Markets for energy storage that go beyond portable electronics have emerged rapidly this decade, including powering electric vehicles and “leveling the grid” fed by renewable sources such as solar energy, which are intermittent in supply. These new demands require a significant step-up in energy density that will probably not be met by Li-ion batteries; estimates suggest they are starting to approach their theoretical limits. But in the world of “beyond Li-ion,” the options are limited. One of the most hopeful is the Li-S battery, for which greater energy storage can potentially be realized through phase-transformation chemistry using elemental sulfur as a positive electrode material, which converts to lithium sulfide. These future generation systems offer up to a five-fold increased specific energy and greatly reduced cost factors, but commercialization has been hindered owing to key challenges. Efforts over the last two years to better manipulate the cell chemistry and overcome these challenges are presented.