bluuebunny/crossref_metadata_2025 huggingface dataset:
Design Principles for Heterointerfacial Alloying Kinetics at Metallic Anodes in Rechargeable Batteries
Authors: Zheng Kent J.X.
Published: February 2024

How surface chemistry influences reactions occurring thereupon has been a long-standing question of broad scientific and technological interest. Here we consider the relation between the surface chemistry at such interfaces and the reversibility of electrochemical transformations at rechargeable battery electrodes. Using Zn as a model system, we report that a moderate strength of chemical interaction between the deposit and the substrate—neither too weak nor too strong—enables highest reversibility and stability of the plating/stripping redox processes. Focused-ion-beam and electron microscopy were used to directly probe the morphology, chemistry and crystallography of the heterointerfaces of distinct natures. Analogous to the empirical Sabatier principle for chemical heterogeneous catalysis, our finding arises from the confluence of competing interfacial processes. Using full batteries with stringent N:P ratios, we show that such knowledge provides a powerful tool for designing key materials in highly reversible battery systems based on earth-abundant, low-cost metals such as Zn and Na.

Reference: Zheng, Jingxu, et al. "Design principles for heterointerfacial alloying kinetics at metallic anodes in rechargeable batteries." Science Advances 8.44 (2022): eabq6321.
Magnetohydrodynamic Redeposition of Cations Onto the Anode
Authors: Jang Hansaem , Roe Daniel , Teobaldi Gilberto , Cespedes Oscar , Cowan Alexander
Published: February 2024

Dissolution of metallic and metal-based catalysts occurs at the anode surfaces. The oxygen evolution reaction (OER) has been reported to cause the catalyst to be dissolved into cationic species during the electrolysis.[1–5] This phenomenon is not limited to non-noble metals (e.g. Fe, Co, Cu), but also occurs with noble metals (e.g. Ru, Rh, Pd, Os, Ir, Pt, Au).[1–4] Even with thermodynamically stable stoichiometric oxide catalysts, the dissolution cannot be completely avoided during the OER.[5] Upon dissolution, the as-formed cationic species will be attracted to the negatively charged cathode surface, resulting in catalyst loss from the anode over time.

Mass transport in diffusion layers during electrochemical reactions can be tuned by means of magnetohydrodynamics (MHD). This magnetic convection is a result of the Lorentz force that arises when there is an angular mismatch between the magnetic field and the local current density. Therefore, in the presence of a magnetic field, vortices can be generated around microscale protuberances on the electrode surface, and this phenomenon is often referred to as micro-MHD.[6] Conventional applications of MHD include cathodic electrodeposition and anodic corrosion or electropolishing studies. The difference in application according to the redox tendency of the target reaction is electrochemically rational on the basis of E
H–pH diagrams.

Despite a rather elusive combination, we presume that the magnetically-induced vortex can contribute to the electrochemical redeposition of as-dissolved cationic species onto the anode surface. Provided that a vortex can enhance the retention of the cations remaining in the vicinity of the surface, the chance of oxidative electrodeposition will increase. If this is the case, the protuberances on the anode are expected to grow under magnetic fields over the course of the OER. This will be realized as a result of facilitated O2 bubble detachment or increased local ionic concentration, or both.

In this work, we present that the morphology of the anode surface can change in the presence of a magnetic field. For the demonstration, we prepare a nanometrically-flat electrode consisting of a magnetic superlattice and an electrocatalyst layer. We perform the OER on the flat catalyst surface using magnetic and nonmagnetic samples and compare micrographs of pre-experimental and post-experimental sample surfaces. The findings show that the protuberances build up along their axes on the magnetic sample surface whereas the nonmagnetic sample involves the flattening of the surface.

References

[1] Angew. Chem. Int. Ed. 60 (2021) 13343–13349

[2] J. Electrochem. Soc. 161 (2014) H822

[3] J. Phys. Chem. Lett. 5 (2014) 2474–2478

[4] ChemCatChem 6 (2014) 2219–2223

[5] Nat. Catal. 1 (2018) 508–515

[6] Electrochem. Commun. 442 (2014) 38–41

Figure 1
Gold Ultralow Loading on Nickel Foam for Nitrogen Electrochemical Reduction
Authors: Milazzo Rachela Gabriella , Tranchida Giuseppe , Leonardi Marco , Scalese Silvia , Condorelli Guido Gugliemo , Lombardo Salvatore , Privitera Stefania M. S.
Published: February 2024

Gold electroless deposition on nickel foam offers several advantages over traditional electrodeposition techniques. One of the main advantages is that it can produce uniform thickness coatings on complex shapes and geometries, such as porous and three-dimensional substrates like nickel foam. The resulting gold-nickel foam composite has high surface area and good electrical conductivity, making it suitable for various electrochemical applications, including catalysis, sensing, and energy storage.

In this work we focused on the development of synthetic strategies to grow and optimize the surface coverage of gold on nickel foam and the evaluation of its suitability for the electrochemical reduction of nitrogen for ammonia synthesis.

