WERNERT, Romain; NGUYEN, Long H.B.; IADECOLA, Antonella; WEILL, François; FAUTH, François; MONCONDUIT, Laure; CARLIER, Dany; CROGUENNEC, Laurence

doi:10.1021/acsaem.2c02379

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WERNERT, Romain
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier [ICGM]
Réseau sur le stockage électrochimique de l'énergie [RS2E]

NGUYEN, Long H.B.
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier [ICGM]
Réseau sur le stockage électrochimique de l'énergie [RS2E]

IADECOLA, Antonella
Réseau sur le stockage électrochimique de l'énergie [RS2E]

Langue

Article de revue

Ce document a été publié dans

ACS Applied Energy Materials. 2022, vol. 5, n° 12, p. 14913–14921

ACS

Résumé en anglais

Current performances of Li-, Na-, or K-ion batteries are mainly limited by the specific capacity of the positive electrode. Therefore, it is important to reach the highest capacity possible for a given electrode material. Here, we investigate the performance limitation of KVPO4F, a prospective material for K-ion batteries, which can deliver only 80% of its theoretical capacity. We discover that the capacity limitation of KVPO4F is related to a kinetic competition between K+ deinsertion and side reactions ascribed to the electrolyte degradation at high potentials. Homeotypic VPO4F can be obtained from KVPO4F through a chemical deintercalation process, which disproves a possible structural limitation or instability. The deintercalated compound was characterized by electron and X-ray diffraction, X-ray absorption spectroscopy, and nuclear magnetic resonance spectroscopy. Despite the structural stability, a spontaneous reaction occurs between the deintercalated KxVPO4F (x < 0.5) and the electrolyte (0.8 M KPF6 in ethylene carbonate/diethylene carbonate), with an electron transfer to vanadium compensated by K+ intercalation. This reaction leads to self-discharge until the open circuit potential is lower than 4.7 V versus K+/K, corresponding to the K0.5VPO4F composition.< Réduire

Mots clés en anglais

Vanadium phosphate fluoride

Potassium-ion battery

Chemical deintercalation

Self-discharge mechanism

Side reactions

DOI

http://dx.doi.org/10.1021/acsaem.2c02379

Project ANR

Vers des batteries innovantes K-ion - ANR-19-CE05-0026
Laboratory of excellency for electrochemical energy storage - ANR-10-LABX-0076

Origine

Importé de hal

Unités de recherche

Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) - UMR 5026