Characterization of a P2-type chelating-agent-assisted Na_2/3Fe_1/2Mn_1/2O₂ cathode material for sodium-ion batteries

Abstract

A chelating-agent-assisted Na2/3Fe1/2Mn1/2O2 material showed enhanced electrochemical performance due to the formation of a thin and stable solid-electrolyte interface layer.

Characterization of a thin, uniform coating on P2-type Na2/3Fe1/2Mn1/2O2 cathode material for sodium-ion batteries

“…The anodic peaks at around 2.4 V and 3.9 V and cathodic peaks at around 2.0 V and 3.2 V correspond to the intercalation and extraction processes of mobile Na + ions; these values are similar to those in a previous study. 1,6 The sharp increase in the anodic curve at around 4.2 V is related to a quasi-reversible P2-type-to-O2-type phase transition occurring at low Na content in the material. 1,5,6 The lower cathodic peak is related to the Mn redox process, while the higher cathodic peak is from Fe redox.…”

“…The electrical conductivity of the powder sample was measured with the 4-probe method that we have previously developed. 6 Composite positive electrodes comprising 60 wt% active materials, 20 wt% Denka black, and 20 wt% polyvinylidene diuoride (PVDF) were pasted onto an aluminum foil as a current collector. The electrodes were dried at 120 C in vacuum and pressed.…”

Highly Stable Na2/3(Mn0.54Ni0.13Co0.13)O2 Cathode Modified by Atomic Layer Deposition for Sodium‐Ion Batteries

“…[42] The redox peaks centered at voltages of approximately 2.3, 3.6, and 4.3 Vc an be assigned to the electrochemical redox reactions of Mn 3 + /4 + ,C o 3 + /4 + ,a nd Ni 2 + /4 + ,r espectively. [46] The electrochemical oxidative current response area of samples coated by 2A LD cycles was highert han that of the pristine MNC-5 and MNC-10e lectrodes, which demonstrated the excellent electrochemical activity of MNC-2 and is similart ot he additional charging capacity obtainedd uring the C-DC studies. Analogous behavior is observed during the reduction reaction as well.…”

Enhanced Performance of P2‐Na0.66(Mn0.54Co0.13Ni0.13)O2 Cathode for Sodium‐Ion Batteries by Ultrathin Metal Oxide Coatings via Atomic Layer Deposition

“…[2,3,5,7,[13][14][15] So far, Na(Mn 1/3 Ni 1/3 Fe 1/3 ) 2 , NaMO 2 (M = Cr, Fe, Co, and Ni), Na 0.67 Mn 0.65 Fe 0.2 Ni 0.15 O 2 , Na 0.67 (Mn 0.65 Co 0.2 Ni 0. [2][3][4]6,8,10,13,14,16,17] All these materials are known to exhibit large capacities as well as stable cycle life at cut-off voltages below 4.25 V. [2,3,5,7,[13][14][15][16]18] However, many of these materials experience severe capacity decay during charge-discharge cycling at cut-off voltages above 4.3 V. [18,19] The capacity fading during high-voltage operation mainly arises from structural transformations as well as metal dissolution into the acidic electrolyte. [2][3][4]6,8,10,13,14,16,17] All these materials are known to exhibit large capacities as well as stable cycle life at cut-off voltages below 4.25 V. [2,3,5,7,[13][14][15][16]…”