Lithiated Spinel LiCo_1–xAl_xO₂ as a Stable Zero-Strain Cathode

We report the discovery of a new zero-strain cathode, LiCo1–xAlxO2 (0 < x ≤ 0.5), which has a lithiated spinel structure synthesized at “low temperature” (LT). Lithiated spinel LiCo1–xAlxO2 operates at the highest average potential (∼3.7 V vs Li) with the lowest volume change (ΔV ≤ 0.02%) ever reported for a zero-strain lithium electrode. Unlike other zero-strain spinel materials such as Li4Ti5O12 and LiRh2O4 that undergo a reversible two-phase reaction, lithiated spinel LiCo1–xAlxO2 electrodes operate by a single-phase process. The study opens the door to the design of a new family of zero-strain materials that can be used as a stable cathode for all-solid-state batteries.