Temperature-dependent viscoelastic liquid MOFs based cellulose gel electrolyte for advanced lithium-sulfur batteries over an extensive temperature range

The uncontrolled growth of lithium dendrites severely limits the practical use of Li-S batteries. Additionally, cell temperature increases during operation, accelerating dendrite growth and side reactions. To stabilize the anode over a wide temperature range, we proposed a promising solution of a novel temperature-dependent viscoelastic liquid UiO66 MOFs-based cellulose gel electrolyte. This specially engineered electrolyte demonstrated superior stabilization of the anode. It adopted the "blocking anions and promoting Li+ transfer" strategy, resulting in a uniform Li+ flux deposition and the formation of a stable and dense solid electrolyte interphase layer, effectively suppressing dendrite growth. To further improve the cycling performance of the cell, a hollow transition bi-metal selenide (FeCo-Se2/NC) was developed as the sulfur host material. This complex exhibited a strong chemisorption capacity for polysulfides and a high catalytic ability to expedite the conversion process of lithium polysulfides. The final cell achieved a high capacity of 687.2 mAh g-1 after 500 cycles at 3 C with a minimal fading rate of 0.04 % per cycle. It also demonstrated a high area capacity of 5.78 mAh cm-2 at a high sulfur loading of 6.2 mg cm-2, along with excellent cycling stability under temperature-varying conditions. The findings not only highlighted the commercialization potential of Li-S batteries but also underscored the effectiveness of porous liquid MOFs as a modified layer, effectively stabilizing the Li anode and reducing interfacial impedance between the electrolyte and electrode. Our research paved the way for advanced energy storage solutions that could significantly contribute to a sustainable and eco-friendly future.