LARBI, Louiza; WERNERT, Romain; FIOUX, Philippe; CROGUENNEC, Laurence; MONCONDUIT, Laure; MATEI GHIMBEU, Camelia

doi:10.1021/acsami.3c01240

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Licence d’utilisation du document

LARBI, Louiza
Institut de Science des Matériaux de Mulhouse [IS2M]

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

FIOUX, Philippe
Institut de Science des Matériaux de Mulhouse [IS2M]

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Article de revue

Ce document a été publié dans

ACS Applied Materials & Interfaces. 2023, vol. 15, n° 15, p. 18992-19001

Washington, D.C. : American Chemical Society

Résumé en anglais

Potassium vanadium oxyfluoride phosphate of composition KVPO4F0.5O0.5 was modified by a carbon coating to enhance its electrochemical performance. Two distinct methods were used, first, chemical vapor deposition (CVD) using acetylene gas as a carbon precursor and second, an aqueous route using an abundant, cheap, and green precursor (chitosan) followed by a pyrolysis step. The formation of a 5 to 7 nm-thick carbon coating was confirmed by transmission electron microscopy and it was found to be more homogeneous in the case of CVD using acetylene gas. Indeed, an increase of the specific surface area of one order of magnitude, low content of C sp2, and residual oxygen surface functionalities were observed when the coating was obtained using chitosan. Pristine and carbon-coated materials were compared as positive electrode materials in potassium half-cells cycled at a C/5 (C = 26.5 mA g–1) rate within a potential window of 3 to 5 V vs K+/K. The formation by CVD of a uniform carbon coating with the limited presence of surface functions was shown to improve the initial coulombic efficiency up to 87% for KVPFO4F0.5O0.5-C2H2 and to mitigate electrolyte decomposition. Thus, performance at high C-rates such as 10 C was significantly improved, with ∼50% of the initial capacity maintained after 10 cycles, whereas a fast capacity loss is observed for the pristine material.< Réduire

Mots clés en anglais

Carbon coating

Chemical vapor deposition

Chitosan biopolymer

Positive electrode material

Vanadium oxyfluoride phosphate

Potassium-ion batteries

DOI

http://dx.doi.org/10.1021/acsami.3c01240

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