Progress in electrolytes for rechargeable Li-based batteries and beyond

TLDR

Li‑based batteries dominate portable electronics and electric vehicles because of their high volumetric energy density, yet electrolyte development is becoming critical for power density, long‑term stability, and solid electrolyte interface formation. This review surveys five classes of room‑temperature electrolytes for Li batteries—non‑aqueous, aqueous, ionic liquid, polymer, and hybrid—to guide future design. It also briefly examines electrolytes for non‑Li chemistries such as Na, Mg, Ca, Zn, and Al batteries.

Abstract

Owing to almost unmatched volumetric energy density, Li-based batteries have dominated the portable electronic industry for the past 20 years. Not only will that continue, but they are also now powering plug-in hybrid electric vehicles and zero-emission vehicles. There is impressive progress in the exploration of electrode materials for lithium-based batteries because the electrodes (mainly the cathode) are the limiting factors in terms of overall capacity inside a battery. However, more and more interests have been focused on the electrolytes, which determines the current (power) density, the time stability, the reliability of a battery and the formation of solid electrolyte interface. This review will introduce five types of electrolytes for room temperature Li-based batteries including 1) non-aqueous electrolytes, 2) aqueous solutions, 3) ionic liquids, 4) polymer electrolytes, and 5) hybrid electrolytes. Besides, electrolytes beyond lithium-based systems such as sodium-, magnesium-, calcium-, zinc- and aluminum-based batteries will also be briefly discussed.