Mechano-Electrochemistry for Advanced Energy Storage and Harvesting Devices

Abstract

A fundamental perception in the energy storage community is that mechanical processes accompanying electrochemical processes are an unavoidable by-product. However, the coupling between mechanics and electrochemistry termed as the ‘mechano-electrochemical coupling’ is a powerful yet unexplored tool. Using principles of elastic strain engineering, we demonstrate controllable modulation of electrochemical parameters governing energy storage systems. Leveraging the shape memory properties of NiTi alloys, redox potentials and diffusion coefficient modulations for energy storage materials were achieved as a function of applied strain. Building off these principles, we developed electrochemical-mechanical energy harvesters for harnessing ambient mechanical energy at very low frequencies (<5 Hz), a regime where the conventional state-of the art piezoelectric and triboelectric energy harvesters have drastically reduced performances. We also highlight frequency tuning capabilities in this class of energy harvesters owing to the inherent differences in various battery electrode chemistries for use in human motion harvesting and sensing applications and multifunctional transient energy harvesting and storage devices. Additionally, to further illustrate the relationship between mechanical and electrochemical properties, we developed multifunctional structural supercapacitor and battery composites for use in load-bearing applications. Overall, these approaches provide paradigm shifting fundamental insights as well as create a framework for developing such multifunctional energy storage/harvesting architectures for a multitude of applications.