Preparation And Supercapacitive Properties Of The Bimetallic Co-Mo-based Electrode Materials

Supercapacitor has been widely studied as a novel energy storage equipment,owing to the advantages including the high power density,long cycle life and environmental friendliness.The main component electrode material plays the important role in supercapacitor performances.Transition metal compounds are widely used as electrode materials of supercapacitors,due to their high theoretical specific capacity.In this paper,the Co and Mo based bimetallic compounds are treated as the main research object,and their supercapacitor performances are improved by controlling the material morphology,and preparing the nano and composite materials.The main research contents are as follows:(1)The ultrathin nanosheets constructed Co Mo O4 microspheres are prepared by a simple chemical precipitation with urotropin as the soft template.After the electrochemical tests,the prepared Co Mo O4 sample exhibits the upmost supercapacitor performances such as the specific capacity of 89 m A/h at 0.25 A/g.Meanwhile,the Co Mo O4//AC hybrid supercapacitor device is assembled,which can exhibit the specific energy of 34 Wh/kg at the specific power of 375 W/kg,and excellent cycle stability such as no obvious decay after 10,000 charge/discharge cycles for specific capacity.(2)The Co Mo S4-derived Co9S8@Mo S2 composite was prepared though adjusting the reaction temperature in a simple one-step hydrothermal method,and controlling the grain growth by adding ammonium fluoride.Further,the Co9S8@Mo S2 composite shows the good supercapacitor performances such as the specific capacity of 213 m Ah/g at 1 A/g.Moreover,the assembled Co9S8@Mo S2//AC hybrid supercapacitor has a high energy density of 42 Wh/kg at 375 W/kg,and even the energy density of 25 Wh/kg at a high power density of 2250 W/kg.Meanwhile,there is no obvious decay for capacity retention after 9000 charge/discharge cycles.(3)The Co Mo S4/Ti3C2 composite materials were prepared by using Ti3C2 as raw material through hydrothermal synthesis,and used as the supercapacitor electrode material.At the current densities of 0.5?1.0?1.5?2.0?2.5?3.75 and 5 A/g,the specific capacitances of this composite material are 348?260?183?152?135?107 and 86 F/g,respectively.In addition,the assembled Co Mo S4/Ti3C2//AC hybrid supercapacitor can exhibit the energy density of 33.33 Wh/kg at a power density of 375 W/kg,and the capacity retention of 90%after 4000 charge/discharge cycles.