Bhaskar, A.

Dräger, C.

Ehrenberg, H.

Indris, S.

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz AssociationChristoph Dräger1, Sylvio Indris1, Aiswarya Bhaskar1, Helmut Ehrenberg11Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM-ESS), 76344 Eggenstein-Leopoldshafen, GermanyTitanium substituted LiCoTixMn1-xO4 (0.04≤x≤0.16):High-Voltage cathode materials for Li-Ion BatteriesMotivation• The specific capacity and operating potential of commonly used high-rate LiMn2O4 spinel cathode material is low which leads to an inferior energy density when combined in a LIB.• The operating potential and specific capacity of a Mn-based spinel can be raised by substituting Mn3+ with Co3+.• Substituting Mn4+ with Ti4+ could reduce the formation of Mn3+ and therefore could reduce the oxygen loss during cycling, which improves the structural stability of the active material.Summary and conclusions• Ti4+-substituted LiCoTixMn1-xO4 (0.04 ≤ x ≤ 0.16) can be successfully synthesized by a sol-gel method. • Electrochemical cycling reveals a reversible capacity above 5.0 V with and without Ti-substitution. No electrochemical activity regions corresponding to Ti are observed. • The LiCoTixMn1-xO4 (0.04 ≤ x ≤ 0.16) materials show a solid-solution mechanism of Li intercalation/deintercalation irrespective of the dopant amounts.MorphologyAcknowledgmentFinancial support from the Federal Ministry ofEducation and Research (BMBF) within theDESIREE project, grant no. 03SF0477B isgratefully acknowledged.Electrochemical investigationschargedischargeLiCoMnO4• Galvanostatic cycling against a Li-anode reveals a reversible discharge potential around 5.0 V with a spec. capacity of up to 100 mAh/g.• CV measurements reveal a polarization of 0.1 V.LiCoTi0.08Mn0.92O4Fd 3mC2/mLiCoMnO4• LiCoMnO4-based cathode materials were investigated via in situsynchrotron powder diffraction. All materials show the same solid-solution behavior during cycling.• The lattice parameters do not return to their initial state after one fullcycle and indicates irreversible changes in the spinel lattice which inturn leads to capacity losses.• Rietveld refinement results of the initial materials confirm the spinelphase (SG Fd 3m) as the main phase. Small amounts of impurity canbe identified as Li2MnO3 (SG: C2/m).Structural evolution during 1st cycle: In situ synchrotron powder diffraction7Li-MAS NMR7Li-MAS-NMR of LiCoMnO4 shows 2 separatedpeaks. After the charge process (delithitiation),the intensity of NMR-signal is drastically reducedand the peaks are slightly shifted.LiCoMnO4OxygenLithium/CobaltManganese/Cobalt

Titanium substituted LiCoTiₓMn₁₋ₓO₄ (0.04<=x<=0.16): High voltage cathode materials for Li-ion batteries

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz AssociationChristoph Dräger1, Sylvio Indris1, Aiswarya Bhaskar1, Helmut Ehrenberg11Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM), 76344 Eggenstein-Leopoldshafen, GermanyTitanium substituted LiCoTixMn1-xO4 (0.04≤x≤0.16):High-Voltage cathode materials for Li-Ion BatteriesMotivation• Batteries are essential for stationary as well as mobile energy storage applications.• Li-Ion Batteries offer high energy and power densities as well as good cycling stability.• The specific capacity and operating potential of commonly used high-rate LiMn2O4 spinel material is low which leads to an inferior energy density when combined in a LIB .• The operating potential of a Mn-based spinel can be raised by substituting Mn3+ with Co3+, which leads to a high energy density when combined in a Li-Ion Battery.Summary and conclusions• Ti4+-substituted LiCoTixMn1-xO4 (0.04 ≤ x ≤ 0.16) can be synthesized by a sol-gel method. • Electrochemical cycling reveals a reversible capacity above 5.0 V.• The LiCoTixMn1-xO4 materials show a solid-solution mechanism of Li intercalation/deintercalation irrespective of the dopant amounts.Morphology7Li-MAS NMRAcknowledgmentFinancial support from the Federal Ministry ofEducation and Research (BMBF) within theDESIREE project, grant no. 03SF0477B isgratefully acknowledged.Electrochemical investigations• Galvanostatic cycling against a Li-anode reveals a reversible discharge potential around 5.0 V with a spec. capacity of up to 100 mAh/g.• CV measurements reveal a polarization of 0.1 V.• LiCoMnO4-based cathode materials were investigated via in situsynchrotron powder diffraction. All materials show the same solid-solution behavior during cycling.• The lattice parameters do not return to their initial state after one fullcycle and indicates irreversible changes in the spinel lattice which inturn leads to capacity losses.• Rietveld refinement results of the initial materials confirm the spinelphase (SG Fd 3m) as the main phase. Small amounts of impurity canbe identified as Li2MnO3 (SG: C2/m).chargedischargeStructural evolution during 1st cycle: In situ synchrotron powder diffraction7Li-MAS-NMR of LiCoMnO4 shows 2 separatedpeaks. After the charge process (delithitiation),the intensity of NMR-signal is drastically reducedand the peaks are slightly shifted.2 q / °Fd 3mC2/mLiCoTi0.08Mn0.92O4LiCoTi0.04Mn0.96O4LiCoTi0.04Mn0.96O4LiCoMnO4LiCoMnO4Intensity/ a.u.LiCoMnO4LiCoMnO4

https://publikationen.bibliothek.kit.edu/220103785/3817010

Titanium substituted LiCoTiₓMn₁₋ₓO₄ (0.04<=x<=0.16): High voltage cathode materials for Li-ion batteries

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