bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the Chemical SEI of New and Aged Commercial Li Primary Batteries
Authors: Deichmann Eric J. , Cammack Claudina X. , Merrill Laura C. , Harrison Katharine , Rosenberg Samantha G. , Jungjohann Katherine L , Anderson Travis M. 
Published: December 2020

Li primary batteries have been used in commercial and military applications for decades due to their unrivaled energy density and long shelf-life. For years, the impressive shelf-life of these batteries has been primarily attributed to a stable solid electrolyte interphase (SEI), which hinders parasitic reactions at the anode/electrolyte interface. However, few published studies have probed electrode/electrolyte composition in commercial cells, and no previous studies have isolated contributions of the cathode and the electrolyte to SEI stability. To fill this knowledge gap, the present study attempts to de-convolute contributions from each entity by determining component compositions and unveiling the effect each constituent has on SEI stability. In this study, we investigate SEI compositions of three common Li primary chemistries - Li/MnO2, Li/FeS2 and Li/CFx, all of which display exceptional shelf-life. Additionally, due to the dynamic nature of the SEI, cells exposed to varying extents of ageing have been investigated to understand how the SEIs physical and chemical characteristics vary with time. Techniques such as X-ray Photoelectron Spectroscopy (XPS) and Energy-Dispersive Spectroscopy (EDS) are used to conduct chemical analysis of the SEI, while Scanning Electron Microscopy (SEM) is used to elucidate morphological changes in anode and SEI behavior as a function of extent of ageing and cathode/electrolyte chemistry.
This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories. Sandia National Laboratories is a multi-program laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
Fabrication and Characterization of Electrospun Pvam/TEOS Based Gel Polymer Electrolyte
Authors: Mentbayeva Almagul , Kassenova Nazym , Kalybekkyzy Sandugash , Bakenov Zhumabay , Kahraman Vezir 
Published: December 2020

Gel polymer electrolyte (GPE) is a promising alternative for the toxic and flammable liquid electrolyte in lithium ion batteries because of leak proof, longer shelf life and safety concerns. GPE consists of a porous polymer host and liquid electrolyte saturated within and combines the advantages of both the liquid and solid components [1].
In this study, a novel three-dimensional network GPE based on poly(vinyl alcohol)/maleic anhydride/tetraethyl orthosilicate (PVA/MA/TEOS) with polymer fibers were developed. Crosslinked nanofibrous polymer membranes for GPE of various composition were fabricated by UV-electrospinning method. The dual crosslink polymer membranes were obtained after heat treatment of as-prepared polymer nanofibers, due to the condensation of hydrolyzed TEOS. The morphology of the electrospun membranes was studied using scanning electron microscopy as shown in Figure 1. The uniform and well cross-linked nanofibers were formed with addition of 5 and 10% of TEOS.
The excellent thermal properties of the membranes were proven using thermal gravimetric analysis. The membranes have an improved porosity and exhibit high uptake when activated with the liquid electrolyte of lithium salt in a mixture of organic solvents, and also show high liquid retention properties. Electrochemical impedance spectroscopy and linear sweep voltammetry testes showed a high conductivity and vide range (up to 5.5 V) electrochemical stability of prepared GPE. Electrochemical performance of the polymer gel electrolyte is evaluated in Li/polymer electrolyte/LiFePO4coin cell with various current density and showed promising results.
Figure 1. SEM image of PVA/MA/TEOS fibers with (a) 5% and (b) 10% TEOS

Acknowledgements

This research was supported by Faculty-development competitive research grant “Development of composite anion exchange membranes with improved chemical and mechanical stability” from Nazarbayev University.

Reference
s:

[1] M. Zhu, J. Wu, Y. Wang, M. Song, L. Long, S.H. Siyal, X. Yang, G. Sui, Journal of Energy Chemistry 37 (2019) 126-142.

