bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoscale Ionic Materials for Nafion Based Nanocomposites Membranes As Single Lithium-Ion Conducting Polymer Electrolytes for Lithium Sulfur Batteries
Authors: Nicotera Isabella , Lufrano Ernestino , Simari Cataldo , Enotiadis Apostolos , Brutti Sergio , Nojabaee Maryam , Sievert Brigitta
Published: July 2022

Currently, rechargeable batteries with the lithium–sulfur (Li–S) chemistry has attracted great interest as one of the most promising candidates for next generation electrochemical energy storage systems. Research into these high energy density devices is critical to the development of thinner, lighter, and lower cost battery systems. One of the biggest obstacles for practical applications of Li-S batteries is caused by the soluble nature of the highly ordered lithium polysulfides (Li2Sn) in the organic electrolytes and induce a so-called “shuttle eﬀect”. A solid-state electrolyte (SPEs) could be a valid alternative in terms of reducing the polysulﬁdes dissolution and shuttle, as well as to protect the lithium metal anode and to minimize dendrite formation, which is beneﬁcial for improving the safety and cycle life of Li−S batteries. SPEs are typically dual-ion conductor systems both cations and anions are mobile and cause a concentration polarization leading to poor performances of batteries. Recently, single lithium-ion conducting solid polymer electrolytes (SLIC-SPEs) have been proposed for polymer electrolytes, where anions are covalently bonded to the polymer, inorganic backbone, or immobilized by anion acceptors and only the Li+ cation will contribute to a permanent flow of charge. They have advantages over conventional dual-ion conducting SPEs such as unity transference number, absence of harmful effect of anion polarization, extremely low rate of Li dendrite growth and immobilization of the lithium polysulfides in the lithium-sulfur (Li-S) batteries. Polymer electrolytes based on ionomers (e.g., Naﬁon) with easily ionizable groups (e.g., sulfonic groups covalently bonded to the polymer side-chains, −CF2SO3
−) are promising thanks to the high concentration of weakly coordinating anions (counterions). In this work, lithiated Naﬁon and Naﬁon-nanocomposites membranes based on Nanoscale Ionic Materials (NIMs) were synthesized, and their ionic conductivity and lithium transference number were investigated in common nonaqueous organic solvents (EC/PC and Glymes).

A thorough and systematic study of the lithium-ion transport was conducted by p 1H and 7Li pulsed ﬁeld gradient (PFG) NMR spectroscopy and electrochemical impedance spectroscopy (EIS), while the mechanical properties of the film electrolytes have been tested by dynamic mechanical analysis (DMA) in a wide temperature range. The electrochemical studies have been conducted both in Li/Li symmetric cell and in secondary Li-S cells. The preliminary results are very interesting, showing ionic conductivities of the order of 5 × 10-4 S/ cm at 25°C satisfactory properties in terms of stability window and stability of the lithium stripping. The lithium transport number is very close to unity thus confirming the complete immobilization of the negative charge carriers.
Computer Simulation of Amorphous Li3clo Solid Electrolyte and the Cathode-Electrolyte Interfaces
Authors: Ma Ying
Published: July 2022

Recently, Li3ClO based glasses with superionic properties have attracted wide attention as a promising solid electrolyte for all-solid-state batteries. These materials have a wide electrochemical window and have been reported to be stable with Li and Na metals. Nonetheless, theoretical studies have indicated that crystalline Li3OCl is not chemically or electrochemically stable, and the amorphous phase is slightly more unstable. To understand the origin of the experimentally observed electrochemical stability of Li3ClO glass, explicit cathode-electrolyte interfaces have been studied using ab initio molecular dynamics simulations. The structural patterns at different Li concentrations, corresponding to different Li chemical potential, have been revealed. Diffusion barriers across the interface have been calculated. These results provide atomistic insights regarding the interfacial structures and kinetics in lithium glass-based solid electrolytes.
Origins of the Fast-Charging Abilities of Niobium Containing Wadsley-Roth Phases
Authors: Baek Sun Woon , Wyckoff Kyra E. , Preefer Molleigh , Saber Muna , Van der Ven Anton , Seshadri Ram , Pilon Laurent
Published: July 2022

Lithium-ion batteries (LIBs) featuring high energy density have received particular attention in recent years due to their promise as electrical energy storage devices for electric vehicles and portable electronic devices. However, most of the commercial LIBs use graphite anode which suffer from the formation of solid-electrolyte interface (SEI) layer. Moreover, the poor performance of graphite anodes at high C-rates limits their application for fast-charging LIBs. To address the challenges associated with graphite anodes, niobium-containing Wadsley-Roth shear phase materials have been suggested. Thanks to the redox potential of Nb4+
(above 1 V versus Li/Li+), the niobium containing Wadsley-Roth shear phase materials avoid SEI formation. Furthermore, a combination of edge-shared and corner-shared octahedra in this type of shear phase materials forms many tunnel-like regions where Li-ions can rapidly diffuse during lithiation and delithiation. In fact, niobium-containing Wadsley-Roth shear phase materials show impressive cycling performance as fast-charging battery materials and maintain more than 50 % of their theoretical capacity at C-rate of 10 C.

