New insight into the mechanism of LiPO2F2 on the interface of high-voltage cathode LiNi0.5Mn1.5O4 with truncated octahedral structure

Zhao, Dongni; Song, Shengyuan; Ye, Xiushen; Wang, Peng; Wang, Jie; Wang, Yuan; Li, Chunlei; Mao, Liping; Zhang, Haiming; Li, Shiyou

doi:10.1016/j.apsusc.2019.06.146

Cited by 41 publications

(29 citation statements)

References 28 publications

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“…With the change of film-forming reaction, the composition of SEI includes more lithium fluoride components. [26] In the following cycle, the PO 2 F 2 À ions in electrolyte can continuously protects the interface of silicon material. Therefore, the high coulombic efficiency is obtained and electrochemical properties is improved during cycling.…”

Section: Resultsmentioning

confidence: 99%

“…[22,27] However, the LUMO of LiDFP with solvents is often higher than the pure solvents, such as the value in EC showing 5.01 eV than 1.43 eV. [24,26] It shows that this additive cannot be preferentially reduction to the LiPF 6 to form the SEI film. [28] Thus, many studies believed that such material had no obvious effect on the anode electrode.…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

“…In some studies, the LiDFP was used as a new additive to optimize the surface characteristics and improve the electrochemical performance for cathode electrode, [23,24] such as LiNi x Co y Mn z O 2 , LiNi 0.5 Mn 1.5 O 4 , specially it can enhances cyclic stability under high voltage window. [25,26] However, the LiDFP additive for increasing the ICE of Si-anode have not been found so far. In the experiment, different ratios of LiDFP (wt.0 %~4 %) is added in electrolyte to study the electrochemical performance.…”

Section: Introductionmentioning

confidence: 99%

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Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Zhu

Lao

et al. 2020

ChemElectroChem

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Silicon anodes usually endure low initial coulombic efficiency (ICE) in applications for lithium-ion batteries (LIBs), although the volume expansion and structural stability has been greatly improved under many efforts in the recent years. During the first charge and discharge, a large number of lithium ions can participate in the formation of a solid electrolyte interface (SEI) on anode surface, such as LiF, Li 2 CO 3 and many Li-based compounds, resulting in low efficiency, particularly as the nanosized silicon is widely applied to solve the volume effect. Herein, we find that the lithium difluorophosphate (LiPO 2 F 2 , LiDFP) additive shows some special properties, which greatly improve the reversible capacity in the first discharge. The silicon nanoparticles can deliver an ICE of 70.6 % with 2 wt% LiDFP in the electrolyte, which is increased by 17.7 % compared with the cell without LiDFP (ca. 52.9 %). By comparing the XPS and NMR results, it appears the LiDFP may reduce the number of lithium ions involved in the SEI reaction in the electrolyte during the first discharge, and thus the ICE can be improved.

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Section: Resultsmentioning

confidence: 99%

Section: Electrochemical Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Zhu

Lao

et al. 2020

ChemElectroChem

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“…We focus on these organic fragments, and omit inorganic CEI components like LiF and Li w P x O y F z , related to PF − 6 decomposition. Such inorganic species are present [12][13][14]40,41 but neither release CO 2 gas nor have been predicted to be oxidized at any reasonable voltages. Indeed, PF − 6 decomposition products have been suggested to partially passivate LNMO.…”

Section: Introductionmentioning

confidence: 99%

Anodic decomposition of surface films on high voltage spinel surfaces—Density function theory and experimental study

Leung

Rosy

Noked

2019

The Journal of Chemical Physics

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Oxidative decomposition of organic-solvent-based liquid electrolytes at cathode material interfaces has been identified as a main reason for rapid capacity fade in high-voltage lithium ion batteries. The evolution of "cathode electrolyte interphase" (CEI) films, partly or completely consisting of electrolyte decomposition products, has also recently been demonstrated to be correlated with battery cycling behavior at high potentials. Using Density Functional Theory (DFT) calculations, the hybrid PBE0 functional, and the (001) surfaces of spinel oxides as models, we examine these two interrelated processes. Consistent with previous calculations, ethylene carbonate (EC) solvent molecules are predicted to be readily oxidized on the LixMn2O4 (001) surface at modest operational voltages, forming adsorbed organic fragments. Further oxidative decompostion of such CEI fragments to release CO2 gas is however predicted to require higher voltages consistent with LixNi0.5Mn1.5O4 (LNMO) at smaller x values. We argue that multi-step reactions, involving first formation of CEI films and then further oxidization of CEI at higher potentials, are most relevant to capacity fade. Mechanisms associated with dissolution or oxidation of native Li2CO3 films, which is removed before the electrolyte is in contact with oxide surfaces, are also explored.

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“…found that LiPO 2 F 2 as the electrolyte can construct a stable and thin CEI film to improve the cyclic performance of cell at room temperature. The capacity retention of Li/LNMO cells with 1 wt % LiPO 2 F 2 improved from 85.76 to 95.92 % after 100 cycles [13] . Chen et al.…”

Section: Introductionmentioning

confidence: 98%

Improving the Cyclic Stability of LiNi_0.5Mn_1.5O₄ Cathode by Modifying the Interface Film with 8‐Hydroxyquinoline

et al. 2021

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Abstract8‐Hydroxyquinoline (8‐HDQN) is used as a bifunctional film‐forming additive to improve the capacity retention of Li/LiNi0.5Mn1.5O4 (LNMO) cell. Electrochemical analysis and ex‐situ analysis prove that 8‐HDQN can preferentially oxidize on the surface LNMO cathode to modify the Cathode Electrolyte Interface (CEI) film. The modified film effectively reduces the oxidation reaction of the electrolyte and the increase of polarization during the cycle. The CEI film derived from 8‐HDQN also inhibits the dissolution of transition metals ions from the LNMO electrode, and reduces the self‐discharge of the Li/ LNMO cell. Moreover, 8‐HDQN can also reduce the side reaction of PF5 by coordination with PF5 to improve the thermal stability of the electrolyte.

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New insight into the mechanism of LiPO2F2 on the interface of high-voltage cathode LiNi0.5Mn1.5O4 with truncated octahedral structure

Cited by 41 publications

References 28 publications

Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Anodic decomposition of surface films on high voltage spinel surfaces—Density function theory and experimental study

Improving the Cyclic Stability of LiNi_0.5Mn_1.5O₄ Cathode by Modifying the Interface Film with 8‐Hydroxyquinoline

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New insight into the mechanism of LiPO2F2 on the interface of high-voltage cathode LiNi0.5Mn1.5O4 with truncated octahedral structure

Cited by 41 publications

References 28 publications

Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Lithium Difluorophosphate as an Effective Additive for Improving the Initial Coulombic Efficiency of a Silicon Anode

Anodic decomposition of surface films on high voltage spinel surfaces—Density function theory and experimental study

Improving the Cyclic Stability of LiNi0.5Mn1.5O4 Cathode by Modifying the Interface Film with 8‐Hydroxyquinoline

Contact Info

Product

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Improving the Cyclic Stability of LiNi_0.5Mn_1.5O₄ Cathode by Modifying the Interface Film with 8‐Hydroxyquinoline