Figure 1
Nucleation, Growth, and Properties of the Solid Electrolyte Interphase – a Multimodal Approach Using a Model System
Authors: Cao Chuntian , Steinrück Hans-Georg , Borodin Oleg , Mars Julian Emanuel , Takacs Christopher J , Tsao Yuchi , Lukatskaya Maria R. , Schroeder Marshall , Xu Kang , Toney Michael F 
Published: December 2020

Due to the low potentials on anode materials in lithium-ion batteries, the electrolyte decomposes on the anode forming a passivation layer, termed solid electrolyte interphase (SEI). The SEI plays an essential role in battery performance since it is a major source of capacity loss and dictates cell kinetics. Nevertheless, the properties of the SEI are not yet well-understood.
Here, we present the utilization of a simple and well-defined model system to understand the atomic level SEI nucleation and growth, as well as structural and chemical properties. Experiments were performed in a half-cell configuration with N-doped silicon carbide (N-SiC) wafer working electrode, Li metal counter/reference electrode, and LP30 electrolyte (1M LiPF6 in 1:1 wt% ethylene carbonate:dimethyl carbonate). N-SiC has the advantage of being electrically conductive but electrochemically inactive, allowing for a straightforward interpretation of electrochemical and structural measurements, and provides information on the intrinsic electrolyte reactivity.
We used a multimodal approach combining in-situ X-ray reflectivity (XRR), precision electrochemistry at slow rates (e.g. 0.16 mV/s cyclic voltammetry), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). We obtained the evolution of the SEI’s thickness, electron density, and roughness through quantitative operando XRR measurements during the first two cyclic voltammetry (CV) cycles. Further, we found via complementary XPS experiment that the SEI was mainly composed of LiF, and we tracked the crystalline LiF growth with in-situ XRD. LiF can be formed via two reaction pathways. One is the direct reduction of PF6
-, the other is the electrocatalytic hydrogen evolution reaction of the trace amount of HF in the electrolyte, forming LiF and H2. In order to elucidate the formation mechanism of LiF, we combined the electrochemical and structural/chemical results for LP30 with precise electrochemistry using several baseline LiPF6 and/or HF containing electrolytes. The results indicate that the direct reduction of PF6
- contributes to LiF formed at ~ 1.5 V versus Li/Li+, consistent with our quantum chemistry calculations. Finally, we revealed that the ratio between organic and inorganic compounds in SEI could be tuned by changing the cycling rate.
We envision that this methodology and the use of well-defined model systems can be applied to other electrolyte-electrode systems. Our results are essential in understanding the formation mechanism and properties of SEI and can aid future experimental and computational works.
Quantifying Immobile Lithium at the Graphite Anode Surface from Formation to Fast Charging
Authors: Chebuske Matthew , Higashiya Seiichiro , Flottman Spencer , Bakhru Hassaram , Antonopoulos Konstantinos Byron , Paschos Odysseas , Gittleson Forrest S , Efstathiadis Harry 
Published: December 2020

Engineering the solid electrolyte interphase (SEI) at the surface of graphite anodes in Li-ion batteries is crucial to optimizing the rate capability, cycle life, and calendar life of commercial cells. It has been reported that fast-forming SEIs on composite graphite electrodes in a high-potential region (~0.24 V vs. Li/Li+) has a positive influence on rate capability in half cell formats [1]. Potentiostatic EIS modulation applied during formation has shown similar results to the fast formation method. In this work, we evaluated the efficacy of various SEI formation methods on the rate and cycle life of full cell Li-ion batteries, and then analyzed electrode surfaces ex situ to locate and quantify immobile lithium. Lithium nuclear reaction analysis (Li-NRA) provided an effective non-destructive method to correlate irreversible electrochemistry with physical surface phenomena [2].
It is well established that high current charging can induce Li plating on the graphite anode, leading to accelerated capacity fade. Several methods have been used to quantify this phenomena including titration and secondary ion mass spectroscopy (SIMS). Here, we employ Li-NRA and a suite of complementary techniques (i.e. XPS and SIMS) to show how the amount of immobile Li and its depth profile varies with charge rate (up to 5C) and cycle number.
[1] B. K. Antonopoulos, C. Stock, F. Maglia, H. E. Hoster, Electrochim. Acta, 269 (2018), 331-339.
[2] A. Schulz, D. DeRosa, S. Higashiya, M. Rane-Fondacaro, H. Bakhru, P. Haldar, J. Energy Storage 14 (2017), 106-111. A. Schulz, D. DeRosa, S. Higashiya, M. Rane-Fondacaro, H. Bakhru, P. Haldar, J. Power Sources 360 (2017), 129-135.
(Invited) Influence of Salt Anion on the Electrochemical and Thermal Stability of Electrolyte
Authors: Xing Lidan , Li Weishan 
Published: December 2020