This study aims to understand the fast-charging capability of niobium containing Wadsley-Roth shear phase materials accompanied by ion ordering in the application of LIBs. In addition, it aims to provide experimental evidence to elucidate the occurrence of Li-ion ordering in this type of shear phase materials. To do so, galvanostatic cycling and cyclic voltammetry were performed on selected niobium-containing Wadsley-Roth shear phase materials including TiNb2O7, PNb9O25, VNb9O25, and NaNb13O33. In addition, open circuit voltage and entropic potential of those materials were measured. The results show that ion ordering characterized by a tilde-shaped fluctuation in entropic potential was observed in all tested niobium containing Wadsley-Roth shear phase materials. Furthermore, the results indicate that the b-value approaching 0.5 corresponded to the first order transition accompanied by a two-phase coexistence while the b-value approaching 1 corresponded to the ordering of Li-ions. This analysis implies that the ion ordering phenomena can enhance the fast-charging capability of the material. This study provides valuable insights for fast-charging battery materials.
(Digital Presentation) Evaluating the Corrosivity of Liquid LiPF6 Electrolytes with Nickel-Coated Mild Steel Used in the Manufacturing of Li-Ion Cells for Energy Storage
Authors: Smith Scott R. , Sahota Preet , Wood Bryan D. , Way Brian
Published: July 2022

Effects of electrolyte degradation on cell performance and corrosion of cell components, e.g. current collectors, are topics that have been reported in the literature.1,2 Recently, it has been reported that water contamination of LiPF6 liquid electrolytes can lead to salt degradation, generating difluorophosphoric acid (DFPH) and hydrofluoric acid (HF).3 With strict quality control of the moisture content in individual components and the use of dryroom conditions for cell assembly the risk of moisture contamination can be practically eliminated. When moisture is allowed to enter the cell in controlled research samples, dark stains indicative of pitting type corrosion have been observed on the inside of mild steel cans that are used to house cylindrically wound electrodes (see Figure 1 inset). Motivation to understand the underlying corrosion mechanism and the influential factors is important to help lower the risk of occurrence in manufacturing further.

The use of a simple corrosion plate cell to study the susceptibility of a mild steel sample immersed in a LiPF6/EC/DMC (15/25/60 wt%) electrolyte will be discussed, with a focus on measured corrosion potentials, E
corr, and current densities, j
corr, extracted from the Tafel region of a potentiodynamic scan. Observations on the influence of acid degradation products in the electrolyte on the corrosion susceptibility of the mild steel will be discussed and applied to study select electrolyte additives previously reported in literature. Early results have shown that additives that scavenge HF and/or water directly can effectively suppress j
corr, as shown in Figure 1, whereas additives that increased DFPH generation had no apparent effect.

References:

[1] Myung, Hitoshi, and Sun. J. Mater. Chem., 2011, 21, 9891-9911.

[2] Ma et al. J. Phys. Chem. Lett. 2017, 8, 5, 1072–1077

[3] Wiemers-Meyer, Winter, and Nowak. Phys. Chem. Chem. Phys., 2016, 18, 26595-26601.

Figure 1: Bar graph of corrosion current, j
corr, measured for a LiPF6/EC/DMC (15/25/60 wt%) control electrolyte with 2500 ppm of water contamination, as well as with ~2 wt% of an additive that formed more DFPH than the control, an additive that formed more DFPH and HF than the control, and an additive that scavenged HF. Inset: Optical image of the inside of a mild steel can disassembled after 14 days of 60°C storage at top of charge illustrating dark regions indicative of steel corrosion.

Figure 1
Concentration Polarization in Batteries: Theory, Experimental Verification and Practical Relevance
Authors: Stolz Lukas , Winter Martin , Kasnatscheew Johannes
Published: July 2022

Apart from particle-type inorganic solid electrolytes, organic, i.e. solid polymer electrolytes (SPEs), are of high potential interest for the realization of next generation Li metal batteries, given their abundance, low cost, electrochemical stability and wetting ability.(1, 2)

Nevertheless, the poor ion transport in SPEs limits the battery operation to elevated temperature and/or lower rates only and remains main focus of R&D.(3) Besides the internal-resistance induced polarizations (overpotentials), it is the onset of concentration polarization, which determines the operation limit in terms of e.g. temperature and current density.

This work aims to practically unravel the mystery of concentration polarization by means of simple electrochemical experiments in Li||Li cells and mathematical descriptions via the well-known Sand and diffusion equations.(4, 5) The conformity of theory and experiments allows valuable mathematical determinations and predictions of parameter and operation limits. For example, these equations can predict the practical onset of concentration polarization. Also, parameter can be obtained, e.g. diffusion coefficients, based on the experimentally observed polarization onsets.

The relevance of concentration polarization including its impact on the cell performance even in high voltage LiNi0.6Mn0.2Co0.2O2 (NMC622)||Li cells is demonstrated by experimentally varying the applied current, the salt concentration, the temperature as well as the cell set-up (e.g. electrolyte thickness and electrode area-oversizing).(6) The validity of these relations is additionally confirmed in state-of-the-art liquid, i.e. LiPF6/carbonate-based, electrolytes and the special case of single-ion conducting electrolytes is discussed.