The gold electroless deposition on Ni Foam has been obtained by immersion in aqueous solution containing KAuCl4 and HCl, with or without stirring and addition of a surfactant agent (Isopropyl Alcohol). Depositions were performed by varying the immersion time from 30 seconds to 30 minutes. Scanning electron microscopy (SEM) has been employed to compare different deposition conditions and to optimize the morphology of the nanofilms, allowing higher catalytic activity. The electrochemical performance of the gold deposited on nickel foam was evaluated in a standard two compartments electrochemical cell using a Pt wire as counter electrode (CE), a saturated calomel electrode (SCE, saturated KCl) as reference and 0.1 M Na2SO4 solution as electrolyte. Electrochemical active surface area (EASA) and linear sweep voltammetry (LSV) have been adopted to evaluate the active area and the overpotential toward hydrogen evolution reaction (HER). Chronoamperometry experiments were carried out at various potentials to evaluate the performance of the catalyst for the electroreduction of nitrogen and ammonia synthesis.

The amount of ammonia produced was measured by the indophenol blue method.

The maximum NH3 yield of 2.8x10-11 mol s-1 cm-2 was achieved at -0.045 V vs RHE. The maximum faradaic efficiency of 5.8% was achieved at more positive potential (0.015 V vs RHE) due to the HER.

The results show that the gold on nickel foam exhibits excellent electrochemical stability and high conductivity.

This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No 101006941. This project started on the 1st of November 2020 with a duration of 42 months.
Metal Filled Nanostructured Silicon a Platform to Interlink Magnetism and Optics
Authors: Granitzer Petra , Rumpf Klemens , Gonzalez-Rodriguez Roberto , Coffer Jeffery
Published: February 2024

This presentation deals with the utilization of nanostructured silicon (porous silicon and silicon nanotubes) for deposition of various metals, especially magnetic ones, within the pores/tubes. The novel magnetic properties of the semiconducting/magnetic composites which arise due to the nanoscopic size of the used materials are investigated with respect to optical and magnetic on-chip applications.

Porous silicon is fabricated by anodization of a silicon wafer in an aqueous hydrofluoric solution. The morphology of the porous structures depends on the doping density of the used wafer and on the applied current density as well as the electrolyte concentration. The ferromagnetic metals are deposited within the porous structures electrochemically in using the corresponding metal salt solution as electrolyte. A modification of the electrochemical parameters results in adjustable size and shape of the deposits. Ni and Co, both metals are electrodeposited within the nanostructured silicon in using aqueous NiSO4 and CoSO4 solutions by applying a current density between 10 and 20 mA/cm2 and a frequency between 0.05 and 0.2 Hz.

One of our key topics is luminescent porous silicon loaded with magnetic metals to enhance the photoluminescence, with the final aim to influence/control the optical properties by a magnetic field. The metal deposits affect the optical properties but also give rise to specific magnetic behavior (1). Due to the metal filling of the porous silicon the photoluminescence is blue-shifted and furthermore an increase of the intensity is observed. The influence of the magnetic metal filling on the optical properties (photoluminescence, decay time) is discussed, and the magnetic characterization of the nanocomposites is presented.

A further issue, the deposition of hard and soft magnetic materials within the nanostructures, aiming in the fabrication of arrays of permanent nanomagnets is presented (2). Here the investigation of the magnetic behavior of bi-metal nanostructures within nanostructured silicon with the aim to exploit the magnetic properties of both metals and gain control of the exchange coupling between the two metals especially with respect to their volume ratio is discussed. Furthermore, a variation of the structure size and the proximity of the metal deposits modify the exchange coupling and thus the energy product. Nanocomposite systems with an energy product as high as possible should be achieved to give rise to on-chip applications using permanent nanomagnets, especially arranged in arrays.

(1) P. Granitzer, et al, Frontiers in Physics, 8 (2020) 121

(2) K. Rumpf, et.al, Phys. Stat. Sol. A, 217 (2020) 1901040
Cathodic Deposition of Conductive MOF Films: Mechanism and Applications
Authors: Xie Sijie , Fransaer Jan
Published: February 2024

Conductive metal-organic frameworks (MOFs) are porous yet electric conductive, promising for many applications such as electronics, electrocatalysts, and energy storage. However, traditional solvothermal and microwave synthesis methods usually lead to MOF powders that cannot be used directly, i.e., additional processes like adding binders, casting, and thermal treatments are required for their applications. Therefore, shaping conductive MOFs into 2D thin films is attracting attention from researchers. Here we report a cathodic deposition for the one-step fabrication of conductive MOF films, which features a fast and convenient deposition process. In this method, the deposition precursor contains metal salts and organic linkers (no supporting electrolyte is needed). When an external negative bias is applied on the conductive working electrode (WE), the linkers can be deprotonated on its surface. A conductive MOF film can thus be deposited on the WE by coordinating the deprotonated linkers and metal nodes. As demonstrating examples, Cu/Ni-HHTP (HHTP: 2,3,6,7,10,11-hexahydroxytriphenylene) and Cu-BTPA (BTPA: benzene-1,3,5-triyltriboronic acid) are cathodically deposited on indium-doped tin oxide (ITO) glass substrates. The measured conductivity of these deposited conductive MOF films varies from 0.01 to 0.1 S cm-1 depending on their thickness and composition. Both of the fabricated conductive MOF films show good performance on supercapacitors and electrochemical sensing.
Influence of Moisture on the Electrochemical Performance of Prelithiated C/SiOx Composite Anodes for Li-Ion Batteries
Authors: Fenske Hans , Lombardo Teo , Gerstenberg Jessica , Steckermeier Dominik , Kern Christine , Janek Jürgen , Kwade Arno
Published: February 2024