Electrolytes for Lithium ion batteries mainly consist carbonate solvents and lithium salt. It has been well known that the species and component of solvents greatly affect the stability of electrolyte. While the role of salt anion in electrolyte stability has been neglected. In this presentation, we will reveal the influence of salt anion, mainly PF6
-, on the electrochemical stability and thermal stability of electrolyte. Specifically, on the anode surface, PF6
- shows great influence on the reduction stability and passivation capability of the induced solid electrolyte interphase (SEI) film; on the cathode surface, especially at high voltage, PF6
- affects the oxidation stability of solvent. Moreover, co-oxidation of PF6
- would generate HF. On the other hand, PF6
- reduces the thermal stability of the carbonate-based electrolyte, which would be significantly exacerbated when there are transition metal ions dissolved from cathode in the electrolyte. This overlooked effect is mainly due to the high catalytic effect of transition metal ions on the thermal decomposition of PF6
- to produce PF5. Understanding the mechanisms of the effect of salt anion on the stability of the electrolyte would provide a strong theoretical guidance for the design and development of the next generation lithium-ion battery electrolyte.
References:
[1]. Cun Wang, Lidan Xing, Jenel Vatamanu, Zhi Chen, Guangyuan Lan, Weishan Li, Kang Xu, Overlooked electrolyte destabilization by manganese (II) in lithium-ion batteries, Nat. Commun., 2019, 10,3423.
[2]. Kang Wang, Lidan Xing, Kang Xu, Hebing Zhou, Weishan Li, Understanding and Suppressing the Destructive Cobalt (Ⅱ) Species in Graphite Interphase, ACS Appl. Mater. Interfaces 2019,11,31490-31498.
[3]. Lidan Xing, Xiongwen Zheng, Marshall Schroeder, Judith Alvarado, Arthur von Wald Cresce, Kang Xu, Qianshu Li, and Weishan Li, Deciphering the Ethylene Carbonate–Propylene Carbonate Mystery in Li-Ion Batteries, Acc. Chem. Res., 2018,51, 282–289
[4]. Huozhen Zhi, Lidan Xing, Xiongwen Zheng, Kang Xu, Weishan Li, Understanding How Nitriles Stabilize Electrolyte/Electrode Interface at High Voltage, J. Phys. Chem. Lett. 2017, 8, 6048-6052.
[5]. Lidan Xing，Oleg Borodin, Grant Smith, Weishan, Li, A Density Function Theory Study of the Role of Anions on the Oxidative Decomposition Reaction of Propylene Carbonate, J. Phys. Chem. A. 2011,115, 13896-13905.
In Situ Growth Characterization of Electrodeposited Metal Contacts
Authors: Missault Nathan , Schwarzacher Walther 
Published: December 2020

We have developed a new electrochemical method to study the morphology of electrodeposited metal in-situ at the nano-scale , without the need of any additional surface characterization techniques.
A metal-insulator-metal (MIM) pillar structure with exposed edges is fabricated and subsequently contacted in a customize 4-electrode electrochemical cell.
The current is measured during electrodeposition while a voltage bias is applied between the two working electrodes, separated by a 50 nm thin dielectric. For appropriate choices of the voltage bias and deposition potential, the current between the two working electrodes can easily be distinguished from the electrodeposition current. This current represents the tunnelling current and eventually the mesoscopic contact current. The change in conductance of the MIM structure during electrodeposition is highly indicative of the growth mode of the electrodeposited metal. A rough film growth leads to step-like, quantized current transients typical of mesoscopic point contacts. Some steps correspond to the conductance quantum but smaller steps in the tunnelling current are also observed [1]. In contrast, a uniformly growing film leads to smooth, exponential current transients due to the significant contribution of a tunnelling current before physical contact is made.
We use this method to investigate the growth of Au thin films from a thiosulfate-sulfite bath, and the growth of Cu from a sulfate bath. We also show the effect of common levelling additives for Cu electrodeposition, such as polyethylene glycol (PEG) and benzotriazole (BTA).
Additionally, we have observed a significant dependence of the film growth on the voltage bias applied between the top and bottom metals of the MIM that is independent of the deposition potential.
This technique provides a novel platform to study the effect of additives and other electrodeposition variables in a wide range of electrolytes. Furthermore, it provides an efficient platform to fabricate nanogap structures.
[1] Li, C. Z., H. X. He, and N. J. Tao. "Quantized tunneling current in the metallic nanogaps formed by electrodeposition and etching." Applied Physics Letters 77.24 (2000): 3995-3997.
PEMFC Model Parameterization By Means of Differential Cell Polarization and Electrochemical Impedance Spectroscopy
Authors: Gerling Christophe , Hanauer Matthias , Berner Ulrich , Friedrich K. Andreas K 
Published: December 2020