L. Stolz, S. Röser, G. Homann, M. Winter and J. Kasnatscheew, The Journal of Physical Chemistry C, 125, 18089 (2021).

J. Mindemark, M. J. Lacey, T. Bowden and D. Brandell, Prog. Polym. Sci., 81, 114 (2018).

J. Janek and W. G. Zeier, Nature Energy, 1, 16141 (2016).

L. Stolz, G. Homann, M. Winter and J. Kasnatscheew, Data in Brief, 34, 106688 (2021).

L. Stolz, G. Homann, M. Winter and J. Kasnatscheew, Materials Today, 44, 9 (2021).

L. Stolz, G. Homann, M. Winter and J. Kasnatscheew, ChemSusChem, 14, 2163 (2021).

Figure 1
Tetraglyme Based Electrolytes Enabled Excellent Cycling of Sodium Metal
Authors: LE Phung M-L , Jin Yan , Wang Chongmin , Engelhard Mark H. , Zhang Ji-Guang
Published: July 2022

Sodium metal is a promising anode for batteries because of its high theoretical specific capacity (1165 mAh g-1) and great abundance and low cost. However, fundamental issues such as dendrite formation, “dead sodium” accumulation during cycling, fast SEI dissolution or continuous SEI growth bring challenges for stabilizing reversibility of sodium metal anode. Recent advances in electrolyte engineering and development of highly stable cathode materials have enables sodium metal batteries reaching high CE (>99 %) at room temperature1-5.

Herein, we report a feasible pathway toward further stabilization of sodium metal anode using tetraglyme solvent (TEGDME) based electrolyte with various sodium salts (NaBF4, NaPF6, NaTFSI, NaFSI, NaClO4, NaOTf). It is demonstrated that a Na||Cu cell exhibited an average Coulombic efficiency of 99.9 % over 200, 850, and 1000 plating-stripping cycles when an electrolyte of 1M NaOTf in TEGDME, 1M NaPF6 in TEGDME, and 1M NaBF4 in TEGDME were used, respectively. Furthermore, 1M NaBF4 in TEGDME electrolyte also enabled excellent cycling stability of Na||Na3V2(PO4)2 batteries at high rate (1 C) for 1000 cycles with capacity retention of 90.8 %.

References

Seh, Z. W.; Sun, J.; Sun, Y.; Cui, Y. A Highly Reversible Room Temperature Sodium Metal Anode. ACS Cent. Sci. 2015, 1, 449−455.

Cao, R.; Mishra, K.; Li, X.; Qian, J.; Engelhard, M. H.; Bowden, M. E.; Han, K. S.; Mueller, K. T.; Henderson, W. A.; Zhang, J.-G. Enabling Room Temperature Sodium Metal Batteries. Nano Energy
2016, 30, 825−830.

Zheng, J.; Chen, S.; Zhao, W.; Song, J.; Engelhard, M.H.; Zhang, J.G. Extremely Stable Sodium Metal Batteries Enabled By Localized High-Concentration Electrolytes, ACS. Energy. Lett.
2018, 315−321.

Goktas, M.; Bolli, C.; Buchkheim, J.; Berg, E. J; Novak, P.; Bonilla, F.; Rojo, T.; Komaba, S.; Kubota, K.; Adelhem, P.; Stable and Unstable Diglyme-Based Electrolytes for Batteries With Sodium or Graphite as Electrode., ACS Appl. Mater. Interfaces
2019, 11, 32844-32855.

Le, P.M.L; Vo, D.T; Pan, H., Yan, J.; He, Y.; Cao, X.; Nguyen, H.V; Engelhard, M.H; Wang, C.; Xiao, J.; Zhang, J-G., Excellent Cycling Stability of Sodium Anode Enabled by a Stable Solid Electrolyte Interphase Formed in Ether-Based Electrolytes, Adv. Funct. Mater. 2020, 30, 2001151

Acknowledgement

This work is supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy (DOE) through the Advanced Battery Materials Research (BMR) program under contract no. DE-AC05-76RLO1830.
Effect of Particle Size on Thermodynamics and Lithium Ion Transport in Ti2Nb2O9 Electrodes Synthesized By Solid State or Sol-Gel Method
Authors: Zhou Yucheng , Le Calvez Etienne , Baek Sun Woong , Frajnkovič Matevž , Douard Camille , Crosnier Olivier , Brousse Thierry , Pilon Laurent
Published: July 2022

Ti2Nb2O9 has been identified as a promising lithium-ion battery anode material with large specific capacity, small cycling degradation, and good capacity retention at large currents. This study aims to gain insight into the charging mechanisms as well as the thermodynamics and ion transport in Ti2Nb2O9 synthesized by the solid state or the sol-gel method and formed by particles of different sizes using potentiometric entropy and operando isothermal calorimetric measurements. First, electrochemical testing showed that Ti2Nb2O9 electrodes made by sol-gel synthesis exhibited larger specific capacity, smaller polarization between lithiation/delithiation, and better capacity retention at large currents compared to those made by solid state synthesis. The measured open-circuit voltage and entropic potential revealed that the same solid solution charging mechanism prevailed and was independent of particle size, as confirmed by in situ XRD measurements. In other words, particle size had no influence on the quasi-equilibrium thermodynamics behavior of Ti2Nb2O9. However, Ti2Nb2O9 electrodes made by sol-gel synthesis featured smaller overpotential and faster lithium diffusion. In fact, operando isothermal calorimetry revealed smaller instantaneous heat generation rates and smaller time-averaged irreversible heat generation rates at Ti2Nb2O9 electrodes made by sol-gel synthesis compared to those made by solid state synthesis at any given C-rate. These observations highlight the smaller resistive losses and the larger electrical conductivity of Ti2Nb2O9 synthesized by the sol-gel method. Furthermore, time-averaged reversible heat generation rates at Ti2Nb2O9 electrodes made by both synthesis methods featured significant contributions from entropic changes, ion adsorption/desorption, and ion solvation/desolvation accompanied by ion-pairing.
High-Rate Electrochemical Lithium Cycling and Structure Evolution in Mo4O11
Authors: Vincent Rebecca , Luo Yunkai , Andrews Jessica , Zohar Arava , Zhou Yucheng , Mozur Eve , Cheetham Anthony K. , Pilon Laurent , Melot Brent C , Dunn Bruce S. , Seshadri Ram
Published: July 2022

