Controllable Preparation And Properties Of Electrode Materials Based On Juglone And NiCo₂O₄ For Supercapacitors

Recently,great efforts have been devoted to design and fabricate flexible,lightweight,wearable and miniaturized supercapacitors.Meanwhile,the rational exploration of green,renewable and bio-compatible energy-storage materials is attracting intensive attention.Taking fabrication and configuration design into consideration,we exploit the naturally derivable juglone molecule as the active charge-storage material,and integrate it into ideal flexible and micro supercapacitor devices.The PPy/juglone composite based supercapacitors exhibit significant energy storage capabilities with high specific capacitance and long cyclability,which are comparable to that of conventional electrode materials.The as-prepared juglone incorporated polypyrrole（PPy）composite electrode shows high specific and areal capacitance as high as 936 F g^-1 and 206 mF cm^-2,repectively,and the symmetrical flexible and micro supercapacitor devices based on this conjugated polymer/biomaterials also exhibit high capacitances and high rate capabilities comparble to other man-made conventional materials.Our work presents a new way for developing flexible,lightweight,portable and/or wearable electronic devices with bio-compatible and environmentally friendly attributes.Among numerous active electrode materials,nickel cobalt oxide materials are promising electrode in electrochemical capacitors.In this paper,a simple and green electrochemical method was used to synthesize high-purity ultra-thin nickel-cobalt cobalt nanoplates and apply them into supercapacitors.Through a series of characterization and measurements,we demonstrated that NiCo₂O₄ nanosheets possess excellent electrochemical performance and electrodes exhibit high capacitanceof 848.6 F g-1,Compared to materials reported in literature,NiCo₂O₄ is more suitable as high specific capacitance and high energy density and power density of advanced electrode materials for supercapacitors.Meanwhile,the material has a long cycle life（94.7%charge retention rate after 5,000 times）,presenting its broad application prospect as high-performance supercapacitor,In addtion,this work paves a new avenue for the research of other energy storage devices.