Overcoming Jahn-Teller Distortion for Spinel Mn Phase

Sun, Yang‐Kook; Jeon, Yong Jin; Leeb, Hwack Joo

doi:10.1149/1.1390942

Cited by 96 publications

(25 citation statements)

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“…Anion doping is considered an attractive strategy to improve the cycle stability and is adopted by many researchers to modify cathodes using anions such as F À [24], Cl À [25], Br À [26], S 2À [27], and PO 4 2À [28]. Among these anions, fluorine doping was found to enhance the performance of the cathode materials LiNi 1ÀxÀy Co x Mn y O 2 [29][30][31][32], lithium-rich cathodes such as Li 1.05 (Ni 0.5 Mn 0.5 ) 0.95 O 2 [33], olive LiFePO 4 [34], and spinel Li 4 Mn 5 O 12 [35].…”

Section: Introductionmentioning

confidence: 99%

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Xie

Liu

et al. 2015

Electrochimica Acta

131

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Section: Introductionmentioning

confidence: 99%

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Xie

Liu

et al. 2015

Electrochimica Acta

131

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“…Lithiation occurs reversibly as per the following reaction Li x Mn 2 O 4 þ DxLi þ þ Dxe À $ Li xþDx Mn 2 O 4 However, use of this material faces several challenges including somewhat limited rate capabilities, 8 dissolution of Mn 2þ ions into the electrolyte, 9,10 and a strong Jahn-Teller distortion at low potentials. [10][11][12] At low potentials the Mn 3þ /Mn 4þ redox couple produces Mn 3þ ions which may participate in the following disproportion reaction at the interface between the particle and the electrolyte 2Mn 3þ solid ! Mn 4þ solid þMn 2þ electrolyte At high degrees of lithiation, LiMn 2 O 4 will undergo a Jahn-Teller distortion that forces it from a cubic to tetragonal spinel structure as Li 2 Mn 2 O 4 is formed.…”

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confidence: 99%

“…Mn 4þ solid þMn 2þ electrolyte At high degrees of lithiation, LiMn 2 O 4 will undergo a Jahn-Teller distortion that forces it from a cubic to tetragonal spinel structure as Li 2 Mn 2 O 4 is formed. [10][11][12] Any regions of material in this tetragonal phase, most likely formed at the particle surface 11 near the end of a deep discharge, are no longer dimensionally compatible with neighboring cubic spinel material. 12 This can cause significant intraparticle defect formation which may ultimately lead to fracture.…”

mentioning

confidence: 99%

“…[10][11][12] Any regions of material in this tetragonal phase, most likely formed at the particle surface 11 near the end of a deep discharge, are no longer dimensionally compatible with neighboring cubic spinel material. 12 This can cause significant intraparticle defect formation which may ultimately lead to fracture. Fracturing has been detected in many LIB electrodes [13][14][15][16][17][18][19][20][21][22] and can cause a loss of cell capacity as damaged particles lose contact with their current collector or undergo non-reversible reactions at freshly exposed fracture surface area.…”

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confidence: 99%

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Evolution of Phase Transformation Behavior in Li(Mn1.5Ni0.5)O4 Cathodes Studied By In Situ XRD

Rhodes

Meisner

Kim

et al. 2011

J. Electrochem. Soc.

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In situ X-ray diffraction of Li(Mn 1.5 Ni 0.5 )O 4 was performed using a novel electrochemical cell based on coin cell hardware. The pristine material had a cubic spinel structure with a Ni 2þ oxidation state. As the cell was charged through its 4.75V plateau, a transition between spinels with Ni 2þ , Ni 3þ , and Ni 4þ oxidation was observed. As the oxidation of the nickel increased, the lattice parameter of the corresponding spinel diminished. During discharge, the spinel reversed its phase changes until only the Ni 2þ spinel was observed. As the discharge potential reached a plateau at 2.75V a tetragonal spinel phase was formed, which upon subsequent cell charging was completely converted back to a cubic spinel phase. Lattice parameter changes of each phase were calculated and showed a characteristic strain release during phase changes. After 15 full cycles the transition between cubic spinels was no longer complete and the formation of the tetragonal spinel phase was no longer detected. This suggests a gradual change from an ordered to disordered MNO structure and lithium trapping in the active material. These cycle-induced changes to phase transition behavior can be related to capacity fade and overall cell performance.A global demand for portable, high power energy storage systems has made the development of improved lithium ion batteries (LIBs) an important research priority. 1 Consumer electronics, electrical vehicles, power grid regulation, and remote sensing applications all stand to benefit from LIBs with higher power, greater capacity, and longer life. To achieve this goal the structural behavior of the active electrode materials must be well understood at multiple levels from lattice, to particle, to composite. How the structure changes as the material is reversibly intercalated or alloyed with lithium as well as how the structure evolves over the course of many lithiation/delithiation cycles are important considerations in the design, development, and selection of active materials.Among current cathode materials for lithium ion batteries those based on the LiMn 2 O 4 spinel structure are advantageous in their nontoxicity, low cost, and ease of preparation. 2-7 The spinel structure of this material offers a 3D diffusion pathway for lithium intercalation/ deintercalation. Lithiation occurs reversibly as per the following reactionHowever, use of this material faces several challenges including somewhat limited rate capabilities, 8 dissolution of Mn 2þ ions into the electrolyte, 9,10 and a strong Jahn-Teller distortion at low potentials. 10-12 At low potentials the Mn 3þ /Mn 4þ redox couple produces Mn 3þ ions which may participate in the following disproportion reaction at the interface between the particle and the electrolyte 2Mn 3þ solid ! Mn 4þ solid þMn 2þ electrolyte At high degrees of lithiation, LiMn 2 O 4 will undergo a Jahn-Teller distortion that forces it from a cubic to tetragonal spinel structure as Li 2 Mn 2 O 4 is formed. 10-12 Any regions of material in this tetragonal phase, most likely ...

