Wide Temperature 500 Wh kg ⁻¹ Lithium Metal Pouch Cells

Abstract

The performance of lithium metal batteries is significantly affected by temperature variations, which makes it challenging for them to operate across a wide temperature range. Herein, a wide temperature adaption electrolyte is proposed, enabling excellent electrochemical performance of lithium metal batteries from -40 °C to 60 °C. Large, 5.8 Ah pouch cells employing such an electrolyte achieve high energy density of 503.3 Wh kg^-1 at 25 °C with a lifespan of 260 cycles and outstanding energy density of 339 Wh kg^-1 at -40 °C. The critical role of the solid electrolyte interphase (SEI) in determining the temperature-dependent performance of lithium metal batteries is unveiled. It is demonstrated that the LiF-rich, anion-derived SEI facilitates Li⁺ diffusion in SEI. Moreover, accelerated Li⁺ desolvation at SEI is observed. These two aspects promote the kinetics of lithium metal anodes and further inhibit the dendrite growth at low temperatures. This work showcases the importance of understating the chemistry of SEI to enable wide temperature lithium metal batteries.