Mitigating Metal Dendrite Formation in Lithium–Sulfur Batteries via Morphology-Tunable Graphene Oxide Interfaces

Abstract

Despite issues related to dendrite formation, research on Li metal anodes has resurged because of their high energy density. In this study, graphene oxide (GO) layers are decorated onto Li metal anodes through a simple process of drop-casting and spray-coating. The self-assembly of GO is exploited to synthesize coatings having compact, mesoporous, and macroporous morphologies. The abilities of the GO coatings to suppress dendrite formation are compared through Li|Li symmetrical cell charging at a current density of 5 mA cm–2 for 2000 cycles—a particularly abusive test. The macroporous structure possesses the lowest impedance, whereas the compact structure excels in terms of stability. Moreover, GO exhibits a low nucleation overpotential and is transformed into reduced GO with enhanced conductivity during the operation of the cells; both factors synergistically mitigate the issue of dendrite formation. Li–S batteries incorporating the GO-decorated Li anodes exhibit an initial capacity of 850 mA h g–1 and maintain their stability for 800 cycles at a C-rate of 1 C (1675 mA h g–1), suggesting the applicability of GO in future rechargeable batteries.