Determining the Criticality of Li‐Excess for Disordered‐Rocksalt Li‐Ion Battery Cathodes

The development of Li-excess disordered-rocksalt (DRX) cathodes for Li-ion batteries and interpretation through the framework percolation theory Li diffusion have steered researchers to consider “Li-excess” (x > 1.1 in LixTM2−xO2; TM = transition metal) as being critical achieving high performance. It is shown that this not necessary Mn-rich DRX-cathodes demonstrated by Li1.05Mn0.90Nb0.05O2 Li1.20Mn0.60Nb0.20O2, which both deliver capacity (>250 mAh g−1) regardless their level. By contextualizing finding within broader space DRX chemistries confirming with first-principles calculations, it revealed effect crucial at nanoparticle scale. Instead, lower charging voltage (through formation condensed oxygen species upon oxidation) certain cathodes, otherwise would experience difficulties due very TM-redox potential. findings reveal dual roles – modifying cathode addition promoting must be simultaneously considered determine criticality high-capacity cathodes.