Understanding the contributions of the loss mechanisms in PEM fuel cells remains a key issue for the optimization of the membrane electrode assembly (MEA) with respect to performance and ageing.
A full parameterization of all the physics via adapted experiments is considered as too challenging and/or too expensive, thus the parameters of performance models are often only estimated or fitted to insufficient experimental data from single cell steady-state measurements. In this study, we aim to remedy this issue by combining polarization and impedance measurements over a wide range of operating conditions on a differential cell setup with 12 cm2 and a straight channels flowfield. For this purpose, a fuel cell test station is entirely automated and allows therefore to design a full factorial experiment with relative humidity, temperature, oxygen partial pressure and current density as parameters, leading to more than 1000 operating points. Self-developed Matlab-tools enable the analysis of the impedance spectra by fitting them to equivalent circuit models (ECM) and thus to understand the impact of the operating conditions on the cell parameters, cf. Fig. 1. This step is supported by the evaluation of the distribution of relaxation times (DRT) for well-chosen conditions.
Since it is commonly known that the main contribution to the overall performance loss at low and medium current densities originates from the sluggish oxygen reduction reaction (ORR) on the platinum catalyst of the cathode and that there is still no consensus in literature concerning its proper modeling and parameterization for a full cell, this study focuses on this very mechanism. In order to get a proper parameterization, the measurements are corrected by the anode contribution, the impact of hydrogen crossover through the membrane and by the ohmic resistance as well as the protonic resistance.

Figure 1
A Comparative Analysis of PEM and Alkaline Water Electrolyzers
Authors: Millet Pierre , Abdelmotagali Ali , Assaud Loïc , El Rouby Waleed 
Published: December 2020

There are two main industrial techniques of water electrolysis operating under near-ambient temperature and pressure conditions: alkaline water electrolysis which uses a liquid electrolyte based on an aqueous solution of potassium hydroxide [1] and PEM water electrolysis [2] which uses a solid electrolyte made of a proton-conducting polymer. Both technologies present a set of strengths and weaknesses in view of practical application in the industry sector. The objective of this communication is to highlight the differences and similarities in terms of design (cell and stack) and balance-of-plant, and to present in a critical way what are these advantages and disadvantages, from a scientific viewpoint (that of materials science, especially for the selection of electrocatalysts), from a technological viewpoint (stack design and balance-of-plant) and from an economic viewpoint (comparative analysis of capex and opex). The discussion will take into account the situation which prevails on machines at the MW-scale. Particular attention will be paid to the ability of these machines to operate under transient conditions, in particular with a view to providing services to the electricity network. Several performance indicators such as the flexibility and reactivity of machines to the demands of network operators will be used to carry out this comparison. A detailed analysis of the existing limitations will make it possible to define a set of development perspectives highlighting possible complementarities.
[1] N. Guillet and P. Millet, in : Hydrogen Production: by Water Electrolysis’, chapter 4, Alkaline
Water electrolysis, A. Godula-Jopek, D. Stolten Editors, Wiley-VCH (2015).
[2] D. Bessarabov and P. Millet in: PEM water electrolysis, “Hydrogen and Fuel Cells Primers”, B.G. Pollet Editor, 1st Edition, Elsevier (2018).
Charge Transfer and Recombination Processes at p-CuBi2O4 Photoelectrodes
Authors: Oskam Gerko , Rodriguez Gutierrez Ingrid , Vega Alberto , Rodríguez Pérez Manuel , Coria Quiñones Sayda Dinorah , Jiménez Sandoval Omar , Rodriguez Gattorno Geonel 
Published: December 2020

Photoelectrochemical water splitting is an attractive method to convert solar energy to storable chemical energy in the form of hydrogen, however, the materials requirements to achieve this efficiently are challenging: the semiconducting material needs to absorb sunlight efficiently, must to be capable of reducing and/or oxidizing water, and has to be stable under illumination under current flow in an aqueous electrolyte solution. In particular, for small bandgap semiconductors, stability is often an issue, and it is difficult to fully avoid degradation of the material. In addition, the water reduction and oxidation processes need to occur fast, in order to favorably compete with recombination or surface degradation processes; hence, the kinetic rate constants for charge transfer and surface recombination are very important parameters. Intensity-modulated photocurrent spectroscopy (IMPS) is a powerful technique to study the carrier dynamics in a photoelectrochemical cell. The photocurrent admittance corresponds to the frequency-dependent external quantum efficiency, and time constants for charge transfer and surface recombination can be determined, provided a simple model can be applied.1

