Journal article
Boosting the capacity and stability of Na3V2(PO4)2F3-2xO2x microspheres, using atomic layer deposition of artificial CEI
Journal of energy storage, v 84, 111507
15 Apr 2024
Abstract
Phosphate-based materials [e.g. Na3V2(PO4)2F3-2xO2x; (NVPFO2x;0 < x < 1)] are regarded as a promising intercalation cathodes for Sodium-ion batteries (SIBs) due to their high reversible specific capacity and stability. However, so far only 2 Na ion were demonstrated to be active in these polyanionic cathodes, which limit their capacity. Herein we provide a strategic approach towards electrochemical activation of a 3rd Na ion, which leads to higher capacity, and preserves structural integrity. We synthesize and study a series of NVPFO2x (0 < x < 1) with well-controlled surface morphology and vanadium oxidation state, and study the dependence of the electrochemical behavior on the various composition and morphology. The optimized NVPFO cathode exhibited highest initial specific discharge capacity (131 mA h g−1) indicating the activation of 3rd Na ion. Nevertheless, the material suffers rapid capacity fading within ~50 cycles. We demonstrate how this instability is suppressed profoundly through the formation of a thin artificial cathode electrolyte interface (CEI) layer of TiO2 (ca. 2 nm) on the surface of NVPFO by atomic layer deposition (ALD). This TiO2 coating enabled even further extraction of sodium through higher voltage domain, but more importantly, it facilitated excellent long-term stability over 200 cycles. The structural stability of the cathode material was revealed by post cycling HRSEM, XPS, and XRD study. All these studies demonstrate that the thin TiO2 layer effectively contributes to formation of a robust CEI layer, diminishes the parasitic reaction on the electrode surface, reduces carbonate formation, and restricts the electrolyte decomposition.
•Activation of 3rd Na in Na3V2(PO4)2F3-2xO2x; (0 < x < 1) [NVPFO2x] to trigger the performance in Na ion battery.•Stability is improved by a thin protecting layer of TiO2 on NVPFO2x using atomic layer deposition (ALD).•The TiO2 coated NVPFO2x facilitated excellent long-term stability over 200 cycles with discharge capacity of 155 mA h g−1.•The TiO2 layer contributes to form a robust CEI layer, composed of Na-F and Ti–F, preserving the structural stability.
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Details
- Title
- Boosting the capacity and stability of Na3V2(PO4)2F3-2xO2x microspheres, using atomic layer deposition of artificial CEI
- Creators
- Sankalpita Chakrabarty - Bar-Ilan UniversityTali Sharabani - Bar-Ilan UniversitySarah Taragin - Bar-Ilan UniversityReut Yemini - Bar-Ilan UniversityAnanya Maddegalla - Bar-Ilan UniversityIlana Perelshtein - Bar-Ilan UniversityAyan Mukherjee - Bar-Ilan UniversityMalachi Noked - Bar-Ilan University
- Publication Details
- Journal of energy storage, v 84, 111507
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Mechanical Engineering and Mechanics
- Web of Science ID
- WOS:001220667200001
- Scopus ID
- 2-s2.0-85189551448
- Other Identifier
- 991022004769504721
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- Web of Science research areas
- Energy & Fuels