Dopant and Current Rate Dependence on the Structural Evolution of P2‐Na2/3Mn0.8Zn0.1M0.1O2 (M=Cu, Ti): An Operando Study. Issue 6 (24th June 2021)

• Record Type: Journal Article
• Authors: Stansby, Jennifer H.; Sharma, Neeraj; Avdeev, Maxim; Brand, Helen E. A.; Gonzalo, Elena; Drewett, Nicholas E.; Ortiz‐Vitoriano, Nagore; Rojo, Teófilo
• Is Part Of: Chemistry methods. Volume 1:Issue 6(2020)
• Page Start: 295
• Page End: 304
• Publication Date: 2021-06-24
• Subjects: cathode materials -- manganese -- operando studies -- sodium layered oxides -- structural evolution; Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1002/cmtd.202000075
• Languages: English
• ISSNs: 2628-9725

Abstract

Abstract: Variable current rate operando XRD experiments were performed on the P2‐ Na2/3 Mn0.8 Zn0.1 Cu0.1 O2 composition, which displays promising electrochemical properties. The data reveals the reversible formation of a new and previously undetected ordering reflection upon extraction of Na‐ions, and that small compositional alterations may dramatically impact structural evolution and electrochemical properties. For P2‐ Na2/3 Mn0.8 Zn0.1 Cu0.1 O2 at all current rates examined (25, 50 and 100 mA.g −1 ), comparable structural evolution on charge is observed, but the structural evolution on discharge is shown to be significantly influenced by the current applied during the preceding charge step. For both P2‐ Na2/3 Mn0.8 Zn0.1 Cu0.1 O2 and P2‐ Na2/3 Mn0.8 Zn0.1 Ti0.1 O2 comparable structural evolution is observed only at a slower current rate of 25 mA.g −1 . Overall, the structural evolution of these layered materials is shown to be dependent on the cycling history, highlighting the significance of applied current rate during cycling, especially during the initial cycle. Abstract : An ordering reflection at the charged state has been identified using operando X‐ray diffraction for P2‐ Na2/3 Mn0.8 Zn0.1 Cu0.1 O2 . The reflection appears reversibly at the charged state, even when the cell is cycled at different current rates and between different voltage windows. The ordering could be key for a stable layered structure at low Na concentrations found at the charged state of cathode materials during cycling.