The free energy of activation of copper electrodeposition from copper sulphate solution is derived in terms of the dehydration energy of copper sulphate, hydration number of copper sulphate, solvated work function of the host metal and coordination number of the host metal on which the copper deposition is carried out. The free energy of activation for copper electrodeposition on 31 different host metals had been evaluated. The trend in the free energy of activation on different metals is studied and feasible electrodeposition of copper for appropriate applications had been suggested. The methodology is extended to obtain the exchange current densities for copper electrodeposition on different surfaces of Pt in acid medium and compared with the existing literature.

Summary A novel pH switch over of the electrolyte in all aqueous Redox Flow Battery (RFB) is studied to augment its voltage efficiency, capacity retention and volumetric capacity. By switching the pH of the anolyte from 2 to 5, the cell voltage stabilized at 0.44 V from 0.85 V vs SHE. pH switch over caused increase in the volumetric capacity from 64 mAh/l to 75 mAh/l. The device showed constant capacity of 40 mAh/l up to 200 cycles with 53% capacity retention. The device performed up to 200 cycles and 720 hours of operation, even in the presence of undesirable side reactions such as Hydrogen Evolution Reaction (HER). Thus by improving the design parameters, one can anticipate all aqueous RFB may be scaled up for practical applications.