Study On Preparation And Properties Of Sodium Alginate/Reduced Graphene Oxide Based Electrodes

Based on good biocompatibility and film-forming property of sodium alginate(SA)as well as excellent mechanical strength and electrical conductivity of reduced graphene oxide(rGO),in this paper,a conductive gel was prepared combining SA and rGO.It makes up for the shortcomings of the traditional powder electrode material,which is easy to fall off,difficult to recover and harmful to the environment.Then metal sulfides were loaded to improve the specific capacitance,and the obtained electrodes had excellent electrochemical performance.These electrodes can be assembled into supercapacitor,and have a broad application prospect.In this study,SA/rGO(SrG)based hydrogel was prepared using SA and rGO.The synthetic route combined physical crosslinking and overall reduction.The 3D network structure of the gel can provide sufficient active sites for electrochemical reactions and its electrochemical properties are studied by a series of tests.The electrochemical measurements showed that when 50%graphene oxide(GO)was added,the SrG exhibited the highest specific capacitance of 458 F·g-1(10 mv·s-1)and lowest Rs and Rct as 0.1685 Ω and 0.01208 Ω in the three-electrode system.Thus,the SrG exhibits excellent electrochemical properties and it is a potential electrode material.To improve the electrochemical performance of SrG hydrogels,metal sulfides CuS was loaded on SrG hydrogels matrix to obtain CuS/SA/rGO(CSrG).When the hydrothermal temperature of CuS was 150℃ and the hydrothermal time was 8 h,the electrochemical measurements showed that the prepared CSrG had the highest specific capacitance as 735 F·g-1(10 mv·s-1).When assembled as symmetrical capacitors,the CSrG//CSrG had a specific capacitance of 200.2 F·g-1 at a scan rate of 10 mV·s-1.When the energy density(E)decreased from 5.5 Wh·kg-1 to 3.1 Wh·kg-1,power density(P)increased from 316.8 W·kg-1 to 2750.0 W·kg-1.When assembled as asymmetric capacitors with SrG as negative electrode,electrochemical tests showed that,it had a specific capacitance of 218.2 F·g-1(10 mV·s-1).When the E reduced from 7.3 Wh·kg-1 to 6.0 Wh·kg-1,P increased from 413,1 W·kg-1 to 4000.0 W·kg-1.Thus,the CSrG has outstanding electrochemical properties and can be assembled as supercapacitor.To obtain better electrochemical properties,binary metal sulfide CUCo2S4 was prepared by hydrothermal,calcination and vulcanization.The CuCo2S4/SA/rGO(CCSrG)composite hydrogel was obtained by loading it on the SrG based gel.The electrochemical tests showed that CCSrG showed the highest specific capacitance as 1074 F·g-1(10 mV·s-1)when the hydrothermal temperature and calcination temperature of CuCo2S4 was 120℃ and 450 0C,in the three-electrode system.When assembled as symmetrical capacitors,the CCSrG//CCSrG had a specific capacitance of 237.8 F·g-1(10 mV·s-1).When theE decreased from 31.2 Wh·kg-1 to 4.5 Wh·kg-1,P increased from 317.5 W·kg-1 to 2700.0 W·kg-1.When assembled as asymmetric capacitors with SrG as negative electrode,electrochemical tests showed that,it had a specific capacitance of 283.8 F·g-1 at a scan rate of 10 mV·s-1.When the E reduced from 42.9 Wh·kg-1 to 33.3 Wh·kg-1,P increased from 420.8 W·kg-1 to 4457.1 W·kg-1.Above all,CCSrG as supercapacitor electrode material exhibits great electrochemical performances,so it has good application prospect in the yield of supercapacitor.