MXene/rGO/sulfur loaded separator based current collector-free lithium sulfur batteries with high sulfur loading and cycle life

Abstract

Lithium-Sulfur batteries with high sulfur loading cathodes are highly desirable to achieve greater energy density. In this work, a high loading composite cathode is reported that is made by scalable vacuum filtration route, eliminating the need for a binder, conducting carbon, and metallic current collector. Moreover, capacity fade due to peeling off of coated active material from current collector is avoided, leading to excellent capacity retention. The coated separator affords a porous framework to (i) accommodate volume changes during cycling, (ii) allow higher sulfur loading, (iii) allow electrolyte wetting of active material in addition to (iv) functioning as a traditional separator and current collector by pressing against stainless steel casing. The MXene/reduced graphene oxide/S8 composite with an areal loading of 2.52 mg/cm2 exhibits a specific capacity of 495 mAh/g with a capacity retention of 97.5% after 200 cycles at a charge/discharge rate of 100 mA/g. At 500 mA/g discharge rate, an initial specific capacity of 378 mAh/g was obtained with 239 mAh/g retained after 750 cycles.