Quantifying the promise of 'beyond' Li-ion batteries

There is a growing consensus that future specific energy improvements in Li-ion batteries may not ever be sufficient to allow mass market adoption of electric vehicles, as we approach the physical limits of storage capacity of current Li-ion batteries. Several 'beyond li-ion' (BLI) chemistries are being explored as possible high-energy-density alternatives to Li-ion batteries. In this article, we focus on analyzing three BLI battery systems: Li-air, Li-sulphur and Na-air. We present a comprehensive discussion of the fundamental material challenges associated with these chemistries and document the progress being made in translating next-generation battery systems from the lab to the market. We also carry out a critical examination of the hype surrounding emerging battery technologies. We report, for the first time, a hype chart for batteries akin to those popularized by Gartner, Inc. for emerging technologies. We expect this hype chart to give us better insights on the respective standings of the current BLI technologies.