Sulfur synchronously electrodeposited onto exfoliated graphene sheets as a cathode material for advanced lithium–sulfur batteries

Abstract

Lithium–sulfur batteries show fascinating potential applications for rapid-growing electric vehicles and grid-level energy storage due to their low cost and high energy density. To date, various carbon hosts have been utilized to confine sulfur for improving Li–S battery performance. However, the adopted sulfur storage techniques are post-carbon-synthesis involving complex processes. It remains a great challenge to determine the ideal configuration of carbon–sulfur composites with uniform dispersion and high sulfur loading. Herein, we report a novel synthesis of graphene–sulfur composites by electrolytic exfoliation of graphite coupled with in situ sulfur electrodeposition. The sample delivers an initial discharge capacity of 1080 mA h g⁻¹ at 0.1 A g⁻¹ and retains above 900 mA h g⁻¹ over 60 cycles. This strategy via electrochemical exfoliation/deposition synchronous reactions can provide strong sulfur chemical interactions with the graphene host, achieving advanced cathode materials for Li–S batteries.