| Copper foil is an important basic material for electronic manufacturing industry and new energy industry,mainly used in printed circuit board and lithium ion battery cathode fluid collector.By adjusting the composition of electrolyte,current density,temperature and additive formula,the related performance of electrolytic copper foil can be regulated,among those strategies,adding additives is an efficient and convenient method.Therefore,this paper investigated the effects of hydrolyzed protein（HVP）,sodium 3-mercaptopropane-1-sulfonate（HP）and sodium N,N-dimethyl thiocarbamide propane sulfonate（DPS）,when acting alone and in combination,on the microstructure and performance of copper foils.The copper foils were prepared in a self-designed plate electrodeposition device of which the operating principles were in accordance with those of actual industrial production.The composition of the basic electrolyte was determined according to the surface morphology,roughness,tensile strength,elongation and other indicators of copper foil.Then the current density,temperature and stirring speed of electrodeposition were tested to determine the optimal process parameters.Finally,the optimal basic electrolyte composition and electrodeposition process parameters were determined as follows:copper ion concentration of 80 g·L-1,sulfuric acid concentration of 100 g·L-1,chloride ion concentration of 50 mg·L-1,current density of 60 A·dm-2,temperature of 323 K,rotating speed of 900 rpm.In this paper,the mechanism of HVP,HP and DPS was studied by chronopotentiometry（E-t）and linear voltammetry（LSV）.The effects of HVP,HP and DPS on the surface morphology and properties of electrolytic copper foil were studied by single additive experiment.The results show that HVP has strong cathodic polarization and grain refinement,which can improve the preferred orientation of（111）crystal plane.Both HP and DPS have strong depolarization,forming HP-Cl and DPS-Cl complexes with chloride ions in the electrolyte.Chloride ions act as salt Bridges to accelerate the growth of crystal nuclei.HP can greatly enhance the preferred growth orientation of copper（200）crystal plane,and DPS can slightly improve the preferred growth orientation of copper（220）crystal plane.Based on the single additive experiment,the optimal combination additive ratio was determined through the combination additive orthogonal experiment:100 mg·L-1 HVP,10mg·L-1 HP and 15 mg·L-1 DPS,and then the combined additives were optimized to investigate the effects of single additive concentration in the additive system on the surface morphology and properties of electrolytic copper foil.According to the surface morphology,roughness,tensile strength,elongation,grain size,crystal structure,resistivity and corrosion resistance of copper foil,the optimal ratio of combined additives is finally obtained:The roughness Rz of the electrolytic copper foil prepared by 80 mg·L-1 HVP,8 mg·L-1 HP and10 mg·L-1 DPS is 1.12μm,tensile strength is 399.5 MPa,elongation is 3.6%,resistivity is3.32×10-6Ω·cm,and corrosion resistance is better.The effects of HVP,DPS and HP on the surface morphology and physical properties of copper foil alone or in collaboration with HVP,DPS and HP have technical guiding significance for the production of ultra-thin and high-performance electrolytic copper foil.Electrochemical analysis showed that HVP had a strong polarization effect,while HP and DPS had a depolarization effect.The strong adsorption of HVP on the cathode surface inhibits the reduction of copper ions and refines the grain.HP has strong depolarization effect,accelerates the filling of the depression on the surface of the coating and improves the smoothness of the coating.The competitive adsorption between DPS and HP enhances the polarization of electrolyte,further refines the grain,and improves the mechanical properties and corrosion resistance of copper foil.The electrodeposition model of the composite additive system was established by analyzing the interaction mechanism of the additives and combining the effects of additives on the surface morphology and physical properties of copper foil. |
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