Shear-phase early transition metal oxides, mostly of Nb, and comprising edge- and corner-shared metal–oxygen octahedra have seen a resurgence in recent years as fast-charging low-voltage electrodes for Li–ion batteries. Mo oxides, broadly, have been less well studied. Here we examine the reduced Mo oxide Mo4O11 that has a structure comprising only corner-connected MoO4 tetrahedra and MoO6 octahedra. Here we show that an electrode formed using micron sized particles of Mo4O11 as the active material can function as a high-rate Li–ion electrode against Li metal, with a stable capacity of over 200 mAh g-1 at the high rate of 5C. Operando X-ray diffraction (XRD), Raman spectroscopy, and entropic potential measurements are employed to understand the nature of charge storage. It is found that the structure dramatically changes upon the first lithiation, and subsequent cycling is completely reversible with low capacity fade. It is the newly formed, and potentially more layered structure that demonstrates high-rate cycling and small voltage polarization. This finding expands the scope of candidate high-rate electrode materials to those beyond the expected Nb-containing shear-phase oxide materials.

Figure 1
(Digital Presentation) Understanding the Impact of High-Nickel Cathode Microstructure on Battery Safety and Cycling Performance
Authors: Reid Hamish Thomas , Jervis Rhodri , Shearing Paul R
Published: July 2022

To meet the increasing energy demands of portable devices and electric vehicles, high-nickel lithium-ion cathode materials with the general formula Li(NixMnyCoz)O2 (NMC) have been extensively researched. Currently NMC811 is used commercially for high-energy applications. The energy density of NMC also comes with concerns over cycle life and safety1,2. To improve the cycle life of NMC-based cells, single-crystal materials have recently gained attention to tackle the particle cracking issues found in polycrystalline cathodes3. However, for successful introduction to the lithium-ion battery market, inherent safety over a material’s lifetime also needs to be proven. Failure and degradation mechanisms both need to be fully understood to improve the stability of future cathode materials. Abusive testing, such as overheating, overcharge and nail penetration, has been used in conjunction with in-situ and ex-situ X-ray computed tomography (CT) 3D imaging to perform post-mortem studies and understand the relationship between thermal failure and cathode microstructure4,5. However, the interplay between safety characteristics, microstructural properties and material degradation remains unclear.

This work first aims to compare the safety performance of polycrystalline and single-crystal NMC811 in 200 mAh pouch cells. Accelerating rate calorimetry (ARC) with a heat-wait-search (HWS) technique is used to heat cells and determine the onset of self-heating, onset of thermal runaway and the peak thermal runaway temperature. Laboratory-based pre- and post-mortem in-situ and ex-situ X-ray CT is also used for non-destructive imaging at multiple length scales to determine how failure propagates through the cells and the impacts on the electrodes and microstructure. Pouch cells containing polycrystalline and single-crystal NMC811 cathode and graphite anode are electrochemically cycled to induce material degradation. EIS measurements and diagnostic cycles are performed to identify prevalent degradation modes in both types of cathode materials. Finally, the same ARC and X-ray CT characterisations are performed on the aged cells to determine how degradation and changes to the material structure affect the safety performance in high-nickel cathode materials.

The results of this work will improve the current understanding of capacity fade in high-nickel cathodes and the safety behaviour over the lifetime of a battery cell. This information can then be used to inform future materials development and strategies for mitigating thermal runaway in batteries.

References

L. Ma, M. Nie, J. Xia, and J. R. Dahn, J. Power Sources, 327, 145–150 (2016).

H. J. Noh, S. Youn, C. S. Yoon, and Y. K. Sun, J. Power Sources, 233, 121–130 (2013).

J. Langdon and A. Manthiram, Energy Storage Mater., 37, 143–160 (2021).

D. Patel, J. B. Robinson, S. Ball, and D. J. L. Brett, (2020).

D. P. Finegan et al., Phys. Chem. Chem. Phys., 18, 30912–30919 (2016).
Effect of a Heterogeneous Distribution of the Conductive Additives and Binder Domain on the Impedances of Lithium-Ion Battery Electrodes
Authors: Prasad Mrudula , Hein Simon , Danner Timo , Latz Arnulf
Published: July 2022

The conductive carbon and binder are essential components of Lithium-ion battery electrodes. Their main task is to enhance the electrical connectivity and mechanical stability. Therefore, a homogeneous distribution of the carbon binder domain (CBD) throughout the electrode is desired. However, inhomogeneities can arise in the production process. At high drying rates of the wet coating, the CBD migrates to the surface of the electrode due to the drag of the evaporating solvent. This effect causes a gradient of the CBD through the thickness of the electrode. This process has two effects: (a) depletion of the CBD at the current collector, diminishing the electronic pathways and the adhesion of the electrode layer, and (b) accumulation of the CBD at the electrode surface, thus blocking pathways for Lithium transport. This is especially prominent in thick electrodes. Therefore, we investigate the effect of binder migration on the electrochemical performance of NMC622 electrodes of Lithium-ion batteries.

In our simulations we use virtual electrode microstructures of NMC622 electrodes which are informed by tomography data. As it is challenging to resolve the CBD using tomographic techniques, it is distributed on a model-basis at the contact points of active material particles using an in-house structure generator[1].

