Enabling Sodium Batteries Using Lithium‐Substituted Sodium Layered Transition Metal Oxide Cathodes

Layered Na0.85Li0.17Ni0.21Mn0.64O2 is synthesized and evaluated as a cathode in Na batteries. The resulting P2 crystal structure allows for single-phase reversible Na intercalation reaction demonstrating 100 mAhg−1. The cathode can be discharged with high rate (65 mAhg−1 at 25 C rate). The presence of Li and the electronic ordering of Ni(II)/Mn(IV) in the transition metal layer is responsible for material stability.