Lithium-ion Battery Manufacturing Research Articles

Effect of the Etching Profile of a Si Substrate on the Capacitive Characteristics of Three-Dimensional Solid-State Lithium-Ion Batteries

Along with the soaring demands for all-solid-state thin-film lithium-ion batteries, the problem of their energy density rise becomes very acute. The solution to this problem can be found in development of 3D batteries. The present work deals with the development of a technology for a 3D solid-state lithium-ion battery (3D SSLIB) manufacturing by plasma-chemical etching and magnetron sputtering technique. The results on testing of experimental samples of 3D SSLIB are presented. It was found that submicron-scale steps appearing on the surface of a 3D structure formed on Si substrate by the Bosch process radically change the crystal structure of the upper functional layers. Such changes can lead to disruption of the layers’ continuity, especially that of the down conductors. It is shown that surface polishing by liquid etching of the SiO2 layer and silicon reoxidation leads to surface smoothing, the replacement of the dendrite structure of functional layers by a block structure, and a significant improvement in the capacitive characteristics of the battery.

The role of structural defects in commercial lithium-ion batteries

The manufacturing of commercial lithium-ion batteries (LIBs) involves a number of sophisticated production processes. Various cell defects can be induced, and, depending on their structural and chemical characteristics, they could lead to acute failure and/or chronic degradation. Although tremendous efforts have been devoted to develop a robust quality control (QC) procedure, the functional role of the cell defects is not well understood. Here, we address this question through a systematic experimental study of commercial 18650-type LIBs that have failed the QC inspection due to a self-discharging effect. We identify and recover the defective regions from the cell and conduct a comprehensive investigation from the chemical, structural, and morphological perspectives. Our results reveal how the structural defects affect the cell performance, which is highly important to industry-scale battery production.

Laser structuring of graphite anodes and NMC cathodes – Proportionate influence on electrode characteristics and cell performance

For this study, microscopic diffusion channels were introduced into graphite anodes and NMC622 cathodes through short-pulsed laser radiation. The impact on the performance of coin cells comprising anodes and cathodes in pristine and structured conditions, respectively, was investigated in a discharge rate test. At high rates (1 C – 3 C), particularly cells with laser-structured anodes showed a significant increase in capacity retention of up to 10 % in comparison to cells with pristine anodes. Characteristic features in the incremental capacities indicated cell polarization and diffusion inhibition as the rate-limiting mechanisms at high discharge rates and revealed differences in the dominating deintercalation stages between the cell configurations. Fitting an equivalent circuit model to the impedance spectra of symmetric cells showed a reduction of the ionic resistances by approx. 45 % for the anodes and approx. 21 % for the cathodes through laser structuring. A similar behavior was observed for the MacMullin numbers and effective tortuosities of the electrodes. In conclusion, laser structuring offers a particular potential to overcome the diffusion-limiting characteristics of the graphite anodes. The insights into the proportionate impact of anode or cathode structuring are of high value for the design and manufacturing of future lithium-ion batteries.

In Situ Ultrasound Acoustic Measurement of the Lithium-Ion Battery Electrode Drying Process.

The electrode drying process is a crucial step in the manufacturing of lithium-ion batteries and can significantly affect the performance of an electrode once stacked in a cell. High drying rates may induce binder migration, which is largely governed by the temperature. Additionally, elevated drying rates will result in a heterogeneous distribution of the soluble and dispersed binder throughout the electrode, potentially accumulating at the surface. The optimized drying rate during the electrode manufacturing process will promote balanced homogeneous binder distribution throughout the electrode film; however, there is a need to develop more informative in situ metrologies to better understand the dynamics of the drying process. Here, ultrasound acoustic-based techniques were developed as an in situ tool to study the electrode drying process using NMC622-based cathodes and graphite-based anodes. The drying dynamic evolution for cathodes dried at 40 and 60 °C and anodes dried at 60 °C were investigated, with the attenuation of the reflective acoustic signals used to indicate the evolution of the physical properties of the electrode-coating film. The drying-induced acoustic signal shifts were discussed critically and correlated to the reported three-stage drying mechanism, offering a new mode for investigating the dynamic drying process. Ultrasound acoustic-based measurements have been successfully shown to be a novel in situ metrology to acquire dynamic drying profiles of lithium-ion battery electrodes. The findings would potentially fulfil the research gaps between acquiring dynamic data continuously for a drying mechanism study and the existing research metrology, as most of the published drying mechanism research studies are based on simulated drying processes. It shows great potential for further development and understanding of the drying process to achieve a more controllable electrode manufacturing process.

