Characterization and Model of Piezoelectrochemical Energy Harvesting Using Lithium ion Batteries

Although lithium ion battery research often focuses on electrochemical properties, lithium ion intercalation materials are also mechanically active. Essentially, these materials exhibit a mechanical-electrochemical coupling such that when a stress is applied, the voltage of the battery increases. In this work, we develop a model to study and predict the effectiveness of intercalation materials as mechanical energy harvesters. Specifically, we show that a lithium ion battery harvester can be modelled as a simple circuit and that we can make both qualitative and quantitative predictions about the effectiveness of a battery material given its intrinsic mechanical and electrochemical properties. The measured efficiency of our system, calculated from the energy output and total work input, is 0.012 +/- 0.004%, and our model predicts that the maximum theoretical efficiency of the system is 2.9 +/- 0.5%. In the future, this model will help us develop and study other intercalation materials that will bring the measured efficiency closer to our proposed theoretical maximum.