Study On The Electrode Materials Of Cobalt, Manganese And Nickel(Hydroxide) Oxide Base For Supercapacitor

To meet the development demand for high energy density and integration of supercapacitor,it's very urgent to prepare electrode materials with high capacitance and long cycle-life.Cobalt/manganese/nickel hydroxide/oxide have been regarded as the most promising electrode materials for their advantages of high theoretical capacitance and physical-chemical stability.Therefore,it's of great significant to study these materials.MnO2,Co3O4 and Co(OH)2 material were prepared by precipitation and in-situ growth method,respectively.The effects of variables of process parameters(material type and heat treatment temperature),doping agent type and doping amounts on materials' microstructures and electrochemical properties were investigated.Materials' crystal structure and morphology was characterized by XRD and SEM,respectively.Materials' electrochemical properties were tested on an electrochemical workstation.MnO2 material gained by manganese acetate exhibits a well electrochemical performance.The material with a Mn/Co mole ratio of 50:1 and a Mn/Cr mole ratio of 20:1 displays the highest specific capacitance of 116.6 F/g(promoting 20%)and 144.26 F/g(promoting 33%)at 200 m A/g and a capacitance retention of 101.69% and 86% after 2500 cycles at 100 m V/s,respectively.Heat treatment temperature affects the optimum doping ratio of nickel-doped Co3O4 material,and the temperature of 200 oC,220oC and 290 oC corresponds to the Ni/Co mole ratio of 1:3,1:6 and 1:3,respectively.The material at a Ni/Co mole ratio of 1:6 at 220 oC and 1:3 at 200 oC shows the highest specific capacitance of 769.16 F/g at 200 m A/g and 290 F/g at 10 A/g,respectively.Co(OH)2 gained by ammonium nitrate has a well electrochemical property.The material with a Co/Ni and Co/Mn molar ratio of 3:1 has the highest capacitance of 1340 F/g and 2489.09 F/g(4.19 and 3.04 times of the pure)at 10 A/g and a capacitance retention of 68.7% and 88.33% after 5000 cycles at 20 A/g and 100 A/g,respectively.