Polypeptide-based batteries toward sustainable and cyclic manufacturing

Polypeptide-based batteries toward sustainable and cyclic manufacturing

Discrete Element Method Simulation of Electrode Calendering and Its Impact on Electrochemical Performance

Lithium-ion battery (LIB) manufacturing optimization is crucial to reduce its CO2 fingerprint and cost, while improving their electrochemical performance. The latter is particularly challenging, due to the several parameters involved in LIB manufacturing and in their non-linear relationships. The aim of the ERC founded ARTISTIC project1,2 is to develop computational tools able to capture the effect of the manufacturing process on final electrode’s properties through multiscale modelling3–8 and machine learning (ML).9,10 We present here11,12 our latest work, applying discrete 3D (x,y,z) and continuum 4D (x,y,z and time) models to capture the effect of calendaring on LiNi0.33Mn0.33Co0.33O2–based cathodes. Our methodology is based on an experimentally validated Discrete Element Method model, which considers explicitly both active material (AM) and carbon-binder domain (CBD). The latter introduces important novelties respect the state of the art, such as: (i) the utilization of un-calendered electrode mesostructures resulting from experimentally validated simulations of the previous fabrication steps (slurry formulation and drying) in which the spatial distribution and interactions between AM and CBD particles are considered explicitly.3–5 (ii) the model validation through simultaneous comparison of experimental and simulated micro-indentation and porosity vs. calendering pressure curves. The resulting calendered electrodes were analyzed in terms of pore size distribution, tortuosity and particles arrangement. In addition, the evolution of the electrodes’ macroscopic electrochemical behavior (galvanostatic discharge curve and electrochemical impedance spectroscopy) upon the degree of calendering was discussed, offering added insights into the links between calendering pressure, electrode mesostructure and its electrochemical performance. References (1) https://www.u-picardie.fr/erc-artistic/.(2) https://www.u-picardie.fr/erc-artistic/computational-portal/.(3) Ngandjong, A. C.; Rucci, A.; Maiza, M.; Shukla, G.; Vazquez-Arenas, J.; Franco, A. A. Multiscale Simulation Platform Linking Lithium Ion Battery Electrode Fabrication Process with Performance at the Cell Level. J. Phys. Chem. Lett. 2017, 8 (23), 5966–5972. https://doi.org/10.1021/acs.jpclett.7b02647.(4) Rucci, A.; Ngandjong, A. C.; Primo, E. N.; Maiza, M.; Franco, A. A. Tracking Variabilities in the Simulation of Lithium Ion Battery Electrode Fabrication and Its Impact on Electrochemical Performance. Electrochim. Acta 2019, 312, 168–178. https://doi.org/https://doi.org/10.1016/j.electacta.2019.04.110.(5) Lombardo, T.; Hoock, J.; Primo, E.; Ngandjong, C.; Duquesnoy, M.; Franco, A. A. Accelerated Optimization Methods for Force-Field Parametrization in Battery Electrode Manufacturing Modeling. Batter. Supercaps 2020. https://doi.org/10.1002/batt.202000049.(6) Chouchane, M.; Rucci, A.; Lombardo, T.; Ngandjong C., A.; Franco, A. A. Lithium Ion Battery Electrodes Predicted from Manufacturing Simulations: Assessing the Impact of the Carbon-Binder Spatial Location on the Electrochemical Performance. J. Power Sources 2019. https://doi.org/https://doi.org/10.1016/j.jpowsour.2019.227285.(7) Chouchane, M.; Primo, E. N.; Franco, A. A. Mesoscale Effects in the Extraction of the Solid-State Lithium Diffusion Coefficient Values of Battery Active Materials: Physical Insights from 3D Modeling. J. Phys. Chem. Lett. 2020, 11 (7), 2775–2780. https://doi.org/10.1021/acs.jpclett.0c00517.(8) Shodiev, A.; Primo, E. N.; Chouchane, M.; Lombardo, T.; Ngandjong, A. C.; Rucci, A.; Franco, A. A. 4D-Resolved Physical Model for Electrochemical Impedance Spectroscopy of Li(Ni1-x-YMnxCoy)O2-Based Cathodes in Symmetric Cells: Consequences in Tortuosity Calculations. J. Power Sources 2020, 454, 227871. https://doi.org/10.1016/j.jpowsour.2020.227871.(9) Cunha, R. P.; Lombardo, T.; Primo, E. N.; Franco, A. A. Artificial Intelligence Investigation of NMC Cathode Manufacturing Parameters Interdependencies. Batter. Supercaps 2020, 3 (1), 60–67. https://doi.org/doi:10.1002/batt.201900135.(10) Duquesnoy, M.; Lombardo, T.; Chouchane, M.; Primo, E. N. Data-Driven Assessment of Electrode Calendering Process by Combining Experimental Results , in Silico Mesostructures Generation and Machine Learning. J. Power Sources 2020, 480, 229103. https://doi.org/10.1016/j.jpowsour.2020.229103.(11) Ngandjong, A.; Lombardo, T.; Primo, E.; Chouchane, M.; Shodiev, A.; Arcelus, O.; Franco, A. A. Investigating Electrode Calendering and Its Impact on Electrochemical Performance by Means of a New Discrete Element Method Model: Towards a Digital Twin of Li-Ion Battery Manufacturing. ChemRxiv 2020, 1–40.(12) Ngandjong, A.; Lombardo, T.; Primo, E.; Chouchane, M.; Shodiev, A.; Arcelus, O.; Franco, A. A. Investigating Electrode Calendering and Its Impact on Electrochemical Performance by Means of a New Discrete Element Method Model: Towards a Digital Twin of Li-Ion Battery Manufacturing. J. Power Sources 2020, accepted .

