A piezoelectric pump for pumping a fluid at a high flow rate includes a housing and an actuator located within the housing. An electric voltage applied to the actuator causes the actuator to apply a force to a first diaphragm that is proximate to the actuator. A piston assembly is located within the housing and is moveable between at least a first position and a second position. A first fluid chamber is defined by the housing, the first diaphragm, and the piston assembly. A coupling fluid is located within the first fluid chamber for coupling the first diaphragm to the piston assembly. A second fluid chamber is defined by the housing and the piston assembly. An inlet valve is in communication with the second fluid chamber and an outlet valve is in communication with the second fluid chamber.