Premium
Highly Reversible Oxygen‐Redox Chemistry at 4.1 V in Na 4/7− x [□ 1/7 Mn 6/7 ]O 2 (□: Mn Vacancy)
Author(s) -
Mortemard de Boisse Benoit,
Nishimura Shinichi,
Watanabe Eriko,
Lander Laura,
Tsuchimoto Akihisa,
Kikkawa Jun,
Kobayashi Eiichi,
Asakura Daisuke,
Okubo Masashi,
Yamada Atsuo
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800409
Subject(s) - redox , cathode , oxygen , intercalation (chemistry) , materials science , oxide , transition metal , inorganic chemistry , chemical physics , metal , chemistry , catalysis , organic chemistry , biochemistry , metallurgy
Increasing the energy density of rechargeable batteries is of paramount importance toward achieving a sustainable society. The present limitation of the energy density is owing to the small capacity of cathode materials, in which the (de)intercalation of ions is charge‐compensated by transition‐metal redox reactions. Although additional oxygen‐redox reactions of oxide cathodes have been recognized as an effective way to overcome this capacity limit, irreversible structural changes that occur during charge/discharge cause voltage drops and cycle degradation. Here, a highly reversible oxygen‐redox capacity of Na 2 Mn 3 O 7 that possesses inherent Mn vacancies in a layered structure is found. The cross validation of theoretical predictions and experimental observations demonstrates that the nonbonding 2p orbitals of oxygens neighboring the Mn vacancies contribute to the oxygen‐redox capacity without making the Mn−O bond labile, highlighting the critical role of transition‐metal vacancies for the design of reversible oxygen‐redox cathodes.