A universal framework for determining the effect of operating parameters on piezoionic voltage generation†

The piezoionic effect, the generation of a transient voltage in a polymer matrix infused with ion embedded solvent upon the application of a mechanical stimulus, has demonstrated potential applications in ionic sensing, actuation, interfaces, and energy harvesting. Considerable progress has been made to increase voltage output based on optimizing the morphology and composition of materials. However, regardless of the materials used, in order to design and operate piezoionic devices efficiently, the effect of operating parameters, for example, the strength, speed, and location of the mechanical stimulus, as well as the collection of the piezoionic signal using electrodes are of equal importance. Yet, there has not been any systematic exploration of such operating parameters, leading to the present ad hoc approaches to the design, operation, and performance evaluation of piezoionic systems. In this work, we systematically show the effect of operating parameters on piezoionic voltage generation and provide a universal framework to describe new observations. To elucidate the relationship between the piezoionic response and the underlying mechanism, we propose a novel spatial–temporal strategy for characterizing the piezoionic effect. To ensure generality, newfound insights are modeled and cross-validated over a wide range of experimental data. New observations and new theoretical attributions resulting from this work provide the first systematic method towards optimizing the structure, geometry, and test of piezoionic devices.