High-Capacity, Sustainable Lithium–Sulfur Batteries Based on Multifunctional Polymer Binders

Recently, interest in lithium–sulfur batteries has surged due to rapid advances in energy-intensive electric devices. However, despite the high theoretical capacity, natural abundance, and environmental benefits of sulfur, the development of practically viable lithium–sulfur batteries is limited by a short cycle life and poor lithium transport kinetics. Herein, we present a cutting-edge lithium–sulfur battery based on elemental sulfur and multifunctional polymer binders, which can deliver a high specific capacity of 1115 mAh g–1 at 0.5C with a long cycle life of over 550 cycles. The key to this achievement lies in the design of poly(ethylene oxide)-b-poly(4-vinyl catechol) (PEO-b-P4VC) block copolymer binders featuring mussel-inspired adhesive properties combined with improved lithium transport. Effective interchain hydrogen-bonding interactions between P4VC and PEO blocks ensure high elastic properties with a remarkably improved electrochemical stability window of up to 5.4 V. Further, the strong chemical affinity of abundant catechol moieties to polysulfide redox intermediates leads to stable battery performance with high capacity (>1000 mAh g–1), even after 150 cycles at 0.5C, which is superior to any other Li–S batteries comprising elemental sulfur and polymer binders.