Interfacial Evaluation in ZnO-Coated NaxMn0.5Fe0.5O2 Cathodes and Hard Carbon Anodes Induced by Sodium Azide: Operando EIS and Structural Insights
Küçük Resim Yok
Tarih
2025
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-V C H Verlag Gmbh
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
This article explores the synthesis and electrochemical properties of NaxMn0.5Fe0.5O2 powders, prepared via a conventional solid-state reaction. Subsequently, the powders are functionalized with a ZnO protective coating through a wet-chemical approach employing zinc acetate in ethanol. Structural characterization confirmed that the ZnO layer maintained the P2-type (P6 3 /mmc) structure, while energy-dispersive X-ray spectrometry mapping verified the successful coating. Electrochemical analyses, including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry, revealed that although the redox reaction mechanism remained unchanged, the charge-transfer resistance (R ct) depended on the coating thickness. ZnO-coated NMFO electrodes exhibited initial discharge capacities of 159.3, 153.6, and 124.8 mAh g- 1 with respective capacity retentions of 48.9%, 41.9%, and 52.0% after 100 cycles for ZnO contents of 0.2, 0.4, and 0.6 wt.%. The galvanostatic intermittent titration technique results indicated that the diffusion coefficients varied with the coating conditions. Operando EIS from 1.5 to 4.3 V showed stable bulk resistance (R b) but voltage-dependent variations in solid electrolyte interface resistance (R SEI) and R ct. Additionally, sodium azide is used to presodiate the hard carbon (HC) anode to enhance the full-cell performance. The ZnO-coated cathode paired with NaN3 presodiated HC delivered a capacity of over 120 mAh g- 1 at C/10. Ex situ analysis after 500 cycles confirmed structural stability, demonstrating that ZnO coating and NaN3 presodiation collectively improve sodium-ion battery performance.
Açıklama
Anahtar Kelimeler
hard carbon, P2-type cathode material, sodium azide, sodium-ion batteries, ZnO coating
Kaynak
Batteries & Supercaps
WoS Q Değeri
Q2
Scopus Q Değeri
Q1
