Binder, J.R.

Doyle, S.

Geßwein, H.

Glatthaar, S.

Moenig, R.

Binder, J. R.

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KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association Conclusions  SXRD is a powerful tool for in situ studies of Li ion batteries. XRD can monitor phase evolution, change of lattice parameters, microstructure and long range order.  Cation and/or anion substitution in lithium manganese oxide based spinel materials greatly affects the electrochemistry and cycle behaviour of the cathode. Fluoride substitution changes phase behaviour in the 4 – 5 V region.  Fluoride substitution induces partial supression of the tetragonal Jahn-Teller distortion and a reduction of strain in the structure (<c/a). In situ X-ray diffraction studies of Fe/F co-doped LiNi0.5Mn1.5O4 spinel cathodes H. Geßwein, S. Glatthaar, R. Moenig. S. Doyle, J. R. Binder Li-ion battery  LiNi0.4Mn1.5Fe0.1O4 Institute for Applied Materials Particles(LiFePO4)+ Binder+ CarbonBlackAl foil1µmBinder (Polymer)Carbon BlackActive materiale.g. LiCoO2 , LiMn2O4, LiFePO4Whittingham, MRS Bulletin 33 (2008), 411 Cell reaction: Li1-xMO2 + LixCn       LiMO2 + Cn  D C →← In situ SXRD @ ANKA PDIFF  • X-ray beam size 500x250 μm2, λ = 0.8853 Å • Data collection time 30 s per diffraction pattern  • Sample-detector-distance: 23 cm • Pilatus 300K-W detector Results  LiNi0.4Mn1.5Fe0.1O4  LiNi0.5Mn1.4Fe0.1O3.8F0.2 Li+1[ Ni2+0.5Mn4+1.5]O4        Li+1-2x[ Ni2+0.5-xNi4+xMn4+1.5]O4 + 2xLi+ + 2xe- → → C D X-rays 10µm Li 10µm Cu foil Al Case 25 µm Polyimide O-Ring ElectrolyteElectrode material  under investigation Current  Li2Mn2O4: SG I41/amd  Spinel crystal structures  LiMn2O4: SG Fd-3m  γ-MnO2 ↔ LiMn2O4 ↔ Li2Mn2O4 4V 3V (440) (224)tetr (531) (220)Al (440) (224)tetr (531) (220)Al (440) (531) (220)Al  Structural changes during discharge/charge processes (220)Al (224)tetr. (531)LNMO (440)LNMO Discharge 5.0 – 2.0 V tetr.+cub. phase 2 cub. phases cub. phase (224)tetr. (220)Al (531)LNMO (440)LNMO Charge 5.0 – 2.0 V Quantitative phase analysis Discharge 5.0 – 2.0 V Charge 2.0 – 5.0 V Charge 2.0 – 5.0 V (511)LNMO (220)Al (531)LNMO (440)LNMO (511)LNMO (224)tetr. 2 cub. phases tetr.+cub. phase cub. phase (220)Al (511)LNMO (440)LNMO (531)LNMO (220)Al (511)LNMO (440)LNMO (531)LNMO (224)tetr. (224)tetr. (220)Al (220)Al (220)Al (220)Al (220)Al (220)Al (531) (531) (531) (531) (531) (531) (440) (440) (440) (440) (440) (440) (224)tetr (224)tetr (511) (511) (511) (511) (511) (511) Instrumental resolution LNMO Y2O3 Y2O3 LNMO In situ cell Y2O3 Electrochemical Li (de)intercalation reaction: 1  2.7 V 2theta (°) 2  2.9 V 2theta (°) discharge charge 1 2 cub. tetr. Filenumber wt.-% V Electrochemical cell: 4.9V 4.7V 4.5V 3.2V 2.9V 4.7V 2.0V 4.4V 5.0V 4.9V 3.9V 3.0V 

In situ X-ray diffraction studies of Fe/F co-doped LiNi₀̣₅Mn₁̣₅O₄ spinel cathodes

https://publikationen.bibliothek.kit.edu/220088932/3816191

In situ X-ray diffraction studies of Fe/F co-doped LiNi₀̣₅Mn₁̣₅O₄ spinel cathodes

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