Polyoxometalates@Metal-Organic Frameworks Derived Porous MoO3@CuO as Electrodes for Symmetric All-Solid-State Supercapacitor

The demand of uniformity and porosity for composite supercapacitor material has triggered tremendous research efforts for the development of doping method. Herein, we report an effective strategy for homogeneous and polyporous MoO3@CuO composite by heating a POMs@MOFs template (POMs = polyoxometalates, MOFs = Metal-organic frameworks), in which the Mo-POMs are incorporated into Cu-MOFs as secondary building units. The excellent doping of MoO3 to CuO leads to an obvious improvement in specific discharge capacity (from 15.4 mAh g(-1) for CuO to 86.3 mAh g(-1) for MoO3@CuO). The layered structure of MoO3 plays a key role in providing facilitated ion transport and electron diffusion pathways for the composite material. This electrode demonstrates excellent electrochemical performance with a specific discharge capacity of 86.3 mAh g(-1) at 1 A g(-1) in 1 M LiOH. When this porous MoO3@CuO electrode is assembled into a symmetric all-solid-state device with PVA-LiOH gel polymer, the as-fabricated device demonstrates good performance with an energy density of 7.9 W h kg(-1), power density of 8726 W kg(-1), and excellent cycle life. This work presents a new template to improve the uniformity and porosity of composite metal oxides, which can be used for high-performance supercapacitors. (C) 2016 Elsevier Ltd. All rights reserved.