Prelithiation of Si containing anodes has commonly been acknowledged as a potential solution to the challenge of the high irreversible lithium losses that still hinder the widespread adoption of this next-generation anode active material. However, upscaling and implementation in the process chain remain major hurdles for most proposed prelithiation processes. A significant part of this comes down to the high reactivity of prelithiation agents and prelithiated electrodes towards moisture. In industrial scale electrode production, dry rooms with dew point controlled atmospheres are already in use, but are a significant cost factor. Therefore, the compatibility of prelithiated electrodes with dry room conditions is a major factor for the implementation of prelithiation into existing production lines.

In this work C/SiOx composite anodes are electrochemically prelithiated and subsequently subjected to industry relevant moisture levels. The influence of dew point and exposure time is examined. After exposure, the anodes are assembled into half-cells and their electrochemical performance during the first lithiation/delithiation cycle is analysed using a 3-electrode setup. The evaluation of the specific capacities and the potential curves provides information about the extent of the damage to the electrode. The results indicate a promising stability window for dew points of up to -40° C and realistic exposure times of up to one hour. Additional aging investigations in full cells against NMC622-based cathodes confirm these findings. Furthermore, electrochemical impedance spectroscopy, XPS and ToF-SIMS measurements are performed to elucidate the effect of moisture exposure on the solid electrolyte interface (SEI) composition. The results suggest the development of a double-layered SEI structure, where the first layer forms during prelithiation and is altered by moisture exposure, while the second layer forms on top of the first layer during formation.

Figure 1
Revealing the Rate-Limiting Electrode of Lithium Batteries at High Rates and Mass Loadings
Authors: Chen Yongxiu
Published: February 2024

Lithium-ion batteries with superior capacities and rate performance are needed due to the soaring demands for even higher energy and power device requirements. [1-2] However, the main hurdle on achieving this predominately results from poor rate performance of the electrode, related to thermodynamic limitations and slow kinetics. To determine the rate-limiting electrochemical processes in a NMC622 vs graphite cell, a methodology based upon the galvanic intermittent titration technique, for investigating the diffusion coefficient and rate kinetics from the observed overpotential at each electrode has been developed. Variable current densities have been used to simultaneously extract the thermodynamic and kinetic properties of each electrode with increasing mass loading. Graphite is observed to reach its thermodynamic limits quicker than NMC, due to the flat plateaus and overpotentials observed from the charge transfer kinetics and mass transport. At high rates and high mass loadings, the graphite electrode is responsible for limiting both lithium-ion diffusion and reaction rates in the full cell. Slow diffusion kinetics are caused by the transport of the electrolyte in the porous electrode, which limits the availability of lithium for reaction at the surface of the graphite. This current interrupt testing methodology is proposed as a fast single technique for comprehensively parameterizing the rate limitations observed in a full cell configuration [3].
Electrochemical Passivation of Aluminum As a Current Collector for Solid-State Polymer Batteries : PEO/LiTFSI Polymer Electrolyte
Authors: Kim Sun , Kim Sun
Published: February 2024

Investigation of the electrochemical properties and passivation mechanism of aluminum as a current collector for solid-state polymer batteries is carried out. Herein, electrochemical stabilities of Polyethylene glycol (PEO) based solid-state electrolyte containing Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt are proved using electrochemical dynamic- and transient-mode polarization with surface scratching. These results indicate that Al metal undergoes passivation with a layer below 4.5 V vs. Li+/Li. And then Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) reveal double layers are formed during the passivation on Al metal surface, with the outer layer composed of metal fluorides (AlF3) and the inner layer composed of metal oxides (Al2O3). The formation of the AlF3 layer on Al metal surface is attributed to the reaction between Al2O3 and HF following as Al2O3 + 6HF → 2AlF3 + 3H2O. Therefore, successful passivation achieved by the formation of AlF3 on the Al2O3 surface of Al metal facilitates to be widely used as a current collector for lithium metal polymer batteries. Therefore, successful passivation by the formation of AlF3 on the Al2O3 surface of Al metal making it a promising choice for the positive electrode in lithium metal polymer batteries.
Optimizing Extreme Fast Charging Strategy for Lithium-Ion Batteries: A Model Predictive Control Approach
Authors: Kim KyungHyun , Choi Jung-Il
Published: February 2024

With the increasing demand for extreme fast charging (XFC) in electric vehicles (EVs), there is an urgent need to develop health-conscious fast charging strategies for lithium-ion batteries. However, simply increasing the charging current can disproportionately accelerate battery aging, resulting in severe capacity and performance loss, while posing unacceptable safety risks during operation. In addition, the battery management system (BMS) needs to know the state of each cell for reliable and accurate management, but this involves significant computational burden. In other words, new fast charging strategies need to be developed to solve the dilemma between charging rate, battery aging, and computational complexity.

