Understanding the spectroscopic signatures of Mn valence changes in the valence energy loss spectra of Li-Mn-Ni-O spinel oxides

Kinyanjui, Michael Kiarie; Axmann, Peter; Mancini, Marilena; Gabrielli, Giulio; Balasubramanian, Priyadharshini; Boucher, Florent; Wohlfahrt‐Mehrens, Margret; Kaiser, Ute

doi:10.1103/physrevmaterials.1.074402

Cited by 3 publications

(4 citation statements)

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“…This peak shift is in the same direction but 3 times larger than the energy shift observed and used to map lithium content in (Li)-FePO 4 . 19 Plasmon peak shifts have also been observed in other transition metal oxides (Li 1/2 Ni 0.5 Mn 1.5 O 4 22 and various manganese oxides 23 ) and indicate a change in electronic properties. An unidentified broad peak present at 10 eV, lying at a similar energy as an intraband transition observed in (Li)FePO 4 , 19 diminishes upon lithiation.…”

Section: ■ Results and Discussionmentioning

confidence: 79%

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM

Erichsen

Pfeiffer

Roddatis

et al. 2020

ACS Appl. Energy Mater.

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lithium manganese oxide spinel, tetragonal Li 2 Mn 2 O 4 , EELS, twinning, defects, interface, lithiation Spinel lithium manganese oxide (Li x Mn 2 O 4 ) is used as an active material in battery cathodes. It is a relatively inexpensive and environmentally friendly material, but suffers from capacity fade during use. The capacity losses are generally attributed to the formation of the tetragonal phase (x > 1) due to overpotentials at the surfaces of the micron-sized particles that are used in commercial electrodes. In this study, we investigate the mechanisms of tetragonal phase formation by performing electrochemical lithiation (discharging) in-situ in the transmission electron microscope (TEM) utilizing diffraction and high resolution as well as spectroscopy. We observe a sharp interface between the cubic spinel (x = 1) and the tetragonal phase (x = 2), that moves under lithium diffusion-control. The tetragonal phase forms as a complex nanotwinned microstructure, presumably to relieve the stresses due to expansion during lithiation. We propose 2 that the twinned microstructure stabilizes the tetragonal phase, adding to capacity loss upon deep discharge.

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Section: ■ Results and Discussionmentioning

confidence: 79%

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM

Erichsen

Pfeiffer

Roddatis

et al. 2020

ACS Appl. Energy Mater.

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“…The former is one of the most studied materials and is close to being industrially used as cathode material [ 5 ]. LiNi 0.5 Mn 1.5 O 4 is characterized by a theoretical capacity of 147 mAh g −1 due to reversible Ni 2+ /Ni 4+ redox, a two-stage voltage-composition plateau, indicating the occurrence of two two-phase transitions at an average potential of 4.75 V, and high rates of 3D Li + diffusion within the structure [ 6 , 7 , 8 , 9 , 10 , 11 ]. However, the use of a standard Li-ion electrolyte inevitably leads to the rapid degradation of LiNi 0.5 Mn 1.5 O 4 -based half- and full-cells.…”

Section: Introductionmentioning

confidence: 99%

Rational Screening of High-Voltage Electrolytes and Additives for Use in LiNi0.5Mn1.5O4-Based Li-Ion Batteries

et al. 2022

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In the present work, we focus onthe experimental screening of selected electrolytes, which have been reported earlier in different works, as a good choice for high-voltage Li-ion batteries. Twenty-four solutions were studied by means of their high-voltage stability in lithium half-cells with idle electrode (C+PVDF) and the LiNi0.5Mn1.5O4-based composite as a positive electrode. Some of the solutions were based on the standard 1 M LiPF6 in EC:DMC:DEC = 1:1:1 with/without additives, such as fluoroethylene carbonate, lithium bis(oxalate) borate and lithium difluoro(oxalate)borate. More concentrated solutions of LiPF6 in EC:DMC:DEC = 1:1:1 were also studied. In addition, the solutions of LiBF4 and LiPF6 in various solvents, such as sulfolane, adiponitrile and tris(trimethylsilyl) phosphate,atdifferent concentrations were investigated. A complex study, including cyclic voltammetry, galvanostatic cycling, impedance spectroscopy and ex situ PXRD and EDX, was applied for the first time to such a wide range of electrolytesto provide an objective assessment of the stability of the systems under study. We observed a better anodic stability, including a slower capacity fading during the cycling and lower charge transfer resistance, for the concentrated electrolytes and sulfolane-based solutions. Among the studied electrolytes, the concentrated LiPF6 in EC:DEC:DMC = 1:1:1 performed the best, since it provided both low SEI resistance and stability of the LiNi0.5Mn1.5O4 cathode material.

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“…This peak shift is in the same direction but three times larger than the energy shift observed and used to map lithium content in (Li)FePO 4 [208]. Plasmon peak shifts have also been observed in other transition metal oxides (Li 0.5 Ni 0.5 Mn 1.5 O 4 [206], various manganese oxides [229]) and indicated a change in electronic properties. An unidentified broad peak present at 10 eV, lying at a similar energy as an intraband transition observed in (Li)FePO4 [208], diminishes upon lithiation.…”

Section: Resultsmentioning

confidence: 56%

“…On the one hand, the peak in the region of about 10 eV decreases into a shoulder upon lithiation. This energy range is commonly attributed to intraband transitions [205,206] and changes are also observed in other lithium-containing energy materials (compare LiFePO 4 [207,208] or Li-Mn-Ni-Oxide spinels [206]). On the other hand, a shift and slight change of shape of the most probable energy loss, i.e.…”

Section: Comparison Of the Spectra Of Both Areasmentioning

confidence: 68%

In-situ lithiation of lithium manganese oxide in a transmission electron microscope

Erichsen¹

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Spinel lithium manganese oxide (Li x Mn 2 O 4 ) is used as an active material in battery cathodes. It is a relatively inexpensive and environmentally friendly material but suffers from capacity fade during use. The capacity losses are generally attributed to the formation of the tetragonal phase (x > 1) due to overpotentials at the surfaces of the micrometersized particles that are used in commercial electrodes. In this study, we investigate the mechanisms of tetragonal phase formation by performing electrochemical lithiation (discharging) in situ in the transmission electron microscope (TEM) utilizing diffraction and high resolution imaging as well as spectroscopy. We observe a sharp interface between the cubic spinel (x = 1) and the tetragonal phase (x = 2) that moves under lithium diffusion control. The tetragonal phase forms as a complex nanotwinned microstructure, presumably to relieve the stresses due to expansion during lithiation. We propose that the twinned microstructure stabilizes the tetragonal phase, adding to capacity loss upon deep discharge.

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Understanding the spectroscopic signatures of Mn valence changes in the valence energy loss spectra of Li-Mn-Ni-O spinel oxides

Cited by 3 publications

References 50 publications

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM

Rational Screening of High-Voltage Electrolytes and Additives for Use in LiNi0.5Mn1.5O4-Based Li-Ion Batteries

In-situ lithiation of lithium manganese oxide in a transmission electron microscope

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Understanding the spectroscopic signatures of Mn valence changes in the valence energy loss spectra of Li-Mn-Ni-O spinel oxides

Cited by 3 publications

References 50 publications

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn2O4 by In Situ TEM

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn2O4 by In Situ TEM

Rational Screening of High-Voltage Electrolytes and Additives for Use in LiNi0.5Mn1.5O4-Based Li-Ion Batteries

In-situ lithiation of lithium manganese oxide in a transmission electron microscope

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Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM

Tracking the Diffusion-Controlled Lithiation Reaction of LiMn₂O₄ by In Situ TEM