三种加工方案制备金涂层／PCB型甲醇燃料电池集流体及耐久性

Enhanced durability  of gold－coated current collectors for high power electrochemical devicesWon－Hee RyuKeun－Woo ChoKyung－Sik HongHyuk－Sang Kwon
Abstract
   A highly durable current collector by optimizing the Au electrochemical  deposition conditions is reported． The high corrosion resistance of the Au  layers on the current collector is successfully modified by adjusting the applied current densities and utilizing pulse  potentials． The optimized Au－coated current  collector is evaluated as the electrode substrate  portion of the electrochemical cell．
Fig． 1  （a and b） Surface and （c and d） cross－sectional morphologies of PCB current  collectors coated by Au electroless deposition． The inset of （a） is a  photograph of the PCB current collector； （e） photograph and （f） surface  morphology of the PCB current collector after the cell test．

Fig． 2  Surface morphologies of the electrodeposited Au layers obtained with  different current densities at a total charge of 0．5C cm－2 ： （a） 1 mA cm－2 ，  （b） 3 mA cm－2 ， （c） 5 mA cm－2 ， （d） 10 mA cm－2 ；（e） current efficiency curve  and （f） X－ray diffraction patterns of the electrodeposited Au layers obtained  with different current densities ata total charge of 0．5 C cm－2

Fig． 3  （a） Schematic time vs． applied voltage diagram of pulse electrodeposition；  surface morphologies of the Au layers obtained by pulse electrodeposition at  different peak potentials， （b） 1 V， （c） 1．5 V， and （d） 2 V．

Fig． 4  Anodic polarization curves of the Au－coated PCB current collectors prepared  by （a） constant current electrodeposition conducted with different current  densities and （b） pulse electrodeposition conducted with different peak  potentials． The anodic polarization tests were performed in a 3 M methanol and 1 M H 2 SO 4 solution at room  temperature．

钝化区很宽，腐蚀电流稳定，但是偏大的腐蚀电流是否实用？
Fig． 5  （a） Time course cell power profiles of current collectors employing  electroless－deposited and pulse－deposited Au layers． A 3 M methanol solution  was supplied to the anode， and oxygen was supplied to the cathode．  Cross－sectional morphologies of the current collectors employing （b）  electroless－deposited and （c） pulse－deposited Au layers．

50000s＝833min＝13．8hr
ConclusionsIn  conclusion， the improved durability of the current collector was achieved by  manipulating the Au coating layer on the PCB substrate using the  electrochemical deposition method． We found that the Au coating layer  prepared by electroless deposition showed surface defects， such as pinholes，  and insufficient covering with weak mechanical strength． The durability  of
   the Au coating layer was significantly enhanced using the electrodeposition  method， and the corrosion resistance of the electrodeposited Au layer was  optimized by the applied current
   densities during the constant current electrodeposition of Au． In addition，  the introduction of the pulse electrodeposition method for the Au coating was  more effective than constant
   current electrodeposition due to the higher nucleation rate and smaller  nuclei size， corresponding to better covering properties  and denser coating features． Finally， the PCB  current collector employing the optimized Au layer created by pulse  deposition exhibited a higher cell power performance compared with the  current collector prepared by electroless deposition．