scholarly journals The early-stage growth and reversibility of Li electrodeposition in Br-rich electrolytes

2020 ◽  
Vol 118 (2) ◽  
pp. e2012071118
Author(s):  
Prayag Biswal ◽  
Atsu Kludze ◽  
Joshua Rodrigues ◽  
Yue Deng ◽  
Taylor Moon ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Early Stage ◽  
Solid Electrolyte Interphase ◽  
Growth Dynamics ◽  
Ion Diffusion ◽  
Reactive Metal ◽  
Metal Anode ◽  
Sem Image ◽  
Fine Control

The physiochemical nature of reactive metal electrodeposits during the early stages of electrodeposition is rarely studied but known to play an important role in determining the electrochemical stability and reversibility of electrochemical cells that utilize reactive metals as anodes. We investigated the early-stage growth dynamics and reversibility of electrodeposited lithium in liquid electrolytes infused with brominated additives. On the basis of equilibrium theories, we hypothesize that by regulating the surface energetics and surface ion/adatom transport characteristics of the interphases formed on Li, Br-rich electrolytes alter the morphology of early-stage Li electrodeposits; enabling late-stage control of growth and high electrode reversibility. A combination of scanning electron microscopy (SEM), image analysis, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and contact angle goniometry are employed to evaluate this hypothesis by examining the physical–chemical features of the material phases formed on Li. We report that it is possible to achieve fine control of the early-stage Li electrodeposit morphology through tuning of surface energetic and ion diffusion properties of interphases formed on Li. This control is shown further to translate to better control of Li electrodeposit morphology and high electrochemical reversibility during deep cycling of the Li metal anode. Our results show that understanding and eliminating morphological and chemical instabilities in the initial stages of Li electroplating via deliberately modifying energetics of the solid electrolyte interphase (SEI) is a feasible approach in realization of deeply cyclable reactive metal batteries.

Influence of VC and FEC Additives on Interphase Properties of Carbon in Li-Ion Cells Investigated by Combined EIS & EQCM-D

2020 ◽  
Author(s):  
Paul Kitz ◽  
Matthew Lacey ◽  
Petr Novák ◽  
Erik Berg
Keyword(s):  
Electrochemical Impedance ◽  
Solid Electrolyte Interphase ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Gas Analysis ◽  
Side Reactions ◽  
Ion Diffusion ◽  
Battery Cell ◽  
Anode Passivation ◽  
Order Of Magnitude ◽  
Li Ion

<div>The electrolyte additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are well known for increasing the lifetime of a Li-ion battery cell by supporting the formation of an effective solid electrolyte interphase (SEI) at the anode. In this study combined simultaneous electrochemical impedance spectroscopy (EIS) and <i>operando</i> electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) are employed together with <i>in situ</i> gas analysis (OEMS) to study the influence of VC and FEC on the passivation process and the interphase properties at carbon-based anodes. In small quantities both additives reduce the initial interphase mass loading by 30 to 50 %, but only VC also effectively prevents continuous side reactions and improves anode passivation significantly. VC and FEC are both reduced at potentials above 1 V vs. Li<sup>+</sup>/Li in the first cycle and change the SEI composition which causes an increase of the SEI shear storage modulus by over one order of magnitude in both cases. As a consequence, the ion diffusion coefficient and conductivity in the interphase is also significantly affected. While small quantities of VC in the initial electrolyte increase the SEI conductivity, FEC decomposition products hinder charge transport through the SEI and thus increase overall anode impedance significantly. </div>

scholarly journals Nanoscale Morphological Changes at Lithium Interface, Triggered by the Electrolyte Composition and Electrochemical Cycling

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Sebastian Mai ◽  
Janine Wessel ◽  
Anna Dimitrova ◽  
Michael Stich ◽  
Svetlozar Ivanov ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Morphological Changes ◽  
Solid Electrolyte Interphase ◽  
Electrolyte Composition ◽  
Morphological Properties ◽  
Tetraethylene Glycol ◽  
Lithium Nitrate ◽  
Simultaneous Application ◽  
Electrochemical Cycling

Understanding the electrochemical and morphological properties of the Li-electrolyte interface plays a central role in the implementation of metallic Li in safe and efficient electrochemical energy storage. The current study explores the influence of soluble polysulfides (PS) and lithium nitrate (LiNO3) on the characteristics of the solid electrolyte interphase (SEI) layer, formed spontaneously on the Li surface, prior to electrochemical cycling. Special attention is paid to the evolution of the electrochemical impedance and nanoscale morphology of the interface, influenced by the contact time and electrolyte composition. The basic tools applied in this investigation are electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM) performed at the nanoscale, and X-ray photoelectron spectroscopy (XPS). The individual addition of polysulfides and LiNO3 increases the interface resistance, while the simultaneous application of these components is beneficial, reducing the SEI resistive behavior. The electrochemical cycling of Li in nonmodified 1,2-dimethoxy ethane (DME) and tetraethylene glycol dimethyl ether (TEGDME) based electrolytes leads to slight morphological changes, compared to the pristine Li pattern. In contrast, we found that in the presence of PS and LiNO3, the interface displays a rough and inhomogeneous morphology.