In this work, we propose a novel framework for modelling, estimating, and balancing different types of state heterogeneities in a multi-cell battery module. This framework facilitates the development of optimal fast charging strategies based on battery electrochemical models and model predictive control (MPC). First, an electrochemical and thermal coupling model is formulated at the unit cell level, and a module model is formulated at the system level, taking into account various factors such as connection resistances and system terminals. Then, a non-linear MPC is used to achieve fast charging while considering the health of the battery module. Battery performance is tracked by accurately estimating the battery's internal state, which can support the balancing of all state heterogeneity types represented in the model by controlling the charging current according to the internal state. The proposed framework has three main advantages: (1) The modelling strategy has a flexible and configurable structure that can be applied to battery modules of any size. Using this, (2) the internal state of the battery can be estimated with reduced computational complexity. (3) MPC can be applied to cell-to-cell balancing and XFC strategy. The results of the proposed method provide important insights for achieving XFC and show promise for real-time online estimation and control.

Figure 1
Enhanced Lithium Ion Diffusivity of Nanosized Li1.2Mn0.8O2 Cathode Material Via Na and Ti Co-Doping
Authors: Ledwaba Raesibe Sylvia , Ngoepe Phuti Esrom
Published: February 2024

Ionic doping is amongst the most effective modification methods capable of altering the local atomic environment, which in turn governs the redox reactions and electrochemical performance of Li-rich cathode materials. It has been demonstrated to improve bulk structural stability and suppress oxygen loss to some extent. Independently doping with Na and Ti has sparked interest in them however, very little is understood about their combined impact in a quest to address the structural complexities encountered during the operation of Li-rich cathodes. Herein, molecular dynamics simulations were carried out on both the bulk and nanospherical structures of Li1.2Mn0.8O2, Li1.2Mn0.72Ti0.08O2, and Li1.15Na0.05Mn0.72Ti0.08O2 whereNa+ doping in the Li-site and Ti in the Mn site. The temperature variations were between 300K and 2000 K. The findings of this study depict that bulk structures have diffusion coefficients that are orders of magnitude less than those of nanospherical structures. This strongly supports the unique capabilities of nanoparticles in reducing the Li-ion diffusion distance and increasing the contact area between the electrode and the electrolyte. In terms of variation in doped systems, it was observed that singly doping the layered structure with titanium slightly increases ionic diffusion in the Li-Rich structure whereas, co-doping the same structure yields even higher diffusion coefficients. These are possible results of enhanced interlayer spacing as Na generally has a larger ionic radius than Li. Furthermore, the co-doping may have contributed to structural stability wherein cationic mixing influenced by Mn migration in pure Li1.2Mn0.8O2 is largely reduced [1]. This places the two dopants at the pinnacle of capacity enhancement for the Li-rich electrode and sparks significant interest in further performance and structural stability studies.

References

[1] Ledwaba, R.S., Tsebesebe, N.T. and Ngoepe, P.E., 2022. Journal of The Electrochemical Society, 169, p.110502.
Impact of Metallic Impurities on the Synthesis and Properties of NMC Cathode Material Obtained by Co-Precipitation
Authors: Chable Johann , Bohn Nicole , Raab Monika , Geßwein Holger , Bergfeldt Thomas , Binder Joachim R.
Published: February 2024

Among the different factors that influence lithium-ion batteries (LIB) performances, the properties of the cathode active material (CAM) play a crucial role. The composition, the crystallinity and also the particle size and morphology of these materials are part of the major parameters governing the CAM behaviour. These parameters are strongly dependent of the synthesis method, especially in the case of the hydroxide precursor of the layered LiNixMnyCozO2
[1].

One of the most widely spread synthesis method of such precursors is the synthesis by co-precipitation, where metal salts of Ni, Mn and Co are precipitated together in a continually-stirred tank reactor (CSTR) in carefully controlled pH- and temperature conditions[2]. Any parameter of the co-precipitation must be precisely tuned to obtain the desired material, as highlighted in the figure here after.

Considering the increasing presence of wanted (coating/doping)[3] and unwanted (impurities after recycling)[4] elements in the co-precipitation process, extensive knowledge of their impact on it is of great interest. Therefore, the synthesis of NixMnyCoz(OH)2 was conducted by co-precipitation with the controlled addition of increasing amounts of elements such as Cu and Al.

The effects of these additions were investigated by thoroughly characterizing the morphology of the obtained hydroxides with the help of SEM, BET, particle size distribution and porosity measurements. The composition of the synthesized hydroxides was determined by the ICP-OES technique. The possible influence on the further step of CAM synthesis, i.e. calcination, was followed by in-situ X-Ray thermodiffraction and the electrochemical performances were assessed by galvanostatic cycling the obtained CAM in lithium half-cells. This helped to evidence the varying impact of the added elements, depending on their concentration in the synthesis process.

This work is supported by the German Ministry for Economy and Climate Protection (BMWK).

