A gelatin-based artificial SEI for lithium deposition regulation and polysulfide shuttle suppression in lithium-sulfur batteries

Abstract

Abstract Lithium-sulfur (Li-S) battery is one of the best candidates for the next-generation energy storage system due to its high theoretical capacity (1675 mA h−1), low cost and environment friendliness. However, lithium (Li) dendrites formation and polysulfide shuttle effect are two major challenges that limit the commercialization of Li-S batteries. Here we design a facile bifunctional interlayer of gelatin-based fibers (GFs), aiming to protect the Li anode surface from the dendrites growth and also hinder the polysulfide shuttle effect. We reveal that the 3D structural network of GFs layer with abundant polar sites helps to homogenize Li-ion flux, leading to uniform Li-ion deposition. Meanwhile, the polar moieties also immobilize the lithium polysulfides and protect the Li metal from the side-reaction. As a result, the anode-protected batteries have shown significantly enhanced performance. A high coulombic efficiency of 96% after 160 cycles has been achieved in the Li-Cu half cells. The Li-Li symmetric cells exhibit a prolonged lifespan for 800 h with voltage hysteresis (10 mV). With the as-prepared GFs layer, the Li-S battery shows approximately 14% higher capacity retention than the pristine battery at 0.5 C after 100 cycles. Our work presents that this gelatin-based bi-functional interlayer provides a viable strategy for the manufacturing of advanced Li-S batteries.