Self‐Template Synthesis of Hybrid Porous Co3O4–CeO2 Hollow Polyhedrons for High‐Performance Supercapacitors

Abstract In this work, hybrid porous Co 3 O 4 –CeO 2 hollow polyhedrons have been successfully obtained via a simple cation‐exchange route followed by heat treatment. In the synthesis process, ZIF‐67 polyhedron frameworks are firstly prepared, which not only serve as a host for the exchanged Ce3 + ions but also act as the template for the synthesis of hybrid porous Co 3 O 4 –CeO 2 hollow polyhedrons. When utilized as electrode materials for supercapacitors, the hybrid porous Co 3 O 4 –CeO 2 hollow polyhedrons delivered a large specific capacitance of 1288.3 F g −1 at 2.5 A g −1 and a remarkable long lifespan cycling stability (<3.3 % loss after 6000 cycles). Furthermore, an asymmetric supercapacitor (ASC) device based on hybrid porous Co 3 O 4 –CeO 2 hollow polyhedrons was assembled. The ASC device possesses an energy density of 54.9 W h kg −1 , which can be retained to 44.2 W h kg −1 even at a power density of 5100 W kg −1 , indicating its promising application in electrochemical energy storage. More importantly, we believe that the present route is a simple and versatile strategy for the preparation of other hybrid metal oxides with desired structures, chemical compositions and applications.