References

[1] Malik, M., et al., Materials Today Energy, 2022, 28, 101066

[2] Van Bommel, A., Dahn, J.R., Chemistry of Materials, 2009, 21, 1500-1503

[3] Feng, Z. et al., ACS Applied Materials and Interfaces, 2021, 13, 43039-43050

[4] Kim, S. et al., Journal of Alloys and Compounds, 2021, 857, 157581

Figure 1
Niobate Anodes for High Rate Lithium-Ion Batteries
Authors: Huijben Mark , Xia Rui , Zheng Jie , Jager Maarten , Boukamp Bernard , Kaghazchi Payam , ten Elshof Johan E.
Published: February 2024

Fast charging is one of the key performance requirements for next generation lithium ion batteries, and is directly related to the ease of ionic and electronic transport. However, lithium ion diffusion rates of promising anode materials, such as Li4Ti5O12, anatase TiO2, T-Nb2O5 and Nb18W16O93, are still insufficient. Therefore, nanosizing of the active electrode material is a common strategy to increase the effective lithium ion diffusion transport rate, which unfortunately also decreases the volumetric energy/power density and stability of the battery.

Recently, we demonstrated nickel niobate, NiNb2O6, for the first time as a new intrinsic high-rate electrode material,[1] which exhibits an intrinsic high rate performance enabled by its suitable host crystal structure without the requirement of realizing nano-architectures. The NiNb2O6 host crystal structure exhibits only a single type of channel for lithium ion intercalation and can be fully lithiated up to Li3NiNb2O6 with a capacity of about 244 mAh/g at low current densities. Interestingly, a high diffusion coefficient of 10-12 cm2/s at 300 K enables fast (dis)charging at high current densities resulting in high capacities of 140 and 50 mAh/g for respectively 10C and 100C. The minimal volume change during lithiation is the origin of the stable reversible lithiation process in NiNb2O6 and leads to a capacity retention of 81% after 20.000 cycles at 100C. The structural stability and electrochemical behaviour were investigated by various experimental techniques and confirmed by density functional theory (DFT) calculations. Finally, full cell systems against LiFePO4 and NCM811 cathodes demonstrate the promising energy storage performance of nickel niobate anodes in practical battery devices.

Our results strongly suggest that niobate-based materials are intrinsic high-rate anode materials without the requirement of realizing nano-architectures as typical for numerous titanium- and niobium-based oxides through complex synthesis procedures to minimize the length scales for lithium diffusion. Recently, we have replaced nickel by other transition metal ions to widen the exploration of niobate compounds for fast lithium ion diffusion. Large variations in electrochemical performance are observed, and the latest results will be presented. This will provide a new perspective on the role of intrinsic high-rate electrode materials for realizing ultrafast anode materials for future energy storage devices.

[1] R. Xia et al., Advanced Energy Materials 12 (2022) 2102972.
Machine Learning Based Identification of Lithium-Ion Battery Cell Chemistries
Authors: Wett Christopher , Goerick Dominik , Turan Bugra
Published: February 2024

With a rapidly growing market for lithium-ion batteries in commercial applications and electrical vehicles, it is foreseeable, that in upcoming years a large number of batteries will return to manufacturers, recycling companies and testing facilities. Unfortunately, recycling companies already struggle with the fast identification of used and unknown batteries. Especially for the material re-use, a profound knowledge of the cell chemistry and its mass fraction is crucial. As of today, this issue is barely discussed in lithium-ion battery research as the focus mainly lies on battery simulation and state estimation.

In this work, we present a machine learning based approach for the fast identification of unknown cell chemistries. The approach makes use of differential voltage analysis (dV/dQ) of open circuit voltage (OCV) curves for the training of the machine learning model. The training data was synthetically generated using electrochemical models from PyBaMM. Significant model parameters like the amount of cyclable lithium and the ambient temperature were used to create thousands of differently aged models under different conditions. Besides training the model for lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxides (NMC) cell chemistries, two NMC cells with different mass fractions (811 and 532) were used for training and testing.

Different machine learning approaches like decision trees, support vector machine classifiers and different ensemble learning methods were tested and compared against each other. Each of them showed excellent forecast accuracies for the tested chemistries. Moreover, the method was validated by successfully identifying measured OCV curves of real cells. Analysis of the identification techniques showed that the models only need a few significant points to distinguish the chemistries. Hence, the number of OCV points and the duration of the identification time can be drastically reduced for real world applications. In a next step, the OCV curves may even be reduced to partial curves.

The proposed method is a promising way of reliably identifying lithium-ion battery cell chemistries in a short time frame. It furthermore provides a straightforward solution for a neglected issue, that will most likely occupy battery research in the future.

Figure 1
Revealing Phase Transition in Ni-Rich Cathodes Via Nondestructive Entropymetry Method
Authors: Nuroldayeva Gulzat , Uzakbaiuly Berik , Adair Desmond , Bakenov Zhumabay
Published: February 2024

