 Highlights this review systematically analyzes the effect of the electrolyte to sulfur ratios on battery energy density and the challenges for sulfur reduction reactions under lean electrolyte conditions. The strengths and limitations of different transition metal compounds are systematically presented and discussed from a fundamental perspective. Three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte-less battery performance. This article was authored by Huipan, Zhibin Cheng, Zhenyu Zhou, and others.