The term piezo-electrical smart materials refers to a class of materials that can generate an electrical charge in reaction to mechanical pressure or stress, and vice-versa, where they can deform or move in response to an electrical field. Piezo-electrical materials have the inherent capability to convert mechanical power into electrical power and vice-versa. The term smart refers to the fact that these materials can sense and react to external stimuli in a controlled and accurate manner. These materials are used in a wide range of applications, from sensors and actuators to energy and energy-harvesting systems and vibration control.