With the expanding requirements of recent energy regulations and economic interest in high-performance batteries, the need to improve battery energy density and safety has gained prominence. High-energy-density lithium batteries, employed in next-generation energy storage devices, rely on nickel-rich cathode materials. Since these have extremely high charge/discharge capacity, high operating voltage, prolonged cycle life, and low cost, nickel-rich cathode materials such as Ni-rich NCM (LiNix>0.8CoyMnzO2) and Ni-rich NCA (LiNix>0.8CoyAlzO2) are of particular interest to researchers. Several in situ characterization methodologies are currently used to understand lithium-ion battery electrode response and deterioration better. Nevertheless, in many contexts, these measurement methodologies must be combined with specially designed cells and electrode materials with distinct forms, which is sometimes inconvenient. As an alternative, thermothermo-voltametric dynamic characterization may be utilized to describe the thermal internal characteristics of various electrode materials, such as the structural changes and electrode reactions that occur during charging and discharging. In this paper, a non-destructive entropy measurement method demonstrates that phase change occur for NCM (LiNi0.83Co0.12Mn0.05O2) and NCA (LiNi0.88Co0.09Al0.03O2) at 40-30% of SOC and 90-80% of SOC, respectively. This is confirmed by ex-situ X-ray diffraction measurements for these highly popular cathodes.
Enhancing the Performance and Stability of Li-Ion Batteries with Fluorinated Electrolytes: Insights from MD Simulation and Experimental Analysis
Authors: Homlamai Kan , Sawangphruk Montree
Published: February 2024

The significance of using fluorinated electrolytes, particularly fluorinated ethylene carbonate (FEC) and difluoro ethylene carbonate (DFEC), in the electrolyte system of 1.2 M LiPF6 in dimethyl carbonate (DMC)/fluorinated solvent (FEC/DFEC), was explored using classical molecular dynamic (MD) simulation and density functional theory (DFT) calculation in this work. Various parameters, such as radial distribution function (RDF), integral over RDF, transference number, coordination number, and solvation energy, were analyzed. The study demonstrated that DFEC enhances the reduction in binding energy of the solvation sheath compared to FEC. Additionally, the electrochemical performance of a practical full-cell 18650 of LiNi0.88Co0.10Al0.02O4 (NCA) cathode and graphite anode batteries was examined, confirming that 1.2 M LiPF6 in DMC/FEC/DFEC (4:0.5:0.5 %v) demonstrated the highest capacity retention after 1,000 cycles, surpassing 1.2M LiPF6 in DMC/fluorinated (4:1 %v, FEC and DFEC, respectively) and the previous electrolyte 1.2 M LiPF6 in EC/EMC/DEC/FEC (1:1:1:1.3 %V). Spectroscopy techniques, including DEMS, NMR, and GC-MS, were utilized to investigate the electrolyte decomposition, revealing CO2 and H2 as the main gas products during decomposition. NMR results identified some species, such as HF, H2O, acetal, formaldehyde, and unknown products, while GC-MS confirmed that all the solvents in the electrolyte take part in the decomposition process. This study highlights the potential of fluorinated electrolytes in battery systems and provides insight into their decomposition mechanism, contributing to the development of more efficient and stable battery systems.
Li3InCl6-Coated High-Voltage Cathodes for Thiophosphate-Based Solid-State Li Batteries
Authors: Jin Feng , Fadillah Laras , Mehraj Ud Din Mir , Rettenwander Daniel
Published: February 2024

Solid-state Li batteries are pursued as potentially safe and stable high-energy storage systems. However, key issues remain unsolved, impeding the practical realization.[1] One of the fundamental reasons for the failure of these batteries is likely the instability of solid-state electrolytes, such as Li6PS5Cl, towards high voltage cathodes. To mitigate the interface instability issues coating materials that prevent the decomposition of the solid-state electrolytes without limiting the ionic transport across them are thus urgently warranted.[2,3] Halides have been shown to have excellent high voltage stability up to 4.2 V in combination with moderate Li-ion conductivities of the order of magnitude ~10-3 S cm-1.[4]Combining the properties of halides with sulfides, hence, could be a promising strategy to enable room temperature solid-state Li batteries. Therefore, we synthesized nano-sized Li3InCl6 powder by mechanochemistry.Thereafter, Li3InCl6 was coated onto micrometer-sized LiNi0.8Co0.15Al0.05O2 (LIC@NCA) cathode particles using mechanofusion technique. The thickness and uniformity of the coating were investigated using FIB-SEM and TEM. The coating thickness has been found to be as thin as 200 nm nanometers fully covering the NCA particles. Finally, LIC@NCA particles have been tested in a solid-state Li batteries using Li:In-alloy as anode and Li6PS5Cl as SSE. Cells with LIC@NCA show a significant improvement (from 60 mAh/g to 150 mAh/g) in respect of the initial capacity loss and capacity fading compared to the pristine NCA.

References

[1] Janek, J. and Zeier, W.G., 2016. A solid future for battery development. Nat Energy, 1(9), 1-4.

[2] Lewis, J.A., Lee, C., Liu, Y., Han, S.Y., Prakash, D., Klein, E.J., Lee, H.W. and McDowell, M.T., 2022. Role of Areal Capacity in Determining Short Circuiting of Sulfide-Based Solid-State Batteries. ACS
Appl
Mater
I
nterfaces, 14(3), 4051-4060.

[3] Zeng, D., Yao, J., Zhang, L., Xu, R., Wang, S., Yan, X., Yu, C. and Wang, L., 2022. Promoting favorable interfacial properties in lithium-based batteries using chlorine-rich sulfide inorganic solid-state electrolytes. Nat commun, 13(1), 1-13.