The valuable information derived from combining microstructure-resolved simulations with electrochemical impedance spectroscopy (EIS) on symmetric cells is used to characterize the Lithium-ion transport in the electrode pore space, including the contributions of the CBD. Additionally, half-cell discharge simulations are also conducted to analyze the effect of CBD heterogeneity on electrode performance.

Through our work, we demonstrate the significance of the CBD distribution and enable predictive simulations for future battery design.

[1] Hein S. et al, J. Electrochem. Soc. 2020, 167 013546

Figure 1
Reactive Spray Drying Approach Towards rGO As Matrix Material for the Cathode of Li-S Batteries
Authors: Müllner Sebastian , Roth Christina
Published: July 2022

Lithium-sulfur batteries represent a promising alternative to the classical Li-ion technology, particularly due to the high specific energy density combined with the good environmental sustainability of sulfur. Compared to state-of-the-art cathode materials for Li-ion batteries (LiB), which usually contain cobalt and/or manganese, sulfur is less toxic and much more abundant [1]. Additionally, the theoretical capacity of 1.675 mAh g-1 is more than eight times higher than typical cathode materials as Lithium-Nickel-Mangan-Cobalt-Oxide (NMC), Lithium-Cobalt-Oxide (LCO) or Lithium-Iron-Phosphate (LFP) [1,2]. One of the main challenges of sulfur is the so-called “shuttle effect” [1,3]. During lithiation soluble intermediates (polysulfides) migrate to the anode side, further react and precipitate, resulting in a continuous loss of active material and capacity. Next to that, the poor electrical conductivity (5∙10-30 S cm-1) does not allow the utilization of pure sulfur as cathode material [1].

To improve the low conductivity, carbon-containing composites have been proposed as cathode material for Li-S batteries for several decades. One possible carbon matrix material is reduced graphene oxide (rGO) [4]. The reduced form of partially oxidized graphite (graphite oxide; GO) is a graphene-like material with high potential for a scale-up to mass production.

In our group, we have developed a new synthesis method to rapidly reduce GO using a reactive spray drying technique, where most functional groups can be removed from GO within seconds. The rapid thermal processing leads to a reduced and exfoliated rGO, which still contains small amounts of epoxy groups within the carbon lattice. These remaining oxygen atoms influence the conjugated π-bonds of the graphene-like matrix and thus change the polarity of the surface. A thermal post-treatment for 2 h in Ar/H2 can further reduce the remaining functional groups leading to a highly non-polar surface.

It is assumed that oxygen-containing groups (e.g. epoxy and hydroxy) result in a varying adsorption behavior of the polysulfides, affecting the unwanted “shuttle effect” and thus influencing the electrochemical performance [5]. Here, we show the impact of remaining functional groups in rGO on the electrochemical performance of S-rGO composites as cathode material vs. Li/Li+. We compare untreated GO to reactive spray dried and additionally (thermally) post-treated rGO. Furthermore, we analyze the composites in terms of asymmetric and symmetric bonding vibrations as well as crystallinity using FT-IR, RAMAN and XRD.

[1] Baikalov, N. et al., Frontiers Energy Research
2020, 8, 207

[2] Su, Y.-S. et al., Nature Communications
2013, 4, 2985

[3] Ren, W. et al., Energy Storage Materials
2019, 23, 707-732

[4] Shastri, M. et al., Ceramics International
2021, 47, 10, B, 14790-14797

[5] Ji, L. et al., Journal of the American Chemical Society
2011, 133, 18522-18525
Enhancing Cycling Stability of NMC811 Li-Ion Batteries By Encapsulating with Nanomaterials
Authors: Khunrugsa Chirayu , Sawangphruk Montree
Published: July 2022

Li(Ni0.8Mn0.1Co0.1)O2 (NMC811) cathode material for Li-ion battery has been considered as a next-generation of the lithium-ion battery, used for advanced applications such as electric vehicles. Although it has a high specific capacity, the major drawbacks of this material result in the obstacle of commercialization. In this work, the composite materials of reduced graphene oxide (rGO), carbon black (CB), and titanium dioxide (TiO2) nanoparticles were coated on the surface of the NMC811 particle by mechano-fusion technique, forming the core@shell structure to protect the morphological instability, as well as the electrolyte decomposition. Also, the shell elevates the Li-ion diffusion and ionic conductivity. Moreover, we firstly reported the fined-tune step formation protocol of cylindrical cell type lithium-ion battery (18650). As a result, the core@shell cathode with the step formation of 3.0-4.0V CC-charge/CCCV-discharge condition can deliver the capacity retention over 90% after 400 cycles at 1C (3.0-4.2V).
5V Solid-State Lithium Batteries Using Garnet-Based Electrolytes and LiNi0.5Mn1.5O4 Spinel Cathode Composite
Authors: Niketic Svetlana , Filoso Gina , Houache Mohamed , Karkar Zouina , Yim Chae-Ho , Abu-Lebdeh Yaser
Published: July 2022

