The construction of high sulfur (S) loading cathode is one of the critical parameters to obtain lithium-sulfur (Li-S) batteries with high energy density, but the slow redox reaction rate of high S loading cathode limits the development process. In this paper, a metal coordinated polymer-based three-dimensional network binder, which can improve the reaction rate and stability of S electrode. Compared with traditional linear polymer binders, the metal coordinated polymer binder can not only increase the load amount of S through the three-dimensional cross-linking, but also promote the interconversion reactions between S and lithium sulfide (Li2 S), avoiding the passivation of electrode and improving the stability of the positive electrode. At an S load of 4-5 mg cm-2 and an E/S ratio of 5.5 µL mg-1 , the discharged voltage in the second platform is 2.04 V and the initial capacity is 938 mA h g-1 with metal coordinated polymer binder. Moreover, the capacity retention rate approaches 87% after 100 cycles. In comparison, the discharged voltage in the second platform is lost and the initial capacity is 347 mA h g-1 with PVDF binder. It demonstrates the advanced properties of metal-coordinated polymer binders for improving the performance of Li-S batteries.
Keywords: lithium-sulfur batteries; low electrolyte/sulfur ratios; polymer binders; redox reaction.
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