Why can't this ultrasonic piezoelectric ceramic transducer generate electricity after impact? Is there any way to make this piezoelectric ceramic generate electricity? Its material is PZT.

Piezoelectric ceramics can certainly generate electricity. As long as you put pressure on it, it will produce an electrical signal. The problem is that this kind of battery is so low that it is difficult to be used as a power source. In Japan and Britain, I know someone is studying piezoelectric power generation technology. For example, a large number of ceramic pieces are laid under the road surface to collect the pressure generated by cars and people to generate electricity.