[4] Li, X., Liang, J., Luo, J., Norouzi Banis, M., Wang, C., Li, W., Deng, S., Yu, C., Zhao, F., Hu, Y., Sham, T.-K., Zhang, L., Zhao, S., Lu, S., Huang, H., Li, R., Adair, K. R., Sun, X. Air-stable Li3InCl6 electrolyte with high voltage compatibility for all-solid-state batteries. Energy Environ. Sci., 2019, 12, 2665-2671.

Acknowledgement

We acknowledge financial support by Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association (Christian Doppler Laboratory for Solid-State Batteries).
Solvent-Driven Degradation of Ni-Rich Cathodes Probed by Operando Gas Analysis
Authors: Temprano Israel , Dose Wesley M. , De Volder Michael F. L. , Grey Clare P.
Published: February 2024

High-capacity Ni-rich layered metal oxide cathodes are highly desirable to increase the energy density of lithium-ion batteries. However, these materials suffer from poor cycling stability, which is exacerbated by increased cell voltage due to higher interfacial reactivity than their lower Ni-content analogues. Here, we study the pivotal role of electrolyte solvents in determining the interfacial reactivity at charged LiNi0.33Mn0.33Co0.33O2 (NMC111) and LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes by using both single-solvent model electrolytes and the mixed solvents used in commercial cells (1, 2).

Operando gas analysis reveals that the solvent-dependent reactivity for Ni-rich cathodes is related to the extent of lattice oxygen release and accompanying electrolyte oxidation. We demonstrate here the detrimental effect of ethylene carbonate (EC), a core component in conventional electrolytes, when NMC811 is charged above 4.3 V vs Li/Li+ - the observed onset potential for lattice oxygen release. Oxygen loss is enhanced by EC-containing electrolytes and correlates with more electrolyte oxidation/breakdown and cathode surface degradation, which increase concurrently above 4.4 V. The gas analysis also reveals the crosstalk effect caused by the products of the nascent oxygen from the NMC811 lattice and the electrolyte solvent, showing anodic reactivity. In contrast, NMC111, which does not release oxygen up to 4.6 V, shows a similar extent of degradation irrespective of the electrolyte. Higher lattice oxygen release with EC-containing electrolytes is coupled with higher interfacial impedance, a thicker oxygen-deficient rock-salt surface reconstruction layer, more electrolyte solvent and salt breakdown. Oxygen loss is suppressed in the EC-free electrolyte, highlighting the incompatibility between Ni-rich cathodes and conventional electrolyte solvents.

W. M. Dose et al., Onset Potential for Electrolyte Oxidation and Ni-Rich Cathode Degradation in Lithium-Ion Batteries. ACS Energy Letters
7, 3524-3530 (2022).

W. M. Dose et al., Electrolyte Reactivity at the Charged Ni-Rich Cathode Interface and Degradation in Li-Ion Batteries. ACS Applied Materials & Interfaces
14, 13206-13222 (2022).

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Potential and Limitations of Research Battery Cell Types for Electrochemical Data Acquisition
Authors: Smith Anna , Stüble Pirmin , Hofmann Andreas , Leuthner Lea , Jeschull Fabian , Mereacre Liuda
Published: February 2024

Developing new electrode materials or electrolytes for lithium-ion batteries requires reliable electrochemical testing thereof. In academic research, coin-type cells and small pouch-type cells are commonly being assembled for this purpose. In our study [1], using commercial highly homogeneous and robust LiNi0.33Mn0.33Co0.33O2 (NMC111) cathodes, graphite anodes and 1M LiPF6 in EC/DMC with 3% VC as the electrolyte, four experienced researchers from the Institute for Applied Materials at Karlsruhe Institute of Technology assembled a variety of coin cells within a round robin test. For different cell building parameters, the battery lifetimes systematically varied from a few hundred to well over 2000 cycles before a capacity retention of 80 % was reached. As a benchmark, the same electrodes and electrolyte were incorporated as single- and multi-layer electrode stacks into pouch-type cells and reach almost 4000 cycles with a rate of 1 C.

Missplacing of electrodes and varying amount of electrolyte within a coin-cell were already addressed as performance influencing factors in the literature. In this study, one clear outcome with high impact on previously collected electrochemical data on coin cells, is that the steel grade of cell parts, as well as the in-housed total height of the electrode stack have dramatic influence on cell lifetime and the quality of the acquired electrochemical data. We present our best practice for coin cell manufacturing resulting from the round robin test. Further, it is shown that inappropriate testing conditions like poor cell contacting and cycler settings have additional impact on data collection. In this regard, we emphasize essential parameters for obtaining high quality data.

Additionally, using the same electrodes, we show direct rate performance differences of calendered vs. uncalendered electrodes, as well as half vs. full-cell test results by means of rate capability and long-term cycling stability. While compression of anodes is less crucial for rate capability, substantial differences are measured in case of the cathodes, highlighting the importance of sufficient cathode densification. Moreover, for long-term capacity retention studies, it is demonstrated that electrode densification of both, cathode and anode is crucial for high long-term capacity retention.

Our results are bridging the gap between lab research and industry-type battery cells. It is shown how key performance parameters can be projected from corresponding lab scale battery cell data, if certain important criteria are met vs. where the projections have their limits.