In this presentation, we focus on the dynamic properties of p-CuBi2O4 in order to elucidate the rate determining steps that determine the efficiency of photocathodic reactions. In inert aqueous solutions at pH 5, an unfavorable balance exists between the rate constants for charge transfer and surface recombination, which limits the conversion efficiency.2 On the other hand, upon adding H2O2 as an electron acceptor, the photoelectron transfer efficiency is improved related to faster electron transfer to the solution or slower surface recombination due to passivation effects. Strategies to improve the applicability of CuBi2O4 in solar water splitting systems are discussed.
The authors gratefully acknowledge CONACYT, SENER and CICY for funding through the Renewable Energy Laboratory of South East Mexico (LENERSE; Project 254667; SP-4), and CONACYT under the Basic Sciences (CB) project A1-S-28734.

References

“Photoelectrochemical Water Splitting at Semiconductor Electrodes: Fundamental Problems and New Perspectives”. L. M. Peter and K. G. Upul Wijayantha, ChemPhysChem, 15, 1983–1995 (2014).

“Charge Transfer and Recombination Dynamics at Inkjet-Printed CuBi2O4 Electrodes for Photoelectrochemical Water Splitting”. Ingrid Rodríguez-Gutiérrez, Rodrigo García-Rodríguez, Manuel Rodríguez-Pérez, Alberto Vega-Poot, Geonel Rodríguez Gattorno, Bruce A. Parkinson, and Gerko Oskam. J. Phys. Chem. C, 122, 27169−27179 (2018).
In Situ Measurement of Local pH at Working Electrodes in Neutral pH Solutions By the Rotating Ring‐Disk Electrode Technique
Authors: Yokoyama Yuko , Miyazaki Kohei , Kondo Yasuyuki , Miyahara Yuto , Fukutsuka Tomokazu , Abe Takeshi 
Published: December 2020

The pH is one of the most important factors for electrochemical reactions. The solution pH is often measured prior to the electrochemical measurements, but it is not sufficient to consider only bulk pH, especially for the measurements in neutral pH solutions. When electrochemical reactions occur that produce/consume protons or hydroxide ions, the local pH in the vicinity of an electrode becomes considerably different from the bulk pH. This local pH is important in considering electrodeposition and corrosion. Furthermore, it also has an critical effect on the operating voltage of aqueous batteries and capacitors, as local pH affects the electrochemical stability of water.1 However it is difficult to measure the local pH, because the measurements have to be made in a small region adjacent to the electrode. Herein, rotating ring-disk electrode (RRDE) is a promising tool for the local pH measurements, though it has not been applicable to neutral pH solutions.2 In this study, the theory of local pH measurements using RRDE was extended to apply to solutions over a wide pH range.3 This extended theory was corroborated by measurements of the local pH change during hydrogen oxidation/evolution reactions on platinum disk electrode in solutions with near-neutral pH. This reversible reaction makes it possible to control the local pH on the disk electrode by the applied potential. The platinum ring electrode successfully detected the local pH changes by potentiometry, and the measured local pH was in good agreement with the theoretical predictions (Fig. 1a). In addition, using the RRDE modified with iridium oxide (IrOx) ring, we were able to evaluate the dynamic changes in the local pH of the working electrodes during oxygen evolution reaction in Ar-saturated neutral-pH solution (Fig. 1b).4 Thus, RRDE with IrOx ring has the potential to be a widely applicable tool for measuring the local pH of the electrode during any electrochemical reactions.
Reference

Y. Yokoyama, T. Fukutsuka, K. Miyazaki, and T. Abe, J. Electrochem. Soc., 165, A3299–A3303 (2018).

W. J. Albery and A. R. Mount, J. Chem. Soc. Faraday Trans. 1, 85, 1181–1188 (1989).

Y. Yokoyama, K. Miyazaki, Y. Miyahara, T. Fukutsuka, and T. Abe, ChemElectroChem, 6, 4750–4756 (2019).

Y. Yokoyama, K. Miyazaki, Y. Kondo, Y. Miyahara, T. Fukutsuka, and T. Abe, Chem. Lett., 49, 195–198 (2020).

Figure 1