An interactive design for sustainable oxygen capacity in alkali-ion batteries

Abstract

Nonhysteretic and reversible (nHR) oxygen redox is desirable for high-energy-density cathodes in lithium-ion batteries (LIBs); however, serious challenges remain. An interactive design concept that mimics the nHR anionic activity of Li-excess Na oxide for sodium-ion batteries is proposed herein to harness the full potential of the oxygen capacity of Li₂MnO₃ in LIBs. We investigated the reversible stacking sequence transition induced by layer gliding accompanied by oxygen redox during (de)sodiation in Na-layered oxides, with Li ions at the tetrahedral sites of the charged structure. Intriguingly, the stacking transition in F-doped Li₂MnO₃ was identified as a reversible reaction, and the delithiated phase exhibiting no O–O dimers included a consistent Li configuration of the Na cathode. Although in-plane Mn migration resulted in the formation of molecular O₂ trapped in the bulk, the detailed electronic structures in the normal delithiation mode exhibited reversible lattice O(2p) activity.