Study On Preparation Of Molybdenum Based Asymmetric Supercapacitor Electrode By Inkjet Printing And Its Properties

The development and optimization of supercapacitors（SCs）electrode material is the key to preparing high-performance SCs.The capacitance of transition metal oxide/sulfide on the electrode surface is much greater than the double layers capacitor with its own physical adsorption,but the low conductivity and poor structural stability limit its development.In addition,inkjet printing technology can prepare the dispersion of different nanomaterials（known as ink）into the energy storage system electrode on the fluid surface through digital control,but the dispersion stability of ink is the primary problem to be solved.This paper investigated the transition metal oxide Mo O₂.Ag_x/Mo O₂ nanoparticles,Ni₃S₄/Mo O₂ and NiCo₂S₄/Mo O₂ nanocomposites were prepared by solvothermal,and stable inks were prepared by analyzing their microscopic properties.Thin-film electrodes were prepared on the rGO@NF conductive substrate surface using inkjet printing and further assembled into asymmetric supercapacitors to study their electrochemical properties.The details are as follows:1.Nickel foam（NF）was used as the fluid collector,with a layer of GO on its surface and then reduced to rGO in hydralazine,and prepared into rGO@NF conductive substrate for backup.The rGO acted as an active substance and a fluid collector（NF）,avoiding the addition of binders and reducing additional resistance.Moreover,its lamellar structure can provide more attachment points for micro-nanoparticles and increase the amount of attachment.Ag_x/Mo O₂ nanomaterials with different Ag content（X=0,1%,3%,5%,7%）were prepared with precious metal Ag modification by solvothermal,and Ag_x/Mo O₂@NF electrodes were prepared by inkjet printing technology,and the optimal Ag content was 5%.Then,the inkjet printing technology was used to make the Ag_0.05/Mo O₂/rGO@NF current density is 1 A/g,the specific capacity is 316.9 C/g;when the current density increases to 5A/g,the specific capacity is 290.1 C/g,and the capacity retention rate is 91.5%.After 3,000cycles of charge and discharge,the specific capacity retention rate is 75.4%,showing the high multiplier performance and cycle stability of the electrode.It was assembled as a positive electrode into an asymmetric supercapacitor.When the power density is 576 W/kg,the energy density is 14.11 Wh/kg;after 2,000 cycles stability tests,the specific capacity can retain88.6%.2.The rGO@NF conductive substrate was prepared by inkjet printing technology combined with solvothermal.Ni₃S₄ was considered as a potential pseudocapaciance material for shell,Ni₃S₄/Mo O₂ nanomaterials of nuclear shell structure were prepared by solvothermal,the redox behavior of Ni atoms and the conductivity of Mo atoms can act together to produce high specific capacity.Ni₃S₄/Mo O₂/rGO@NF electrodes were prepared on the rGO@NF conductive substrate surface by the inkjet printing technique.After testing,the specific capacity is 663.6 C/g when the current density is 1 A/g.After 3000 cycles of charge and discharge,the specific capacity retention rate is 80.2%.After assembly into an asymmetric supercapacitor,the energy density is 51.36 Wh/kg,when the power density reaches 588.5W/kg.After 2,000 cycles of charge and discharge,the specific capacitance retention rate reached 82.8%.3.The rGO@NF conductive substrate was prepared by inkjet printing technology combined with solvothermal.Unary transition metal sulfide Ni₃S₄ was replaced with binary transition metal sulfide NiCo₂S₄ to improve electrical conductivity and structural stability,NiCo₂S₄ has higher redox-reactive electric pairs and presents a higher specific capacity.NiCo₂S₄/Mo O₂ nuclear-shell structure nanomaterials were prepared by solvothermal,and NiCo₂S₄/Mo O₂/rGO@NF electrodes were prepared by inkjet printing technology.After testing,the specific capacity could reach 753.3 C/g at a current density of 1 A/g,and the retention rate is 82.3%.Assembling asymmetric supercapacitors,when the power density reaches 987.1 W/kg,the energy density is 54.81 Wh/kg.After 2,000 cyclic of charge and discharge tests,the specific capacitance retention rate is 85.7%,which has good multiplier performance and cycle stability.