Dual-ion batteries (DIBs) exhibit a distinct set of performance advantages and disadvantages due to their unique storage mechanism. However, the current cyclability/energy density tradeoffs of anion storage paired with the intrinsic required electrolyte loadings of conventional DIBs preclude their widespread adoption as an alternative to lithium-ion batteries (LIBs). Despite this, their reduced desolvation penalty and low-cost electrode materials may warrant their employment for low-temperature and/or grid storage applications. To expand beyond these applications, this Perspective reviews the prospects of solid salt storage and halogen intercalation-conversion as viable methods to increase DIB energy densities to a level on-par with LIBs. Fundamental limitations of conventional DIBs are examined, technology spaces are proposed where they can make meaningful impact over LIBs, and potential strategies are outlined to improve cell-level energy densities necessary for the widespread adoption of DIBs.
Keywords: dual ion batteries; energy density; energy storage; grid storage; halogen conversion.
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