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“…This type of behaviour would mirror the phase changes of Li x Mn 2 O 4 spinel. 34 It is therefore important to understand the factors affecting phase stability of the α and δ -V 2 O 5 polymorphs, ionic mobility in each phase and how mobility can be improved in a systematic way. Of particular interest is a strategy to stabilise the δ -Mg x V 2 O 5 phase at low x, retaining the improved ionic mobility of this phase over a broad range of x.…”

Section: Introductionmentioning

confidence: 99%

Phase stability of intercalated V₂O₅ battery cathodes elucidated through the Goldschmidt tolerance factor

McColl

Corà

2019

Phys. Chem. Chem. Phys.

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Orthorhombic V 2 O 5 is a promising Mg battery cathode material, and reversible intercalation in the layered α-phase has been claimed experimentally. However, these results, based on electrochemistry and XRD, are controversial. Previous computational studies have predicted high activation barriers (∼1 eV) for ionic migration in α-V 2 O 5 , although improved Mg 2+ mobility is expected in the δ -phase. Here, hybrid-exchange density functional theory is used to discuss structure, stability and intercalation in the α and δ phases, beginning with a model system with MV 2 O 5 stoichiometry, and varying ionic radius of the M cations. The relative stability of the two phases upon intercalation of M is rationalised through a tolerance factor-like behavioural trend, providing a framework for phase selection using intercalants of different ionic size. This tolerance factor behaviour is due to the presence of ferroelectrically distorted (2×2×2) perovskite blocks within the α-V 2 O 5 structure. The δ -phase is found to undergo a barrierless phase change to α in fully charged (de-intercalated) Mg x V 2 O 5 (x=0), indicating that stabilisation of δ -Mg x V 2 O 5 is required at low x if the δ phase is to be retained for higher Mg mobility. By employing dispersion interactions to accurately reproduce the interlayer distance, activation barriers for ion migration are found to be higher than reported in previous studies, clarifying questions regarding the extent of Mg intercalation that can be achieved experimentally. Interlayer ions are found to lower activation barriers for Mg 2+ mobility by up to ∼330 meV in the α phase by expanding the interlayer space. The results address open questions about the electrochemical performance of orthorhombic V 2 O 5 as Mg battery cathode material, and indicate atomic level mechanisms that activate ionic mobility in layered V 2 O 5 .One fundamental route to improving energy density is to move from sulphide to oxide based materials which have higher ionic character, thus providing higher voltages vs. Mg metal, whilst the lower atomic mass of O relative to S reduces weight. 7 However the very feature that enhances intercalation voltage, i.e. the stronger electrostatic interaction between the Mg ion and the anionic framework of the oxide cathode host, also increases acti-J o u r n a l N a me , [ y e a r ] , [ v o l . ] , 1-13 | 1 2 | 1-13 J o u r n a l N a me , [ y e a r ] , [ v o l . ] ,

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Overcoming Jahn-Teller Distortion for Spinel Mn Phase

Cited by 96 publications

References 0 publications

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Evolution of Phase Transformation Behavior in Li(Mn1.5Ni0.5)O4 Cathodes Studied By In Situ XRD

Phase stability of intercalated V₂O₅ battery cathodes elucidated through the Goldschmidt tolerance factor

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Overcoming Jahn-Teller Distortion for Spinel Mn Phase

Cited by 96 publications

References 0 publications

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Effects of fluorine doping on structure, surface chemistry, and electrochemical performance of LiNi0.8Co0.15Al0.05O2

Evolution of Phase Transformation Behavior in Li(Mn1.5Ni0.5)O4 Cathodes Studied By In Situ XRD

Phase stability of intercalated V2O5 battery cathodes elucidated through the Goldschmidt tolerance factor

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Phase stability of intercalated V₂O₅ battery cathodes elucidated through the Goldschmidt tolerance factor