There is an ever increasing demand to increase the gravimetric and volumetric energy density of Lithium batteries as well as enhancing their safety cycle life and lower safety. Solid-State batteries (SSB) enjoy a great attention nowadays due to their potential to meet all those requirements and power the EV revolution. The use of solid electrolytes (SE) in commercial batteries has been solely limited to polymer electrolytes based on poly(ethylene oxide), PEO, coupled with LiFePO4 (LFP) that are limited by the oxidative stability of PEO to < 3.6 V and the low potential of LFP at 3.4 V. The commercial cells are cycled at high temperature (45 ⁰C) to overcome the modest ambient ionic conductivity of the SE and under a stack pressure and a cathode composite to overcome the high interfacial resistances of the solid-solid interfaces. A cathode composite is made of conventional cathode components with a "catholyte" added to the formulation. The catholyte is made of an optimized amount of an ionic conductor that is mostly derived from the solid electrolyte formulation. Very recent studies by our research group (1) and others (2) have shown that higher voltage cells can be made by using garnet or perovskite-based ceramic/polymer composites and LiNi0.5Mn0.3Co0.2O2 (NMC532) or LiNi0.6Mn0.2Co0.2O2 (NMC 622) layered cathodes reaching 4.2 V and can operate for few cycles. Herein, we extend the work in order to further increase the voltage of the SSB cells by using LiNi0.5Mn1.5O4 (LNMO) spinel cathode with its high potential of 4.7 V. The Tantalum-doped Lithium Lanthanum Zirconate, Li6.4La3Zr1.4Ta0.6O12 (Ta-doped LLZO, LLZTO), of the garnet family of solid electrolytes has been selected as a SE due to their high ambient ionic conductivity, wide electrochemical stability window and good chemical stability against Li metal. PEO and other compatible polymers have been used to formulate composite SEs in thin films and their properties were studied and compared with LLZTO pellets. Cells have been made using composite cathode formulations composed of LNMO cathode as an active material, carbon black, conventional and novel binders and a SE-based and proprietary catholyte coupled with the SE films or pellets and thick/thin Li films. The short-term cycling performance of the cells assembled with selected SEs and composite cathodes along with other electrochemical results will be presented.

References:

(1) Hilal Al-Salih, Allan Huang, Chae-Ho Yim, Annica I. Freytag, Gillian R. Goward, Elena Baranova and Yaser Abu-Lebdeh, 2020, J. Electrochem. Soc. 167 070557.

(2) P. López-Aranguren, X. Judez, M. Chakir, M. Armand and L. Buannic, 2020, J. Electrochem. Soc. 167 020548.
(Keynote) Solution-Phase Growth of Cu Microplates: A Multi-Scale Theoretical Analysis from First Principles
Authors: Fichthorn Kristen
Published: July 2022

We use first-principles density functional theory (DFT) to quantify the role of iodide in the solution-phase growth of Cu microplates. Our calculations show that a Cu adatom binds more strongly to hcp hollow sites than fcc hollow sites on iodine-covered Cu(111) – the basal facet of two-dimensional (2D) Cu plates. This feature promotes the formation of stacking faults during seed and plate growth which, in turn, promotes 2D growth. We also found that iodine adsorption leads to strong Cu atom binding and prohibitively slow diffusion of Cu atoms on Cu(100) – a feature that promotes Cu atom accumulation on the {100} facets of a growing 2D plate. Incorporating these DFT insights into analog experiments, in which we initiated the growth of Cu plates from small seeds consisting of magnetic spheres, we confirmed that two or more stacking faults are required for lateral plate growth, consistent with prior studies. Moreover, plates can take on a variety of shapes during growth: from triangular and truncated triangular to round and hexagonal – consistent with experiment. Using absorbing Markov chain calculations, we assessed the propensity for 2D vs. 3D kinetic growth of the plates. At experimental temperatures, we predict plates can grow to achieve lateral dimensions in the 1–5-micron range, as observed in experiments.
(Invited) Second-Layer Growth Kinetics As a Decisive Factor for Non-Equilibrium Thin-Film Morphologies
Authors: Maass Philipp
Published: July 2022

Understanding and control of cluster growth on solid surfaces is a subject of intensive research to develop materials with new properties. Of particular interest is the self-organized structure formation by deposition of atoms and molecules on surfaces, where the interplay of diffusion, nucleation, aggregation, segregation and superlattice ordering yields a rich variety of growth phenomena [1]. The resulting structures are often frozen-in non-equilibrium structures with properties distinctly different from the equilibrium bulk phases. Here I will discuss the role of second layer nucleation for three-dimensional cluster formation and its influence on cluster morphologies.

[1] M. Einax, W. Dieterich, P. Maass, Rev. Mod. Phys. 85, 921 (2013).
(Invited) The Role of Overpotential in Nucleation and Growth
Authors: Schwarzacher Walther
Published: July 2022

Overpotential, defined by IUPAC as the 'deviation of the potential of an electrode from its equilibrium value' is a key parameter in electrodeposition, as it is in other areas of electrochemistry. However, care is required when dividing the overpotential into contributions such as transport overpotential, activation overpotential etc. The concept of 'nucleation overpotential' is especially open to abuse, as I shall demonstrate with the help of examples from the literature. To avoid misunderstanding, it is necessary to recognize that when deposition takes place via the formation of reduced mobile adatoms, the key quantity for both nucleation and growth is the difference between the adatom chemical potential and the chemical potential of metal atoms at the so-called half-crystal position.
(Invited) Electrochemical Microcalorimetry, a Thermodynamic Approach to Metal Deposition Processes
Authors: Schuster Rolf
Published: July 2022

