Chemo-Mechanical Effects of Stack Pressure and Temperature on Anode-Free Lithium Metal Batteries

Abstract

Electrochemical cells using rechargeable lithium metal anodes are sensitive to operating temperature and stack pressure. Current understanding generally assumes that temperature drives changes in lithium metal surface chemistry while stack pressure impacts the anode morphology. In this study, we provide quantifiable evidence for these assumptions and propose mechanisms to guide understanding of temperature and pressure effects on lithium metal cell dynamics. Beyond the direct coupling of pressure with mechanics and temperature with kinetics, we also explore possible effects of temperature on cell mechanics and stack pressure on cell chemistry. We investigate an electrolyte composition based on LiDFOB salt, using a range of operando and ex situ techniques. Mechanistic mapping of temperature- and pressure-dependent cell behavior will aid development of improved lithium metal batteries.