LiNO3-free electrolyte for Li-S battery: A solvent of choice with low Ksp of polysulfide and low dendrite of lithium

Although LiNO3 could effectively solve the polysulfide (PS) shuttle problem in Li-S battery, however, it causes explosive hazards with the cathode composition like gun powder (KNO3, Sulfur, and Carbon). Herein, a LiNO3-free electrolyte was designed to simultaneously inhibit the PS shuttle and lithium dendrite problem, with pure 1,3-dioxolane (DOL) as the solvent, due to the low Ksp of polysulfide as well as the stable SEI on lithium. As a synergistic effect, it enabled the Li-S batteries to achieve 95% coulombic efficiency, 3 times longer cycle life, and a slower self-discharging rate at 55 °C compared to the DOL/DME blend solvent. Four kinds of batteries, from coins to soft packages, were carried out to confirm the superiority of this electrolyte. Li-S soft package batteries with 4000 mAh capacity were assembled, achieving the specific energy of 350 Wh kg−1 and specific power of 60 W kg−1, which could cycle over 30 times at 0.2 C with high capacity retention of 80%. It is among the best comprehensive Li-S batteries performance reported using LiNO3-free electrolyte.