Vanadium Substitution in Li<sub>2</sub>MnSiO<sub>4</sub>/C as Positive Electrode for Li Ion Batteries

Wagner, Nils Peter; Vullum, Per Erik; Nord, Magnus; Svensson, Ann Mari; Vullum‐Bruer, Fride

doi:10.1021/acs.jpcc.6b01831

Cited by 21 publications

(6 citation statements)

References 52 publications

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“…Therefore, when the heavier Mn replaced by the lighter Ti, the corresponding peak intensity weakened. Similar phenomenon was observed in V substitution on the Mn site of Li 2 MnSiO 4 . Considering the above analysis, we can conclude that Ti ions have successfully incorporated into crystal structure and occupied Mn sites.…”

Section: Resultssupporting

confidence: 78%

“…When doping 20 mol% Ti (Figure S5), the capacity retention slightly decreases due to the increased Mn 2 SiO 4 impurity. [TiO 6 ] enriched Li 2 Mn 0.85 Ti 0.15 SiO 4 electrode exhibits remarkable initial Coulombic efficiency and capacity retention, which differs from the rapid capacity decay in previous reports ,,,,. After 8 th cycle, unexpected capacity loss occurs in Li 2 Mn 0.85 Ti 0.15 SiO 4 .…”

Section: Resultscontrasting

confidence: 66%

“…Figure a, b gives the CV curves of Li 2 MnSiO 4 and Li 2 Mn 0.85 Ti 0.15 SiO 4 electrodes at 1 st , 2 nd , 3 th cycle with a scan rate of 0.1 mV/s in 1.5‐4.8 V. As shown, the marked Peak 1,2 correspond to the redox potential of Mn ,. There are no Ti related peaks in Li 2 Mn 0.85 Ti 0.15 SiO 4 electrode, which further confirms that Ti ions are inactive in redox process.…”

Section: Resultsmentioning

confidence: 60%

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Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions

Zhao

Wei

et al. 2018

ChemistrySelect

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Li2MnSiO4 cathode material suffers from structural distortion caused by irreversible transition of [MnO4] tetrahedron to [MnO6] octahedron and layer exfoliation upon full delithiation, thus resulting in rapid capacity decay during cycling. In this study, Ti was introduced into the Mn site in Li2MnSiO4 as pillars to prevent the structural collapse. The results showed that [TiO4] tetrahedrons and [TiO6] octahedrons coexisted in Mn sites, and the proportion of [TiO6] octahedrons increased with increasing Ti. [TiOx] pillared Li2MnSiO4 samples presented greatly improved cycling stability, especially [TiO6] enriched Li2Mn0.85Ti0.15SiO4, which achieved the highest initial Coulumbic efficiency (86%) and the best capacity retention at C/20 rate. Moreover, Li2Mn0.85Ti0.15SiO4 exhibited excellent rate performance and retained 93% of initial discharge capacity after 50th cycles at C/2 rate. Ex‐situ XPS revealed [TiOx] pillars, especially [TiO6] pillars facilitated the reversible transition of [MnOx] during cycling. Ex‐situ XRD demonstrated better structure reversibility of [TiO6] enriched sample. The enhanced structural reversibility and cycling stability are ascribed to the pillaring effect of [TiOx], especially large [TiO6] octahedrons in structure, which ensure the reversible oxidation/reduction of Mn and alleviate the layer exfoliation during cycling.

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Section: Resultssupporting

confidence: 78%

Section: Resultscontrasting

confidence: 66%

Section: Resultsmentioning

confidence: 60%

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Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions

Zhao

Wei

et al. 2018

ChemistrySelect

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“…All experiments were carried out in a stainless‐steel ultrahigh vacuum (UHV) chamber with a base pressure of 2×10 −10 Torr. It was equipped with a PHI sputter gun for ion bombardment (sputtering) of the sample, an Omicron evaporator for deposition of Au, a solid‐state electrochemical cell for generation of S 2 gas, [30–32] OCI retarding field optics for Auger electron spectroscopy (AES), and an Omicron variable temperature STM. Details of the experiments are given in the Supplementary Information (SI).…”