Influence of VC and FEC Additives on Interphase Properties of Carbon in Li-Ion Cells Investigated by Combined EIS & EQCM-D

2020 ◽  
Author(s):  
Paul Kitz ◽  
Matthew Lacey ◽  
Petr Novák ◽  
Erik Berg
Keyword(s):  
Electrochemical Impedance ◽  
Solid Electrolyte Interphase ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Gas Analysis ◽  
Side Reactions ◽  
Ion Diffusion ◽  
Battery Cell ◽  
Anode Passivation ◽  
Order Of Magnitude ◽  
Li Ion

<div>The electrolyte additives vinylene carbonate (VC) and fluoroethylene carbonate (FEC) are well known for increasing the lifetime of a Li-ion battery cell by supporting the formation of an effective solid electrolyte interphase (SEI) at the anode. In this study combined simultaneous electrochemical impedance spectroscopy (EIS) and <i>operando</i> electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) are employed together with <i>in situ</i> gas analysis (OEMS) to study the influence of VC and FEC on the passivation process and the interphase properties at carbon-based anodes. In small quantities both additives reduce the initial interphase mass loading by 30 to 50 %, but only VC also effectively prevents continuous side reactions and improves anode passivation significantly. VC and FEC are both reduced at potentials above 1 V vs. Li<sup>+</sup>/Li in the first cycle and change the SEI composition which causes an increase of the SEI shear storage modulus by over one order of magnitude in both cases. As a consequence, the ion diffusion coefficient and conductivity in the interphase is also significantly affected. While small quantities of VC in the initial electrolyte increase the SEI conductivity, FEC decomposition products hinder charge transport through the SEI and thus increase overall anode impedance significantly. </div>

scholarly journals S-containing and Si-containing compounds as highly effective electrolyte additives for SiOx -based anodes/NCM 811 cathodes in lithium ion cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fuqiang An ◽  
Hongliang Zhao ◽  
Weinan Zhou ◽  
Yonghong Ma ◽  
Ping Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Electrochemical Impedance ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
High Energy ◽  
High Energy Density ◽  
Full Cell

Abstract Recently, high-energy density cells containing nickel-rich cathodes and silicon-based anodes have become a practical solution for increasing the driving range of electric vehicles. However, their long-term durability and storage performance is comparatively poor because of the unstable cathode-electrolyte-interphase (CEI) of the high-reactivity cathode and the continuous solid-electrolyte-interphase (SEI) growth. In this work, we study several electrolyte systems consisting of various additives, such as S-containing (1,3,2-dioxathiolane 2,2-dioxide (DTD), DTD + prop-1-ene-1,3-sultone (PES), methylene methanedisulfonate (MMDS)) and Si-containing (tris(trimethylsilyl) phosphate (TTSP) and tris(trimethylsilyl) borate (TMSB)) compounds, in comparison to the baseline electrolyte (BL = 1.0 M LiPF6 + 3:5:2 w-w:w EC: EMC: DEC + 0.5 wt% lithium difluoro(oxalato)borate (LiDFOB) + 2 wt% lithium bis(fluorosulfonyl)imide (LiFSI) + 2 wt% fluoroethylene carbonate (FEC) + 1 wt% 1,3-propane sultone (PS)). Generally, electrolytes with Si-containing additives, particularly BL + 0.5% TTSP, show a lower impedance increase in the full cell, better beginning-of-life (BOL) performance, less reversible capacity loss through long-term cycles and better storage at elevated temperatures than do electrolytes with S-containing additives. On the contrary, electrolytes with S-containing additives exhibit the advantage of low SEI impedance but yield a worse performance in the full cell than do those with Si-containing additives. The difference between two types of additives is attributed to the distinct function of the electrodes, which is characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS), which was performed on full cells and half cells with fresh and harvested electrodes.

scholarly journals Surface Structure Analysis of Initial High-Temperature Oxidation of SS441 Stainless Steel

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6136
Author(s):  
Tung-Yuan Yung ◽  
Hui-Ping Tseng ◽  
Wen-Feng Lu ◽  
Kun-Chao Tsai ◽  
Tien Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Early Stage ◽  
Treatment Temperature ◽  
Structural Variations ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
X Ray

Chromia-forming ferritic stainless steel (FSS) is a highly promising interconnect material for application in solid oxide fuel cells. In this study, initial oxidation of chromium oxides was performed at 500–800 °C to understand the evolution of materials at an early stage. The structural variations in oxide scales were analyzed through scanning electron microscopy, energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffractometry (XRD), laser confocal microscopy (LSCM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Surface electrochemical properties were investigated through electrochemical impedance spectroscopy to understand how the heat treatment temperature affected surface impedance. Treatment temperatures higher than 700 °C facilitate the diffusion of Cr and Mn, thus allowing ferritic spinels to form on the surface and leading to high electrical conductivity.

scholarly journals Spatiotemporally super-resolved dendrites nucleation and early-stage growth dynamics in Zinc-ion batteries

2021 ◽  
pp. 100420
Author(s):  
Xianqi Ye ◽  
Muhammad Saqib ◽  
Jiaxin Mao ◽  
Guopeng Li ◽  
Rui Hao
Keyword(s):  
Early Stage ◽  
Growth Dynamics ◽  
Zinc Ion

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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