternative for supercapacitors.