Turning on Lithium-Sulfur Full Batteries at -10 °C

Abstract

Lithium-sulfur (Li-S) batteries using Li₂S and Li-free anodes have emerged as a potential high-energy and safe battery technology. Although the operation of Li-S full batteries based on Li₂S has been demonstrated at room temperature, their effective use at a subzero temperature has not been realized due to the low electrochemical utilization of Li₂S. Here, ammonium nitrate (NH₄NO₃) is introduced as a functional additive that allows Li-S full batteries to operate at -10 °C. The polar N-H bonds in the additive alter the activation pathway of Li₂S by inducing the dissolution of the Li₂S surface. Then, Li₂S with an amorphized surface layer undergoes the modified activation process, which consists of the disproportionation and direct conversion reaction, through which Li₂S is efficiently converted into S₈. The Li-S full battery using NH₄NO₃ delivers a reversible capacity and cycling stability over 400 cycles at -10 °C.

Keywords: Li2S cathode; electrolyte additive; full cell; lithium−sulfur batteries; low-temperature.