Section: Methodsmentioning

confidence: 99%

Enhanced Nanostructure Dynamics on Au(111) with Adsorbed Sulfur due to Au−S Complex Formation

et al. 2021

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Chemisorbed species can enhance the fluxional dynamics of nanostructured metal surfaces which has implications for applications such as catalysis. Scanning tunneling microscopy studies at room temperature reveal that the presence of adsorbed sulfur (S) greatly enhances the decay rate of 2D Au islands in the vicinity of extended step edges on Au(111). This enhancement is already significant at S coverages, θS, of a few hundredths of a monolayer (ML), and is most pronounced for 0.1–0.3 ML where the decay rate is increased by a factor of around 30. For θS close to saturation at about 0.6 ML, sulfur induces pitting and reconstruction of the entire surface, and Au islands are stabilized. Enhanced coarsening at lower θS is attributed to the formation and diffusion across terraces of Au−S complexes, particularly AuS2 and Au4S4, with some lesser contribution from Au3S4. This picture is supported by density functional theory analysis of complex formation energies and diffusion barriers.

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“…The objective of this paper is to present a generic kinetics model for intergranular selective oxidation of binary alloys based on Wagner's theory for internal oxidation 11,12 , and our previous study on the boundary-function method 13 , oxidation kinetics 14,15 and heterogeneous reaction at the interface of two phases 16 . To model the penetration of oxidation along the grain boundary, transport processes taking place in the oxide, along the grain boundary, from bulk alloy to grain boundary, and reactions at the oxidation front itself must be considered in detail.…”

Section: Introductionmentioning

confidence: 99%

Modeling selective intergranular oxidation of binary alloys

Schreiber

et al. 2015

The Journal of Chemical Physics

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Intergranular attack of alloys under hydrothermal conditions is a complex problem that depends on metal and oxygen transport kinetics via solid-state and channel-like pathways to an advancing oxidation front. Experiments reveal very different rates of intergranular attack and minor element depletion distances ahead of the oxidation front for nickel-based binary alloys depending on the minor element. For example, a significant Cr depletion up to 9 μm ahead of grain boundary crack tips was documented for Ni-5Cr binary alloy, in contrast to relatively moderate Al depletion for Ni-5Al (∼100 s of nm). We present a mathematical kinetics model that adapts Wagner's model for thick film growth to intergranular attack of binary alloys. The transport coefficients of elements O, Ni, Cr, and Al in bulk alloys and along grain boundaries were estimated from the literature. For planar surface oxidation, a critical concentration of the minor element can be determined from the model where the oxide of minor element becomes dominant over the major element. This generic model for simple grain boundary oxidation can predict oxidation penetration velocities and minor element depletion distances ahead of the advancing front that are comparable to experimental data. The significant distance of depletion of Cr in Ni-5Cr in contrast to the localized Al depletion in Ni-5Al can be explained by the model due to the combination of the relatively faster diffusion of Cr along the grain boundary and slower diffusion in bulk grains, relative to Al.

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Vanadium Substitution in Li₂MnSiO₄/C as Positive Electrode for Li Ion Batteries

Abstract: Vanadium substitution is an interesting approach to manipulate the properties of the poor electronic and ionic conducting lithium transition metal orthosilicates. Especially, if incorporated on the Si-site it could alter the highly insulating character of the SiO 4 framework. This study

Cited by 21 publications

References 52 publications

Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions

Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions

Enhanced Nanostructure Dynamics on Au(111) with Adsorbed Sulfur due to Au−S Complex Formation

Modeling selective intergranular oxidation of binary alloys

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Vanadium Substitution in Li2MnSiO4/C as Positive Electrode for Li Ion Batteries

Abstract: Vanadium substitution is an interesting approach to manipulate the properties of the poor electronic and ionic conducting lithium transition metal orthosilicates. Especially, if incorporated on the Si-site it could alter the highly insulating character of the SiO 4 framework. This study

Cited by 21 publications

References 52 publications

Improved Structural Reversibility and Cycling Stability of Li2MnSiO4 Cathode Material by the Pillar Effect of [TiOx] Polyanions

Improved Structural Reversibility and Cycling Stability of Li2MnSiO4 Cathode Material by the Pillar Effect of [TiOx] Polyanions

Enhanced Nanostructure Dynamics on Au(111) with Adsorbed Sulfur due to Au−S Complex Formation

Modeling selective intergranular oxidation of binary alloys

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Vanadium Substitution in Li₂MnSiO₄/C as Positive Electrode for Li Ion Batteries

Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions

Improved Structural Reversibility and Cycling Stability of Li₂MnSiO₄ Cathode Material by the Pillar Effect of [TiO_x] Polyanions