Unified Picture of (Non)Hysteretic Oxygen Capacity in O3‐Type Sodium 3d Layered Oxides. Issue 28 (1st June 2022)

• Record Type: Journal Article
• Authors: Lee, Jaewoon; Park, Sangeon; Choi, Gwanghyeon; Kwon, Dohyeong; Kim, Jongbeom; Kim, Hyungjun; Cho, Maenghyo; Kim, Duho
• Is Part Of: Advanced energy materials. Volume 12:Issue 28(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-01
• Subjects: first‐principles calculations -- Li‐excess cathodes -- oxygen redox reactions -- sodium‐ion batteries -- voltage hysteresis; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202201319
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: A unified picture of the generalized mechanism that elucidates the (non)hysteretic oxygen capacities of O3‐type Na1− x [Li2/6 Mn3/6 M1/6 ]O2 (M = Mn 4+, Ni 4+, and Ti 4+ ) layered oxides is suggested to provide a critical factor in inducing ideal reversibility for an oxygen redox (OR) reaction using the new concept, the "potential‐pillar" effect. Considering that there is no formation of interlayer oxygen–oxygen (OO) dimers at x = 1.0 in Na1− x [Li2/6 Mn3/6 Ti1/6 ]O2, the phase stabilities reveal that the biphasic reaction occurs in Na1− x [Li2/6 Mn3/6 Ni1/6 ]O2 (0.5 ≤ x ≤ 1.0), and the monophasic reaction takes place in Na1− x [Li2/6 Mn3/6 Ti1/6 ]O2 during desodiation. The electronic structures of cations and anions unambiguously show OR reactions over the full vacancy range, and the oxygen ions comprising TiO6 are relatively deactivated compared with those of NiO6 upon electrochemical OR reaction. This is deemed as an intriguing "potential‐pillar" effect, in which the chemically stiff Ti 4+ (3 d )O(2 p ) bond locally retains a strong electrostatic repulsion between the mixed layers. This unified concept based on an in‐depth understanding of the three cathode models not only accounts for the origin of the (non)hysteretic oxygen capacities, but also provides an exciting local structure viewpoint for harnessing the full potential of OR reactions for high energy‐density sodium‐ion batteries. Abstract : A unified picture that elucidates the (non)hysteretic oxygen capacities in O3‐type Na1− x [Li2/6 Mn3/6 M1/6 ]O2 (M = Mn 4+, Ni 4+, and Ti 4+ ) layered oxides is suggested to provide the new concept, "potential‐pillar" effect. This intriguing concept provides a local‐structure point of view for harnessing the full potential of oxygen redox reactions in sodium‐ and even lithium‐ion batteries.