Degradation Diagnostics in Graphite-NMC Cells Under Fast SEI Formation

The formation process is the last step in the lithium ion battery manufacturing process but plays an outsize role in determining cell costs [1], [2]. A typical formation protocol consists of multiple low-rate charge-discharge cycles which can take many days to complete. During formation, the solid-electrolyte interface (SEI) is created through irreversible lithium reduction reactions with the electrolyte at the negative electrode surface. Formation protocols are difficult to optimize in part because their impact to long term cell lifetime and safety remain under debate. For example, while some authors have reported that the voltage window and charging rate during formation could impact cycle life[3], [4], others have found that formation protocols as fast as 14 hours[5] or ones causing lithium plating[6] have little to no impact on cycle life. The current evidence suggests that there remain opportunities to optimize the formation protocol for a given cell chemistry and design. However, finding an optimal formation protocol will require a more detailed understanding of the long-term impact on cell degradation and with consideration for cell safety.In this study, we design a test sequence and identify diagnostic signals to elucidate the impact of a fast formation protocol[5] on the long-term cycle life behavior of NMC/graphite cells. The study consists of 40 identical pouch cells built in-house at the University of Michigan Battery Lab. Half of the cells were subjected to the fast formation protocol and the remaining cells used a baseline formation protocol. Each set of cells were further split into two groups to be cycled at room temperature and inside a temperature-controlled oven at 45°C. The aging test consists of 1C charge-discharge cycles between 3.0V and 4.2V. Periodic reference performance tests were inserted as part of the aging test to provide additional diagnostic signals, including cell internal resistances as a function of state of charge and low-rate voltage curves for differential capacity analysis. Cells were stopped after discharge capacities were measured to be below 50%. At the end of the test, the degree of cell swelling was measured.The results showed that the cells with fast formation had a longer cycle life compared to control, but the same cells also showed higher cell-to-cell variability towards the end of life. Nearly all cells with fast formation showed moderate to severe swelling when cycled at 45°C, in contrast to the cells with baseline formation which showed little to no volume change. Taken together, these results suggest that it is possible for a fast formation protocol to yield similar or better cycle life but still potentially compromise the safety of the cell through increased gas generation rates. We also monitored the cycle life of several cells that showed a non-monotonic current behavior during formation attributable to a reversible lithium plating process. The cycle life and resistance growth of these cells fell within the expected range of values after considering cell-to-cell variation, suggesting that the presence of transient lithium plating during formation does not have a long-term impact to cell lifetime. Finally, in exploring the diagnostic signals, we identify two beginning-of-life signals that showed positive correlation with the maximum cycle count and cell resistance measured at the end-of-life: (1) the cell resistance measured at low states of charge, and (2) the voltage decay during a rest step inserted at the end of the last formation charge cycle. This last finding revitalizes the possibility of designing cell lifetime predictors using simple metrics measured at the beginning of life.[1] D. L. Wood, J. Li, and C. Daniel, J. Power Sources, vol. 275, pp. 234–242, 2015[2] K. Kuhlmann, S. Wolf, C. Pieper, G. Xu, and J. Ahmad, Bost. Consult. Gr., pp. 1–22, 2018[3] T. S. Pathan, M. Rashid, M. Walker, W. D. Widanage, and E. Kendrick, J. Phys. Energy, vol. 1, no. 4, p. 044003, 2019[4] C. Mao et al., J. Power Sources, vol. 402, no. July, pp. 107–115, 2018[5] D. L. Wood, J. Li, and S. J. An, Joule, vol. 3, no. 12, pp. 2884–2888, 2019[6] M. Ryan et al., J. Power Sources, vol. 484, pp. 0–7, 2021 Figure 1

