TY  - JOUR
AU  - Beltrop, Kolja
AU  - Klein, Sven
AU  - Nölle, Roman
AU  - Wilken, Andrea
AU  - Lee, Juhyon J.
AU  - Köster, Thomas K.-J.
AU  - Reiter, Jakub
AU  - Tao, Liang
AU  - Liang, Chengdu
AU  - Winter, Martin
AU  - Qi, Xin
AU  - Placke, Tobias
TI  - Triphenylphosphine Oxide as Highly Effective Electrolyte Additive for Graphite/NMC811 Lithium Ion Cells
JO  - Chemistry of materials
VL  - 30
IS  - 8
SN  - 1520-5002
CY  - Washington, DC
PB  - American Chemical Society
M1  - FZJ-2018-04938
SP  - 2726 - 2741
PY  - 2018
AB  - Nickel-rich layered oxide materials (LiNixMnyCo1–x–yO2, x ≥ 0.8, LiNMC) attract great interest for application as positive electrode in lithium ion batteries (LIBs) due to high specific discharge capacities at moderate upper cutoff voltages below 4.4 V vs Li/Li+. However, the comparatively poor cycling stability as well as inferior safety characteristics prevent this material class from commercial application so far. Against this background, new electrolyte formulations including additives are a major prerequisite for a sufficient electrochemical performance of Ni-rich NMC materials. In this work, we introduce triphenylphosphine oxide (TPPO) as electrolyte additive for the application in graphite/LiNi0.8Mn0.1Co0.1O2 (NMC811) cells. The addition of only 0.5 wt % TPPO into a carbonate-based electrolyte (LiPF6 in EC:EMC) significantly increases the first cycle Coulombic efficiency as well as the reversible specific capacity and improves the capacity retention of the LIB full cell cycled between 2.8 and 4.3 V. Electrochemical results indicate that the full cell capacity fade is predominantly caused by active lithium loss at the negative electrode. In this contribution, X-ray photoelectron spectroscopy and inductively coupled plasma-mass spectrometry analysis confirm the participation of the electrolyte additive in the solid electrolyte interphase formation on the negative electrode as well as in the cathode electrolyte interphase formation on the positive electrode, thus, effectively reducing the active lithium loss during cycling. Furthermore, the performance of the TPPO additive is compared to literature known electrolyte additives including triphenylphosphine, vinylene carbonate, and diphenyl carbonate demonstrating the outstanding working ability of TPPO in graphite/NMC811 cells.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000431088400029
DO  - DOI:10.1021/acs.chemmater.8b00413
UR  - https://juser.fz-juelich.de/record/851243
ER  -