Understanding the role of additive in the solvation structure and interfacial reactions on lithium metal anode

He, Xin; Zhang, Yujie; Wang, Kangli; Shan, Bin; Zhou, Min; Wang, Wei; Jiang, Kai

doi:10.1039/d2ta06084a

Cited by 9 publications

(4 citation statements)

References 68 publications

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“…The electron-deficient system in DFOB − enables a highly dispersed electron distribution, which induces electron transfer from Li + and NMP to DFOB − and further delivers a strong interaction between DFOB − and Li + −solvent complex. 29,31 Nuclear magnetic resonance (NMR) spectroscopy, subsequently, was applied to understand the changes in the local environment of Li + . As shown in Figure 1j, the 7 Li peaks gradually shift toward the downfield (more positive) after the replacement of 2.75 M LiTFSI by LiDFOB, induced by the strong electron-withdrawing effect of DFOB − .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…This difference further suggests that the incorporation of LiDFOB additive enables greater involvement of NMP molecules in solvation processes, thereby mitigating side reactions induced by free solvent molecules. The electron-deficient system in DFOB – enables a highly dispersed electron distribution, which induces electron transfer from Li + and NMP to DFOB – and further delivers a strong interaction between DFOB – and Li + –solvent complex. , …”

Section: Resultsmentioning

confidence: 99%

“…The modified solvation structures can also determine the electrochemical stability of bulk electrolytes and the interface . We can know that the free NMP molecule exhibits high HOMO energy from Figure d, which usually can trigger the generation of organic/inorganic (C–N/C–O, Li 2 CO 3 , Li 2 O) components during cycling .…”

Section: Resultsmentioning

confidence: 99%

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Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Li,

An,

Song

et al. 2023

J. Am. Chem. Soc.

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Owing to high ionic conductivity and mechanical strength, poly(vinylidene fluoride) (PVDF) electrolytes have attracted increasing attention for solid-state lithium batteries, but highly reactive residual solvents severely plague cycling stability. Herein, we report a free-solvent-capturing strategy triggered by reinforced ion–dipole interactions between Li+ and residual solvent molecules. Lithium difluoro(oxalato)borate (LiDFOB) salt additive with electron-withdrawing capability serves as a redistributor of the Li+ electropositive state, which offers more binding sites for residual solvents. Benefiting from the modified coordination environment, the kinetically stable anion-derived interphases are preferentially formed, effectively mitigating the interfacial side reactions between the electrodes and electrolytes. As a result, the assembled solid-state battery shows a lifetime of over 2000 cycles with an average Coulombic efficiency of 99.9% and capacity retention of 80%. Our discovery sheds fresh light on the targeted regulation of the reactive residual solvent to extend the cycle life of solid-state batteries.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Li,

An,

Song

et al. 2023

J. Am. Chem. Soc.

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show abstract

“…Lithium-metal anodes have attracted increasing interest due to their high specific capacity (3860 mAh g –1 ) and low redox potential (−3.040 V vs standard hydrogen electrode, SHE). − However, the growth of Li dendrites was accelerated in the violent reaction between the lithium anode and electrolyte under high voltages, leading to the thickening of lithium dendrites and low Coulombic efficiency (CE). In addition, a solid electrolyte interphase (SEI) shaped from Li metal reacting with the electrolyte and LiPF 6 cannot withstand the corrosion during the repeated charging/discharging process. , The unstable structure of SEI causes more side reactions between the Li anode and electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Multifunctional Electrolyte Additive for High-Nickel LiNi_0.8Co_0.1Mn_0.1O₂ Cathodes of Lithium-Metal Batteries