Recovery of lithium from leach solutions of battery waste using direct solvent extraction with TBP and FeCl3

Although societal interest in lithium has grown due to its increased demand for manufacturing of lithium ion batteries (LIBs), recent research studies about LIB recycling with solvent extraction did not focus on Li recovery and Li remained in the raffinate contaminated with impurities. In this research presented direct Li recovery from LIB waste leachate prior to Ni and Co is a novel and promising approach.The applied SX system (tributyl phosphate (TBP) as extractant and iron(III) chloride (FeCl3) as co-extractant in kerosene) is known from Li separation from natural brines. Batch equilibrium experiments at room temperature were conducted with preloaded organic phase (NaCl and FeCl3, TBP (80% (v/v)) and kerosene (20% (v/v)) and synthetic aqueous LIB waste leachate solution (1.3–1.5 g L−1 Al, 14.2–17.8 g L−1 Co, 1.9–2.2 g L−1 Cu, 0.7–0.8 g L−1 Fe, 2.4–2.7 g L−1 Li, 1.9–2.1 g L−1 Mn, 1.8–2.0 g L−1 Ni, E = 603 mV Ag/AgCl). Loading with emphasis on the competitive extraction between Li and H+, substitution of MgCl2 as chloride source and variation of the phase ratios as well as scrubbing and stripping are investigated in this research.Lithium was selectively separated over divalent LIB metals (Mn, Cu, Co, Ni) and Al(III) from a multicomponent mixture, and the extraction ability of the system is H+ > Li+ > > LIB metals. Aiming for maximum Li extraction initial concentration of H+ was chosen to be 0.1 M. Substitution of MgCl2, used in the brine systems, by AlCl3 as chloride source promoted Li extraction (E(Li) = 87.7% for R(O/A) = 1) due to its strong salting out effect. This resulted in enhanced separation factors (β(Ni) = 2825 and β(Co) = 854 for R(O/A) = 1). Loaded organic phase was purified using 1 M LiCl +2 M AlCl3 scrubbing solution prior stripping. Stripping with 6 M HCl in single-stage at R(O/A) = 5 resulted in stripping liquor containing 12.26 g L−1, 0.02 g L−1, 0.04 g L−1, and 0.04 g L−1 of Li, Mn, Co and Cu, respectively.

Insight on electrolyte infiltration of lithium ion battery electrodes by means of a new three-dimensional-resolved lattice Boltzmann model

Electrolyte filling takes place between sealing and formation in Lithium Ion Battery (LIB) manufacturing process. This step is crucial as it is directly linked to LIB quality and affects the subsequent time consuming electrolyte wetting process. Although having fast, homogeneous and complete wetting is of paramount importance, this process has not been sufficiently examined and fully understood. For instance, experimentally available data is insufficient to fully capture the complex interplay upon filling between electrolyte and air inside the porous electrode. We report here for the first time a 3D-resolved Lattice Boltzmann Method (LBM) model able to simulate electrolyte filling upon applied pressure of LIB porous electrodes obtained both from experiments (micro X-ray tomography) and computations (stochastic generation, simulation of the manufacturing process using Coarse Grained Molecular Dynamics and Discrete Element Method). The model allows obtaining advanced insights about the impact of the electrode mesostructures on the speed of electrolyte impregnation and wetting, highlighting the importance of porosity, pore size distribution and pores interconnectivity on the filling dynamics. Furthermore, we identify scenarios where volumes with trapped air (dead zones) appear and evaluate the impact of those on the electrochemical behavior of the electrodes.

