In this paper, we discuss the effect of potential difference and current density on the crystal morphologies of copper electrodeposits. Their individual roles have been identified by creating a passivation layer in situ at the anode during deposition, which instantaneously reduces the current density in the system while maintaining a high potential difference. It is observed that the crystal shape is decided by the potential difference and current density determines the rate at which that shape is achieved. In a copper system, at high overpotentials, coherent twin boundaries are formed due to their low formation energy as compared to high angle grain boundaries, high index surface planes, etc. Without the presence of any foreign species like H2 bubbles during the crystallization process, the slowest growth direction is identified to be <1 1 1>. The passivation layer is formed due to a pH distribution in the electrolyte caused by the high electric field. A new methodology to explain the formation of the passivation layer is proposed, which is performed by analyzing the current transients generated using Kirchhoff's Laws. © 2017 American Chemical Society.