Investigation of NaxFePO4 systems prepared by a modified Pechini sol-gel method as possible cathode materials for high voltage Na-ion batteries
Abstract
An uncomplicated modification of a Pechini assisted sol-gel process in water-polyol solutions is proposed for the synthesis of Na-Fe phosphate powders with different Na-ion content as cathode materials for sodium ion batteries (SIBs). Depending on the pH-values, X-ray diffraction detected the formation of Na-poor olivine-like o-NaFePO4 orthorhombic phase and o-FePO4 nanocrystalline structure. The cyclic voltammetry of the SIBs shows reduction peaks at ~2.23 V (x = 1.0) and ~2.12 V (x = 1.2) vs. Na/Na+ for pH < 3, and between 2.8 V - ~3.0 V (x = 1.0) for pH = 5 respectively. For x = 1.2, several redox peaks observed for pH=5 are assigned to a single-phase reaction (at ~2.5 V vs. Na/Na+) and two-phase reactions (at 3.0–3.25 V). Redox peaks above 4.5 V are more likely associated with Fe3+/Fe4+ redox coupling. A good cyclability is observed for the cathodes synthesized at both the pH values even by charging the batteries to the upper cut-off 4.8 V. The Na-cathode materials prepared under milder conditions showed the highest specific capacity of 40 mAhg-1.
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BibTeX
@misc{dimesso2026investigation,
title = {{Investigation of NaxFePO4 systems prepared by a modified Pechini sol-gel method as possible cathode materials for high voltage Na-ion batteries}},
author = {Lucangelo Dimesso and Lambert Alff and Gennady Cherkashinin},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010502/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010502/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Investigation of NaxFePO4 systems prepared by a modified Pechini sol-gel method as possible cathode materials for high voltage Na-ion batteries
AU - Lucangelo Dimesso
AU - Lambert Alff
AU - Gennady Cherkashinin
PY - 2026
DA - 2026/10/15
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010502/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010502/v1
AB - An uncomplicated modification of a Pechini assisted sol-gel process in water-polyol solutions is proposed for the synthesis of Na-Fe phosphate powders with different Na-ion content as cathode materials for sodium ion batteries (SIBs). Depending on the pH-values, X-ray diffraction detected the formation of Na-poor olivine-like o-NaFePO4 orthorhombic phase and o-FePO4 nanocrystalline structure. The cyclic voltammetry of the SIBs shows reduction peaks at ~2.23 V (x = 1.0) and ~2.12 V (x = 1.2) vs. Na/Na+ for pH < 3, and between 2.8 V - ~3.0 V (x = 1.0) for pH = 5 respectively. For x = 1.2, several redox peaks observed for pH=5 are assigned to a single-phase reaction (at ~2.5 V vs. Na/Na+) and two-phase reactions (at 3.0–3.25 V). Redox peaks above 4.5 V are more likely associated with Fe3+/Fe4+ redox coupling. A good cyclability is observed for the cathodes synthesized at both the pH values even by charging the batteries to the upper cut-off 4.8 V. The Na-cathode materials prepared under milder conditions showed the highest specific capacity of 40 mAhg-1.
ER -