Rational design of hierarchical crystalline/amorphous hybrid copper tetracyanoquinodimethane and CuWO4 hetero-arrays as effective electrode materials for supercapacitors

Hierarchical core-shell hetero-arrays with well-controlled morphology, rational combination of hybrid electrochemical active materials are regarded as promising candidate electrodes for supercapacitors due to their excellent redox activity and electrical conductivity. However, their inferior rate performance and poor long-term cycling stability hinder their practical applications and still of great challenge. In this work, three hierarchical core-shell CuTCNQ@MWO4/CF (TCNQ = 7,7,8,8-Tetracyanoquinonedimethane; M = Cu, Co and Ni) hetero-arrays on Cu foam with different morphology are successfully constructed by in situ conductive metal-organic framework templated synthetic route of an inter-facial growth and a hydrothermal synthesis process. The crystallinity of MWO4 decorated on the conductive CuTCNQ nanoarrays plays important role in their electrochemical performances. Especially, the hierarchical tree-like CuTCNQ@CuWO4/CF hetero-arrays electrode can be used as high-performance positive electrode materials for supercapacitor, which exhibits excellent electrochemical properties with a high area capacitance (1073.3 mF/cm2 at 1 mA/cm2), excellent rate capability, low resistances and outstanding cycling stability with capacitance retention of 88.6% at 30 mA/cm2 after 10000 cycles. What's more, the CuTCNQ@CuWO4//AC ASC device delivers a high energy density of 0.075 mW h/cm2 (45 W h/kg) at a power density of 0.8 mW/cm2 (480 W/kg) and still achieves a energy density of 0.053 mW h/cm2 (32.1 W h/kg) at a power density of 4.00 mW/cm2 (2424 W/kg). Thus, this work demonstrates that a rational and effective strategy is explored to prepare hierarchical hetero-arrays with different morphology from conductive MOF-templated for high-performance energy storage in practical application.