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@INPROCEEDINGS{Roitzheim:905787,
      author       = {Roitzheim, Christoph and Finsterbusch, Martin and
                      Kaghazchi, Payam and Fattakhova-Rohlfing, Dina},
      title        = {{M}odified {C}athode {M}aterials for {G}arnet {B}ased
                      {A}ll-{S}olid-{S}tate {L}ithium {B}atteries},
      reportid     = {FZJ-2022-01010},
      year         = {2020},
      abstract     = {All solid-state batteries (ASB) are an emerging energy
                      storage technology, which is expected to improve the safety
                      on the cell level and to increase the battery energy
                      density. One of important issues in the development of
                      bulk-type ASBs with a high energy density is a possibility
                      of processing thick composites cathodes with percolating
                      pathways for ion and electron transport. For the ceramic
                      electrolytes such as garnet-type Ta-substituted LLZ
                      (Li6.6La3Zr1.6Ta0.4O12; LLZ:Ta) the practical realization of
                      composite cathodes is however challenging due to the
                      necessity of high temperature processing, raising the issues
                      of material compatibility and the formation of reaction
                      interphases influencing the total cell resistance. So far,
                      the thick garnet-based composite cathodes could be made only
                      with LiCoO2 (LCO) as an active material. For this kind of
                      ASB, high areal capacities of up to 1.63 mAh/cm² were
                      obtained. However, the utilization of high capacity cathode
                      materials like LiNixCoyMn1–x–yO2 (NCM) was so far not
                      possible due to the lower thermal stability of NCM as
                      compared to LCO and the resulting enhanced reactivity
                      between LLZ:Ta and NCM.Usually NCM materials were only
                      optimized for liquid electrolyte based batteries. Therefore,
                      an optimization of these active materials with respect to
                      their integration into ASBs is intended in this work.
                      Possible strategies for this optimization are doping or
                      substitution, surface coatings or core-shell structures.We
                      present the synthesis of optimized cathode materials for
                      bulk-type, fully inorganic ASBs based on ceramic materials.
                      A detailed material screening of NCM materials with
                      different compositions and modifications is performed by
                      evaluating the compatibility with cubic LLZ:Ta during
                      co-sintering at elevated temperatures. The compatibility is
                      tested by in situ high temperature X-ray diffraction
                      (HT-XRD), differential thermal analysis/thermogravimetry
                      (DTA/TG), Raman spectroscopy and X-ray photoelectron
                      spectroscopy (XPS). The experimental work is supported by
                      simulation studies using ab-initio-based approaches such as
                      density functional theory (DFT), ab initio molecular
                      dynamics (AIMD) as well as ab initio atomistic
                      thermodynamics and kinetics approaches. These simulation
                      based methods enable the prediction of lattice parameter of
                      NCM at different stages of charge. Additionally, the
                      calculation of interchange energies needed for the cation
                      interchange between NCM and cubic LLZ:Ta during co-sintering
                      is possible.Boron doping of NCM was investigated as a
                      possible strategy to improve its compatibility with LLZ:Ta,
                      as this strategy was demonstrated to be very efficient for
                      liquid electrolytes. The theoretical and experimental
                      results on B-doped NCM with different compositions are
                      already available. However, the formation of secondary
                      phases after co-sintering that was predicted by us
                      theoretically and confirmed experimentally using Rietveld
                      refinement discard boron doping as a way to enhance thermal
                      stability of NCM during the co-sintering with cubic LLZ:Ta.
                      Introduction of other dopants and surface coatings is
                      currently investigated to improve the compatibility of NCM
                      with cubic LLZ:Ta during co-sintering. The combined
                      experimental and theoretical approach is expected to result
                      in an optimized cathode material for ASBs with enhanced
                      performance.},
      month         = {Oct},
      date          = {2020-10-04},
      organization  = {ECS PRiME 2020, online (USA), 4 Oct
                       2020 - 9 Oct 2020},
      subtyp        = {Other},
      cin          = {IEK-1},
      cid          = {I:(DE-Juel1)IEK-1-20101013},
      pnm          = {1221 - Fundamentals and Materials (POF4-122) /
                      Verbundvorhaben SimCaMat: Modellierung und Synthese
                      verbesserter Kathodenmaterialien (03EK3054A)},
      pid          = {G:(DE-HGF)POF4-1221 / G:(BMBF)03EK3054A},
      typ          = {PUB:(DE-HGF)6},
      doi          = {10.1149/MA2020-025987mtgabs},
      url          = {https://juser.fz-juelich.de/record/905787},
}