Electrochemical microcalorimetry measures the heat, which is evolved during an electrochemical process. With our experimental setup tiny electrochemical conversions down to a few percent of a monolayer are sufficient for the determination of the heat, which is evolved at a single electrode. This allows to stay close to equilibrium conditions and thus to determine the reversible contribution to the heat, which is directly proportional to the entropy changes during the electrochemical reaction, including all side reactions like codeposition processes, polarization of the double layer etc.. In this contribution we will present examples, how from the knowledge of the reaction entropy conclusions can be drawn i) on the solvation of Na ions for Na deposition from a diglyme electrolyte, ii) on the reactions steps for the reduction of Ag from Ag-cyanide complexes and iii) the deposition process of Cu2+ from aqueous solutions. We also will present first results of our attempts to measure the reaction volume of Cu bulk deposition and Cu UPD on Au(111) by pressure dependent potential measurements.
(Invited) Using Electrodeposition to Make Electrocatalysts
Authors: Gewirth Andrew A. , Chen Xinyi , Hua Qi
Published: July 2022

This talk discusses the use of electrodeposition to make electrocatalysts. We show that electrodeposition of CuAg or CuSn alloy films under suitable conditions yields high surface area catalysts for the active and selective electroreduction of CO2 to multi-carbon hydrocarbons and oxygenates. Alloy films containing Sn exhibit greater efficiency for CO production relative to either Cu along or CuAg at low overpotentials. In-situ Raman and electroanalysis studies suggest the origin of the high selectivity towards C2 products to be a combined effect of the diminished stabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag or Sn incorporated in the alloy. Sn-containing films exhibit less Cu2O relative to either the Ag-containing or neat Cu films, likely due to the increased oxophilicity of the admixed Sn. Incorporation of a polymer into the Cu electrodeposit leads to very active CO2 reduction electrocatalysis due to pH changes at the electrified interface. Vibrational spectroscopy is used to evaluate the pH at the interface during electrolyzer operation. Co-electrodeposition of polymers with other metals yields active electrocatalysts for other processes.
(Invited) Temperature Effects on Li Nucleation at Cu/Lipon Interfaces
Authors: Motoyama Munekazu , Hirota Masaharu , Iriyama Yasutoshi
Published: July 2022

This study reports the effect of temperature on Li nucleation at the Cu/lithium phosphorus oxynitride (LiPON) interface.1 Galvanostatic Li plating is performed on LiPON glass electrolytes at different temperatures ranging from 25 to 100 °C. At any temperature, the negative voltage peak appears, indicating Li nucleation, immediately after starting Li plating. The nucleation overpotential and nucleation number density decrease with increasing temperature. This is because the diffusivity of Li adatoms/ions along the Cu/LiPON interface increases with temperature, resulting in an increase in the amount of Li atoms incorporated into a single Li nucleus. The critical nucleation area also extends with increasing temperature. It is found that the activation energy for the interfacial diffusion of Li adatoms/ions along the Cu/LiPON interface is 51 kJ mol–1 (0.53 eV), which is close to the activation energy for Li+ conduction in LiPON.

Reference

M. Motoyama, M. Hirota, T. Yamamoto, and Y. Iriyama, ACS Appl. Mater. Interfaces,
12, 38045–38053 (2020).

Figure 1
Structure Specific Adsorbate Interactions at Electrodepositing Cu Interfaces
Authors: Raciti David , Hight Walker Angela , Moffat Thomas P
Published: July 2022

Mechanistic understanding of interfaces during additive based electrochemical deposition of thin films is limited by lack of tools to discretely probe given features of deposits. Modern spectroelectrochemical methods that have enabled significant understanding, like surface-enhanced Raman and infrared spectroscopies (SERS and SEIRAS, respectively), are restricted by specimen geometry; SERS is closely linked to the use of rough plasmonically active surfaces while SEIRAS measurements is constrained to thin IR transparent metal films. More recently, the application of Au@SiO2 core-shell nanoparticles as “vibrational reporters” on plasmonically inactive surfaces has enabled collection of site-specific vibrational data on well-defined single crystal surfaces whereby the nanoparticle serves to channel the plasmonic energy to the nanoparticle-substrate interface. The present work utilizes this technique, Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy (SHINERS) to track relative coverages of sulfonate, chloride and methylene moieties following super-conformal Cu electrodeposition on a patterned interface (Figure 1 a,b,d). Corroborated by computational finite-element results (Figure 1 c,d) and x-ray photoelectron spectroscopy measurements, the SHINERS measurements demonstrate that during early stages of electrodeposition, on an accelerator functionalized surface, the regions with more deposition have higher coverage of sulfonate species. As deposition continues dilation of the sulfonate concentration occurs following the continual decrease in surface area of the interface. Ultimately, this work reveals the benefit from the combined use of SHINERs, photoelectron spectroscopy and computational models to further our understanding of composite electroplating and resolve complex site-specific interfacial interactions.

Figure 1
Minimum Thickness of Continuous Cu Layers on Mo from Fluoride Free Electrolytes
Authors: Ahmadi Kamyar , Quaye Peter , Dole Nikhil , Joi Aniruddha , Brankovic Stanko
Published: July 2022

Mo as a refractory metal has physical properties which are of interest for applications in CIGS photovoltaic cells fabrication and for next generation of liners for Cu interconnects[1]. Therefore it is of fundamental and practical interest to develop a process for Cu metallization of Mo surfaces where contiguity and high coverage is achieved at minimum thickness. However, one of the obstacles that prevent readily use of Mo as substrate for Cu electrodeposition is tendency of its surface to form a high quality oxide[2]
,[3].The surface energy of Mo-oxide is much lower than Cu which results in sporadic 3D nucleation and low adhesion of Cu deposit[2]. The presented work addresses this fundamental problem by combining the knowledge/breakthroughs demonstrated in the field of electro-polishing of refractory metals such as Nb[4] with common pulse electrodeposition practice[1]
,[5]. A design of deposition pulse reverse potential/current function for Cu is presented which converts a Mo-oxide/Cu to a Mo/Cu interface. Elaborate measurements of the thin film impedance during the Cu growth complemented with Pb UPD decoration studies and AFM surface morphology analysis are presented. These data indicate that Cu layers reach full contiguity and coverage of the Mo substrate at the thickness level of 3-5 nm. Considering that common Cu electrodeposition bath chemistry for interconnects contains additives whose incorporation makes Cu deposit somewhat incompatible with photovoltaic layers[1], this work presents the Cu solution chemistry which is additive free and can serve as a base for further improvement of the specific Cu deposition processes depending on its application.

