Beyond current lithium-ion technologies, magnesium–sulfur (Mg–S) batteries represent one of the most attractive battery chemistries that utilize low cost, sustainable, and high capacity materials. In addition to high gravimetric and volumetric energy densities, Mg–S batteries also enable safer operation due to the lower propensity for magnesium dendrite growth compared to lithium. However, the development of practical Mg–S batteries remains challenging. Major problems such as self-discharge, rapid capacity loss, magnesium anode passivation, and low sulfur cathode utilization still plague these batteries, necessitating advanced material design strategies for the cathode, anode, and electrolyte. This review critically appraises the latest research and design principles to address specific issues in state-of-the-art Mg–S batteries. In the process, we point out current limitations and open-ended questions, and propose future research directions for practical realization of Mg–S batteries and beyond.
This work was supported by the Singapore National Research Foundation (NRF-NRFF2017-04). S.-W.S acknowledges the financial support from the National Research Foundation of Korea (2015062107).