Chemical Control of Plastic Crystals for Tunable Thermal Energy Storage – ONR
Senior Personnel: P. Shamberger (PI), E. Pentzer (Co-PI)
Under this effort, we focus on identifying and quantifying chemical degrees of control in tunable condensed phase thermal energy storage materials and exploring materials dependencies on the dynamics of the tuning and the energy storage processes. The overarching objective is to develop reversible endothermic condensed phase transitions (solid/solid or solid/liquid) that have dynamically tunable critical transition temperatures, as the basis for responsive and tunable thermal energy storage media. This task will focus primarily on understanding intrinsic chemical degrees of control for three interdependent performance metrics of energy storage materials: (i) dH, the quantity of heat stored in the material, (ii) dTcr/dP the sensitivity of the critical temperature to external pressure, and (iii) t’, the time scale associated with the dynamic tuning of the material.
We will focus on plastic crystals that are known to have relatively large dH and dTcr/dP as model systems, and will focus on three distinctive mechanisms which we anticipate will impact both the change in rotational degrees of freedom and the volume change associated with the plastic crystal. Finally, we will validate the utility of these systems and energy and power density scaling relationships in a prototype energy storage module. The anticipated outcome of these tasks is an approach to design tunable thermal energy storage materials at the molecular level, as well as a validation of their utility as energy storage media.