TY  - JOUR
AU  - Niemöller, Arvid
AU  - Jakes, Peter
AU  - Eurich, Svitlana
AU  - Paulus, Anja
AU  - Kungl, Hans
AU  - Eichel, Rüdiger-A.
AU  - Granwehr, Josef
TI  - Monitoring local redox processes in LiNi 0.5 Mn 1.5 O 4 battery cathode material by in operando EPR spectroscopy
JO  - The journal of chemical physics
VL  - 148
IS  - 1
SN  - 1089-7690
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2018-00113
SP  - 014705 -
PY  - 2018
AB  - Despite the multitude of analytical methods available to characterize battery cathode materials, identifying the factors responsible for material aging is still challenging. We present the first investigation of transient redox processes in a spinel cathode during electrochemical cycling of a lithium ion battery by in operando electron paramagnetic resonance (EPR). The battery contains a LiNi0.5Mn1.5O4 (LNMO) spinel cathode, which is a material whose magnetic interactions are well understood. The evolution of the EPR signal in combination with electrochemical measurements shows the impact of Mn3+ on the Li+ motion inside the spinel. Moreover, state of charge dependent linewidth variations confirm the formation of a solid solution for slow cycling, which is taken over by mixed models of solid solution and two-phase formation for fast cycling due to kinetic restrictions and overpotentials. Long-term measurements for 480 h showed the stability of the investigated LNMO, but also small amounts of cathode degradation products became visible. The results point out how local, exchange mediated magnetic interactions in cathode materials are linked with battery performance and can be used for material characterization
LB  - PUB:(DE-HGF)16
C6  - pmid:29306293
UR  - <Go to ISI:>//WOS:000419394500029
DO  - DOI:10.1063/1.5008251
UR  - https://juser.fz-juelich.de/record/841812
ER  -