Development of vanadium-based polyanion positive electrode active materials for high-voltage sodium-based batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35835761.
- Also identified by DOI 10.1038/s41467-022-31768-5 and PMC identifier 9283384.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Polyanion compounds offer a playground for designing prospective electrode active materials for sodium-ion storage due to their structural diversity and chemical variety. Here, by combining a NaVPO<sub>4</sub>F composition and KTiOPO<sub>4</sub>-type framework via a low-temperature (e.g., 190 °C) ion-exchange synthesis approach, we develop a high-capacity and high-voltage positive electrode active material. When tested in a coin cell configuration in combination with a Na metal negative electrode and a NaPF<sub>6</sub>-based non-aqueous electrolyte solution, this cathode active material enables a discharge capacity of 136 mAh g<sup>-1</sup> at 14.3 mA g<sup>-1</sup> with an average cell discharge voltage of about 4.0 V. Furthermore, a specific discharge capacity of 123 mAh g<sup>-1</sup> at 5.7 A g<sup>-1</sup> is also reported for the same cell configuration. Through ex situ and operando structural characterizations, we also demonstrate that the reversible Na-ion storage at the positive electrode occurs mostly via a solid-solution de/insertion mechanism.