Self-Template Synthesis of Hybrid Porous Co3 O4 -CeO2 Hollow Polyhedrons for High-Performance Supercapacitors.

In this work, hybrid porous Co3 O4 -CeO2 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 Co3 O4 -CeO2 hollow polyhedrons. When utilized as electrode materials for supercapacitors, the hybrid porous Co3 O4 -CeO2 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 Co3 O4 -CeO2 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.