Ultrathin dendrimer–graphene oxide composite film for stable cycling lithium–sulfur batteries

Significance The promise of lithium–sulfur batteries for future electric transportation and stationary energy storage is being limited by their poor cycling stability. Previous approaches to improvement often involve incorporating additional components with significant dead weight or volume in battery structures. We develop an ultrathin functionalized dendrimer–graphene oxide composite film which can be applied to virtually any sulfur cathode to alleviate capacity fading over battery cycling without compromising the energy or power density of the entire battery. The design provides a new strategy for confining lithium polysulfide intermediates and thus stabilizing lithium–sulfur batteries. It also brings a suitable platform for elucidating the underlying materials and surface chemistry.