et al. 2023

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LiNi00.8Co0.1Mn0.1O2 (NCM811) is perceived as a promising cathode material in lithium-ion batteries for its high specific capacity and low cost. However, the catalytic surface between the cathode and electrolyte leads to intensive interfacial reactions and gas generation, ultimately causing rapid capacity fading and a great threat to the safety performance of the battery, which hinders its applications at high voltages. Herein, ethoxy(pentafluoro)cyclotriphosphazene (PFPN) as the electrolyte additive is applied to alleviate the above problems by constructing a solid electrolyte interphase on the cathode and anode. PFPN can be decomposed preferentially over basic electrolytes to shape the thin and stable interface film between the electrolyte and NCM811 cathode for restraining the production of gas and the corrosion of NCM811. The wettability of the separator can be enhanced by PFPN to promote uniform Li deposition. Also, PFPN has a flame-retardant effect due to its phosphoronitrile functional group. Moreover, the Li||Li symmetrical cells can achieve long-cycling stability with the PFPN-electrolyte (cycling performance of 800 h at 0.5 mA cm–2). Last, the capacity retention of NCM811||Li reaches 89.5% after 200 cycles at 1 C and 4.5 V.

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Interface Engineering Regulation by Improving Self‐Decomposition of Lithium Salt‐Type Additive using Ultrasound

Li,

Wang

et al. 2023

Adv Funct Materials

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Lithium salt‐type additives have triggered widespread concern because of their excellent film‐forming properties to construct a solid electrolyte interphase (SEI) with high stability and low impedance. However, little attention has been paid to enhancing the utilization efficiency of the expensive lithium salt‐type additives. Herein, the main factor limiting the decomposition of lithium difluoro bis(oxalate) phosphate (LiDFBOP) during the initial SEI formation is clarified. Combining the electrochemical analysis results and quantum chemistry calculations, it is inferred that LiDFBOP preferentially decomposes and generates soluble products accumulating on the graphite surface due to diffusion control kinetics. The excessive aggregation of these products on the electrode inhibits the subsequent continuous decomposition of LiDFBOP. An ultrasound auxiliary method is developed to accelerate the soluble product diffusion and promote the reduction decomposition of LiDFBOP increasing the inorganics content of Li2C2O4 and LiF in the formed SEI. Accordingly, the cell performance is greatly improved compared with that without ultrasound: Li/graphite cells with ultrasound can retain 60.60% of initial capacity after 500 cycles at 1C. This work not only pioneers the study of improving the utilization efficiency of additives contributing to reducing the electrolytes cost but also has direct guiding significance in the targeted regulation of interface properties.

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Understanding the role of additive in the solvation structure and interfacial reactions on lithium metal anode

Abstract: It is instructive to explain the action mechanism of additives as much as possible for the development of electrolyte. Recently, lithium disfluorobis (oxalato) phosphate (LiDFBOP) has been reported in Li-S...

Cited by 9 publications

References 68 publications

Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Multifunctional Electrolyte Additive for High-Nickel LiNi_0.8Co_0.1Mn_0.1O₂ Cathodes of Lithium-Metal Batteries

Interface Engineering Regulation by Improving Self‐Decomposition of Lithium Salt‐Type Additive using Ultrasound

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Understanding the role of additive in the solvation structure and interfacial reactions on lithium metal anode

Abstract: It is instructive to explain the action mechanism of additives as much as possible for the development of electrolyte. Recently, lithium disfluorobis (oxalato) phosphate (LiDFBOP) has been reported in Li-S...

Cited by 9 publications

References 68 publications

Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Ion–Dipole-Interaction-Induced Encapsulation of Free Residual Solvent for Long-Cycle Solid-State Lithium Metal Batteries

Multifunctional Electrolyte Additive for High-Nickel LiNi0.8Co0.1Mn0.1O2 Cathodes of Lithium-Metal Batteries

Interface Engineering Regulation by Improving Self‐Decomposition of Lithium Salt‐Type Additive using Ultrasound

Contact Info

Product

Resources

About

Multifunctional Electrolyte Additive for High-Nickel LiNi_0.8Co_0.1Mn_0.1O₂ Cathodes of Lithium-Metal Batteries