[1] . J. Bi et al, Journal of Power Sources, 326, (2011) 211.

[2] . D. Mercier et al, Journal of the Electrochemical Society, 160 (2013) 3103.

[3] . M. Pourbaix, Atlas of electrochemical equilibria in aqueous solutions. 2d English ed. 1974, Houston, Tex.: National Association of Corrosion Engineers.

[4] . Journal of The Electrochemical Society, 160 (9) E94-E98 (2013).

[5] . J.C. Puippe and F. Leaman, Theory and Practice of Pulse Plating, AESF, (1986).
(Invited) Electrodeposition of Dense Lithium and Sodium Battery Cathodes for Solid-State Batteries
Authors: Braun Paul V.
Published: July 2022

Conventional Li-ion batteries are formed using slurry-cast electrodes whose random nature and porosity limits both energy density and rate performance. Slurry-cast electrodes also are generally incompatible with solid-state batteries unless the slurry contains solid electrolyte particles in addition to active material. While such composite electrodes, consisting of a mixture of active material, solid electrolyte, and potentially conductive additives are under active investigation, such designs exhibit power and energy limitations due to the tortuosity of the ion and electron conduction pathways. I will present our work on the molten salt electrodeposition of thick and nearly dense Na and Li-based cathodes on metallic current collectors, including cathodes based on LiCoO2, NaCoO2, LiMn2O4, and Al-doped LiCoO2 which overcomes some of these challenges. The capacities are near-theoretical, and the crystallinities and electrochemical performance are comparable, or in some cases, even better than powders synthesized at much higher temperatures. A very attractive element of the electrodeposition process is control of the crystallographic orientation of the deposited film. For example, the crystallography can be oriented such that the fast electron and ion conduction directions are perpendicular to the substrate. Finally, I will discuss solid-state batteries built these electrodes and how the crystallography of the electrode | solid-electrolyte interface impacts interfacial reactions, rate performance, and cycle life.
(Invited) Structural Control of Molybdenum Silicide By Electrolytic Silicification of a Mo Substrate
Authors: Suzuki Yuta , Matsuo Yu , Shimizu Yosuke , Fukunaka Yasuhiro , Goto Takuya
Published: July 2022

Metal silicides are attracting attention as environment-friendly functional materials because they are composed of abundant elements in the earth’s crust. However, conventional processes for preparing silicides from SiO2 as the starting material consume a lot of energy and utilize hazardous materials through the reduction process of SiO2. Against this background, the electrochemical process in molten salt become key technology for fabricating silicon materials in an environmentally friendly, simple, and inexpensive process. We have already reported the electrodeposition of metallic silicon films from SiO2 in high temperature molten salt. This process has the potential to develop environmentally friendly and sustainable systems for fabricating silicon materials by combining non-consumable oxygen-evolving anodes. In this study, we focused on the electrochemical formation of molybdenum silicide from SiO2 in molten chloride because the molybdenum silicide are promising materials for ultra-high temperature protective coating, heating element, and thermoelectric conversion element.

We report here the electrochemical formation of molybdenum silicide in CaCl2-based molten chloride containing SiO2 system. A Mo substrate was used as the working electrode. From the results of characterization by XRD, SEM, and EDS analysis, a metastable β-MoSi2 phase and stable α-MoSi2 phase were obtained by controlling applied potentials during potentiostatic electrolysis. In addition, since the nucleation and growth process of the silicide is very important to control its structure, composition and morphology, the electrolytic time transient between molybdenum substrate/molten chloride interface were carefully observed by SEM analysis. The fundamental research on formation process of silicides in molten salt will greatly contribute to materials science in high temperature environment and developing the novel rout for fabricating silicon materials.
Thermal, Mechanical, and Electrical Characteristics of the Lithiated PEO/LAGP Composite Electrolytes
Authors: Huang Hong , Lee Jeremy , Rottmayer Michael
Published: July 2022

Lithium-ion batteries utilizing solid-state electrolytes have potential to alleviate safety issues, prolong discharge/charge cycle life, reduce packaging volume, and enable flexible design. Polymer-ceramic composite electrolytes are more attractive and recognized because the combination can remedy and/or transcend individual constituent’ properties. We have fabricated a series of free-standing composite electrolyte membranes consisting of Li1.4Al0.4Ge1.6(PO4)3 (LAGP), polyethylene oxide (PEO), and two different lithium-salts, i.e. LiBF4 and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). It is determined that the type of lithium salt can prevail the ceramic LAGP loadings on altering the thermal, mechanical, and electrical properties of the composite electrolytes.

In this paper, we will present the results and discuss the differences in the aspects of melting transition, mechanical reinforcement, and ionic conduction resulting from the two different lithium salts together with the content of LAGP ceramic fillers in the lithiated PEO/LAGP composite electrolytes. The changes in these three aspects can be ascribed to the different interactions between the polymer matrix and lithium salt in the composite setting.