Electrolytes and interphases in Li-ion batteries and beyond.

Lithium metal batteries (LMBs) are among the most promising candidates of high-energy-density devices for advanced energy storage. However, the growth of dendrites greatly hinders the practical applications of LMBs in portable electronics and electric vehicles. Constructing stable and efficient solid electrolyte interphase (SEI) is among the most effective strategies to inhibit the dendrite growth and thus to achieve a superior cycling performance. In this review, the mechanisms of SEI formation and models of SEI structure are briefly summarized. The analysis methods to probe the surface chemistry, surface morphology, electrochemical property, dynamic characteristics of SEI layer are emphasized. The critical factors affecting the SEI formation, such as electrolyte component, temperature, current density, are comprehensively debated. The efficient methods to modify SEI layer with the introduction of new electrolyte system and additives, ex-situ-formed protective layer, as well as electrode design, are summarized. Although these works afford new insights into SEI research, robust and precise routes for SEI modification with well-designed structure, as well as understanding of the connection between structure and electrochemical performance, is still inadequate. A multidisciplinary approach is highly required to enable the formation of robust SEI for highly efficient energy storage systems.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.201500213

A Review of Solid Electrolyte Interphases on Lithium Metal Anode.

https://cyberleninka.org/article/n/591413.pdf

The state of understanding of the lithium-ion-battery graphite solid electrolyte interphase (SEI) and its relationship to formation cycling

Organic Carbonates as Solvents in Synthesis and Catalysis

The development of a stable, functional electrolyte is urgently required for fast-charging and high-voltage lithium-ion batteries as well as next-generation advanced batteries (e.g., Li–O2 systems). Acetonitrile (AN) solutions are one of the most promising electrolytes with remarkably high chemical and oxidative stability as well as high ionic conductivity, but its low stability against reduction is a critical problem that hinders its extensive applications. Herein, we report enhanced reductive stability of a superconcentrated AN solution (>4 mol dm–3). Applying it to a battery electrolyte, we demonstrate, for the first time, reversible lithium intercalation into a graphite electrode in a reduction-vulnerable AN solvent. Moreover, the reaction kinetics is much faster than in a currently used commercial electrolyte. First-principle calculations combined with spectroscopic analyses reveal that the peculiar reductive stability arises from modified frontier orbital characters unique to such superconcentrated ...

Unusual Stability of Acetonitrile-Based Superconcentrated Electrolytes for Fast-Charging Lithium-Ion Batteries

The formation of a passivation film (solid electrolyte interphase, SEI) at the surface of the negative electrode of full LiCoO2/graphite lithium-ion cells using LiPF6 (1M) in carbonate solvents as electrolyte was investigated by means of x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The analyses were carried out at different potentials of the first and the fifth cycles, showing the potentialdependent character of the surface-film species formation. These species were mainly identified as Li2CO3 up to 3.8 V and LiF up to 4.2 V. This study shows the formation of the SEI during charging and its partial dissolution during discharge. Copyright © 2005 John Wiley & Sons, Ltd.

Surface film formation on a graphite electrode in Li-ion batteries: AFM and XPS study

X-ray photoelectron valence spectra of lithium salts LiBF4, LiPF6, LiTFSI, and LiBETI have been recorded and analyzed by means of density functional theory (DFT) calculations, with good agreement between experimental and calculated spectra. The results of this study are used to characterize electrode/electrolyte interfaces of graphite negative electrodes in Li-ion batteries using organic carbonate electrolytes containing LiTFSI or LiBETI salts. By a combined X-ray photoelectron spectroscopy (XPS) core peaks/valence analysis, we identify the main constituents of the interface. Differences in the surface layers' composition can be evidenced, depending on whether LiTFSI or LiBETI is used as the lithium salt.

XPS Valence Characterization of Lithium Salts as a Tool to Study Electrode/Electrolyte Interfaces of Li-Ion Batteries

The solubility of carbon dioxide in γ-butyrolactone (BL), caprolactone (CL), propylene carbonate (PC), ethylene carbonate (EC), dimethylcarbonate (DMC), diethylcarbonate (DEC), and mixtures of thes...

Solubility of carbon dioxide in alkylcarbonates and lactones

Study of poly(3,4-ethylenedioxythiophene) films prepared in propylene carbonate solutions containing different lithium salts

Publisher Summary This chapter begins by considering the physiochemical properties of lithium as a metal anode. Lithium is the lightest metal of all elements of the periodic classification and has a very low density. It is by far the most energy-dense battery material. Primary (non-rechargeable) batteries make use of metallic lithium as anode and metal oxides like MnO2 and V2O5 as cathode. Commercial secondary lithium batteries (rechargeable) make use of carbon (graphite, coke, etc.) as anode material instead of metallic lithium. The growth of dendrites during the subsequent charge–discharge cycles will inevitably lead to short circuit or “dead” lithium deposition. Li-ion cells, electrolytes, lithium salts, and lithium hexafluorophospate are also considered in the chapter. LiPF6 as fluorinated lithium salt and its method of preparation are provided in detail. Transport properties of solutions of LiPF6 and other fluorinated lithium salts are also described. Viscosity is then dealt with in detail. Conductivity and electrochemical properties of electrolytes containing fluorinated lithium salts are also discussed.. PVDF is a fluoropolymer, which presents very interesting properties for use as a conductive membrane in Li batteries and as a binder for electrode materials. PVDF–HFP–SiO2 PEG system is also reviewed in the chapter.

F. Blanchard

Papers

Surface film formation on a graphite electrode in Li-ion batteries: AFM and XPS study

XPS Valence Characterization of Lithium Salts as a Tool to Study Electrode/Electrolyte Interfaces of Li-Ion Batteries

Solubility of carbon dioxide in alkylcarbonates and lactones

Study of poly(3,4-ethylenedioxythiophene) films prepared in propylene carbonate solutions containing different lithium salts

Physicochemical properties of fluorine-containing electrolytes for lithium batteries