TY  - JOUR
AU  - Brisbois, Magali
AU  - Caes, Sébastien
AU  - Sougrati, Moulay T.
AU  - Vertruyen, Bénédicte
AU  - Schrijnemakers, Audrey
AU  - Cloots, Rudi
AU  - Eshraghi, Nicolas
AU  - Hermann, Raphael
AU  - Mahmoud, Abdelfattah
AU  - Boschini, Frédéric
TI  - Na$_{2}$FePO$_{4}$F/multi-walled carbon nanotubes for lithium-ion batteries: Operando Mössbauer study of spray-dried composites
JO  - Solar energy materials & solar cells
VL  - 148
SN  - 0927-0248
CY  - Amsterdam [u.a.]
PB  - NH, Elsevier
M1  - FZJ-2017-00804
SP  - 67 - 72
PY  - 2016
AB  - In order to favor electronic conductivity in sodium iron fluorophosphate electrodes for lithium- or sodium-ion batteries, composites of Na2FePO4F with multi-walled carbon nanotubes (CNTs) were prepared by pilot-scale spray drying. Addition of multi-walled CNTs in the solution results in an excellent dispersion of the CNTs within the volume of Na2FePO4F and not only at the surface of the particles. Following a heat treatment at 600 °C in argon in order to reach crystallization, X-ray diffraction and ex situ Mössbauer spectroscopy revealed the presence of significant amounts of Fe(III) and maghemite (γ-Fe2O3) in the powder. However, Na2FePO4F/CNTs composites exhibit good electrochemical performance when cycling against lithium, with a discharge capacity of 104 mA h g−1 at C/10 rate and 90 mA h g−1 at 1C rate. Therefore, operando57Fe transmission Mössbauer spectroscopy analyses were carried out in order to investigate the evolution of the iron oxidation state during cycling. During the first discharge, all the Fe(III) is reduced to Fe(II), explaining the good electrochemical performance.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000371944500012
DO  - DOI:10.1016/j.solmat.2015.09.005
UR  - https://juser.fz-juelich.de/record/826585
ER  -