[1] A. Smith, P. Stüble, L. Leuthner, A. Hofmann, F. Jeschull and L. Mereacre, Batteries & Supercaps 2023, e202300080.

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Crossover Understanding of a Hydrogen Peroxide Electrosynthesis Device By Combining Oxygen Reduction and Organics Oxidation Reaction
Authors: Ding Penghui , Vagin Mikhail Yu. , Gueskine Viktor , Crispin Xavier
Published: February 2024

Hydrogen peroxide (H2O2) is a highly useful and green liquid chemical for daily life and industry. It is traditionally employed in wood industry, food packaging, fine chemicals synthesis and environmental depollution. Moreover, it is recently considered in the context of energy storage and conversion such as metal–hydrogen peroxide batteries since the world is trying to find high energy density batteries to replace lithium-ion batteries for electric vehicles and electrified aircraft [1].

Electrochemical production of H2O2 driven by cheap renewable electricity has emerged recently as an alternative to non-sustainable anthraquinone oxidation (AO) process. The recent surge of H2O2 electrosynthesis studies is mainly focused on advanced H2O2 production catalyst design aiming at achieving high activity and selectivity during the last couple of years [2]. As an essential part of H2O2 electrochemical reactors, anode reaction/process is given very little attention among investigators until recently. Water oxidation is the most used anodic reaction, but it suffers from high energy input, the use of expensive catalyst, and low-priced oxygen gas generation. This problem might be mitigated by using alternative organics oxidation processes with the possible generation of value-added products [3]. In order to be economically viable for these systems above, the organics in anode reservoir should not transport to the cathode part through the membrane. However, organic molecules crossover has already been identified in direct alcohol fuel cells and CO2 electrolyzers. Such organics crossover, to the best of our knowledge, has never been considered in previous reports on hydrogen peroxide electrosynthesis devices.

We use conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) for ORR via a two-electron pathway to H2O2. 4,5-Dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate (BQDS) was used as a model organic molecule since its oxidation process does not require catalysts as a typical electrolyte used in redox flow batteries. We investigated electrolyte and electric field effects on crossover and H2O2 production.

[1] Chem Catal. 2023, 3, 100568

[2] Nat. Rev. Chem.2019, 3, 442

[3] Nat. Energy
2021, 6, 904
Application of Industrial-Scale Lithium Sulphate Electrolysis in Battery Recycling
Authors: Boyd Tony , Brereton Clive , Moulson Jeremy , Wolfs Warren , GLynn Luke
Published: February 2024

As the world charges towards electrification and sustainable transportation, it is critical that the entire supply chain is equally sustainable. Industrial processes must be tailored towards circular processes in which emissions and effluents to the environment are minimized, if not eliminated altogether. When it comes to the production of battery grade lithium hydroxide monohydrate, a critical component of lithium ion batteries (LIBs), and the recovery of the lithium in spent LIBs. NORAM Electrolysis Systems Inc (NESI) has developed electrochemical technologies in which effluents are greatly reduced.

NESI has developed a flexible, multi-compartment industrial electrolyser for salt splitting (NORSCAND®) applications including electrolysis of lithium sulphate to produce battery-grade lithium hydroxide (LHM). This electrolysis step can be used for the initial production of LHM or for recovering the LHM from recycling LIBs. In either case sulphuric acid is a by-product of the electrolysis process and it can then be recycled for dissolution of black mass in battery recycling processes or for e.g. SX regeneration. In both cases the incorporation of electrolysis in the flowsheet eliminates effluent streams.

This presentation will outline the product quality and environmental benefits of electrolysis applied as part of a battery recycling flowsheet. It will outline the approach to electrolyser scale-up and present test and performance data from industrial-scale application.

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The Efficiency Improvement of Electrodeposition of High-Purity Zn by a Proper Electrolyte Solution Preparation from Spent Pickling Liquor by Anion-Exchange Separation
Authors: Zakiyya Hanna , Kekesi Tamas
Published: February 2024

A better procedure for recovering high-purity Zn from the SPL solution has been devised. To provide a suitable electrolyte for the efficient cathodic deposition of high-purity Zn, complete anion-exchange purification had been done by chromatographic technique. The process was then continued by galvanostatic electrodeposition to determine the efficiencies. As the SPL needs to be neutralized before any attempts of Zn electrodeposition, NaCl may provide the required source of Cl- ions for complex formation. The equilibrium studies of the anion-exchange distribution in such solutions showed similar tendencies to those already known in HCl media. The anion-exchange chromatographic separation was devised – with the finer tuning of the parameters – according to the equilibrium result, but other physical parameters were also examined for improving the efficiency of separation and the recovery of Zn. The devised anion-exchange separation in chloride media can purify the SPL, containing Zn as the valuable component and higher concentrations of Fe as the main impurity. The most important impurities (Fe, Mn, Ni, Al and Co) can be efficiently separated in a dissolved state. At the same time, Zn is sorbed in the strongly basic anion[1]exchange resin at a moderate Cl- ion concentration (~ 2 M). Stirring with Fe chips provides a reduction of iron to the Fe(II) state. The remaining problem is minor copper contamination in the same effluent fraction as Zn, which however can be eliminated by a simple additional step of cementation or directly by pre-electrolysis.