A Novel Cavity-Enhanced Polyethylene/Nanostructured-Alumina Separator with Long Cycle Life and High Rate Capability for Advanced Lithium-Ion Batteries

Traditional polyolefin separators cannot meet the increasing requirements of lithium-ion batteries (LIBs) for the high power density, high energy density, and high safety that the secondary battery market has expanded to electric vehicles. It is still a great challenge to reduce ion-transport resistance, promote thermal stability, and improve the mechanical properties of polymer-based separators. Herein, a novel composite separator with enhanced conductivity, good mechanical strength, and high thermo-dimensional stability is designed and demonstrated for the application of advanced LIBs. The flexible multiarm structure of nanostructured alumina nanoparticles (NPs) greatly promotes the orientation of high density polyethylene (HDPE) during the polymer processing, significantly enhancing the pore cavity during the separator formation process. The porosity, pore size distribution, thermo-dimensional stability, and mechanical strength of the resultant composite separator are significantly improved, leading to long cycle life and high rate capability. The orientation/crystallization development of HDPE by the introduction of alumina NPs has been examined via microstructure analysis. This demonstration not only shows the high impact on the separator manufacturing of LIBs with a high power density and high safety but also creates a new method in controlling the orientation and cavity design of polyolefin materials.

A facile and low-cost Al2O3 coating as an artificial solid electrolyte interphase layer on graphite/silicon composites for lithium-ion batteries

Graphite/silicon (G/Si) composites are considered as possible alternative anode materials to commercial graphite anodes. However, the unstable solid electrolyte interphase (SEI) on G/Si particles results in rapid capacity decay, impeding practical applications. Herein, a facile and low-cost Al2O3 coating was developed to fabricate stable artificial SEI layers on G/Si composites. The amorphous Al2O3 coating with a thickness of 10–15 nm was synthesized by a simple sol–gel method followed by high-temperature annealing. The Al2O3 coated G/Si anode delivers an initial discharge capacity of 540 mAh g−1 at 25 °C and has improved Coulombic efficiency and cycling stability. After 100 cycles, the capacity retention is 76.4%, much higher than the 56.4% of the uncoated anode. Furthermore, the Al2O3 coating was found to be more effective at improving the stability of G/Si at a higher temperature (55 °C). This was explained by the Al2O3 coating suppressing the growth of SEI on Si/G and thus reducing the charge transfer resistance at the G/Si–electrolyte interface. It is expected that the Al2O3 coating prepared by the sol–gel process can be applied to other Si-based anodes in the manufacture of practical high-performance lithium-ion batteries.

Water-based manufacturing of lithium ion battery for life cycle impact mitigation

Water-based manufacturing processes are under development for greener manufacturing of lithium ion batteries but their environmental impacts are unclear with new introduced materials and a large consumption of deionized water. We report a life cycle assessment (LCA) study on the water-based manufacturing of the most popular NMC-graphite battery pack configured with 57 kWh capacity. A life cycle model has been developed based on experimental and mathematical studies of the water-based manufacturing processes. Per kg battery pack produced, the water-based manufacturing can reduce the manufacturing energy by 43% and lower the cradle-to-gate life cycle impacts by 0.6%∼88% over conventional battery manufacturing.

In-Situ Ultrasound Acoustic Measurement of the Lithium-Ion Battery Electrode Drying Process

The electrode drying process is a crucial step in the manufacture of lithium-ion batteries and can significantly affect the performance of an electrode once stacked in a cell. However, there is a need to develop more informative in-situ metrologies to better understand the dynamics of the drying process. Here, ultrasound acoustic based technique has been developed as an in-situ tool to study the electrode drying process using NMC622-based cathodes and graphite-based anodes. The drying dynamic evolution for cathodes dried at 40 and 60 °C, and anodes dried at 60 °C were investigated, with the attenuation of the reflective acoustic signals used to indicate the evolution physical properties of the electrode coating film. The drying-induced acoustic signal shifts were discussed critically and correlated to the reported three-stage drying mechanism, which offering a new mode to investigate the dynamic drying process. Ultrasound acoustic based measurement has been successfully shown to be a novel in-situ metrology to acquire dynamic drying profiles. The findings would potentially fulfil the research gaps between acquiring dynamic data continuously for drying mechanism study and existing research metrology. It shows the great potential to be further developed and understand the drying process to achieve a more controllable electrode manufacturing process.

DEM Simulations of the Calendering Process: Parameterization of the Electrode Material of Lithium-Ion Batteries

During the manufacturing of lithium-ion batteries, calendering is the final step in electrode production. It is a crucial process, which significantly influences the mechanical and electrochemical properties of the electrodes and is decisive in defining the volumetric energy density of lithium-ion batteries. To predict the calendering parameters, a particle model using the discrete element method (DEM) is calibrated based on a parameterization framework. The parameterization methodology for calibration applied in this paper is universally valid, applicable to various material systems and based on a one-factor-at-a-time variation to reduce the number of parameters. With this reduced parameter set, an automatic parametrization using optimization algorithms is feasible.

(Keynote) Facile Fabrication of High-Performance Lib Anode and Cathode Materials on Al and Ti By Smart Anodization and Hybrid Electrodeposition

Aluminum and titanium materials are well known as typical light metals which are widely applied to versatile products for their high corrosion resistance, conductive and decorative properties, etc. Recently, aluminum and titanium materials are paid extensive attention to battery industry, using as current collectors or electrode materials. Lithium-ion batteries (LIBs) are known as important power sources in many electric/electronic products such as cellular phones, digital cameras, portable computers, as well as electric vehicles (EVs) and hybrid electric vehicles (HEVs). To meet the ever-expanding needs for lithium-ion battery industry, it is an urgent task to develop new technologies for producing LIB materials with optimal performance-safety balance, and to substituting conventional sintering-casting process by cost-effective process in manufacture of LIBs. In this study, we report three new processes to fabricate cathode and anode materials for LIBs as below. Fabrication of Li-V-Mn-Ni-O composite films on Al by a hybrid electrodeposition for LIB Cathodes Fig.1a shows a cross-sectional scheme of Li-V-Mn-Ni-O composite films on Al foils. Different from the conventional sintering methods for producing LiCoO2-based LIB cathodes, we proposed a novel hybrid electrodeposition to fabricate Li-V-Mn-Ni-O composite films directly on Al, which is expected to increase the working potential with Li ions above 4 V vs. Li+/Li and to decrease the cost of active materials. The composite films were obtained by a cathodic electrodeposition in ethanol-water bath containing V5+、Ni2+, Mn2+, and Li+ ions. Before electrodeposition, an electro-etching pretreatment was adopted to enhance the adhesion between the Al substrate and the electrodeposits. It is found that the resultant composite films after annealing consists of V2O5, Li2MnO4, NiOOH, and metallic Li components. The cyclic voltammetric measurements detected three peaks at 3.2, 4.01, and 4.33 V vs. Li+/Li, which can be ascribed to the Li extraction reactions from the substance mentioned above, indicating the composite films worked as active materials as LIB cathodes. Formation of nanoporous TiO2-TiO-TiN composite films on Ti by a smart anodization for LIB anodes Nanoporous anodic TiO2 films are considered as promising LIB anode materials to solve the safe issue caused by lithium electrodeposition during charge/discharge process as use C-base anodes conventionally. However, the poor conductivity and low theoretic capacity of TiO2 materials are big concerns for practical uses for high density LIBs. Here, we formed successfully nanoporous TiO2-TiO-TiN composite films on Ti foils by a smart anodization in aqueous NO3 –-based solutions and found that the inclusion of conductive TiN component in TiO2 matrix film improved the electronic conductivity effectively (Fig.1.b). The TiO2-TiO-TiN composite films after being heated at 150–500 ºC can be used as binder-conductive reagent free LIB anodes and exhibited higher capacity than ordinary TiO2 films. Fabrication of TiO2-TiN/M-MOx (M = Sn, Mo) composite films on Ti by Hybrid electrolytic process In order to increase the capacity of anodic TiO2-TiN films, we conducted various electrodeposition of Sn-based and Mo-based materials with high theoretic capacities into the anodic TiO2-TiN matrix films, as shown in Fig.1c. The inclusion of highly conductive TiN component in TiO2 matrix film during anodization endows the necessary electronic conductivity for the successive cathodic hybrid electrodeposition of various active materials with high theoretic capacities. The one approach is to fill Sn and SnO2 nanoparticles into TiO2-TiN matrix films by using an acidic plating bath containing different Sn ions. This not only increased the areal specific capacity in 4–9 times compared to the anodic TiO2-TiN films, but also improved the conductivity of the composite films. Another approach is to fill Mo-based materials from a molybdate solution. It is found by XPS analysis that the resultant Mo-based deposits composed of molybdate oxides (MoO2-MoO3) and molybdate nitrides (Mo2N-MoN). The electrodeposition of Mo-based materials into TiO2-TiN films improved the conductivity of the composite films significantly due to the high conductive components of molybdate nitrides. As a result, TiO2-TiN/MoOx-MoyN composite films exhibited around 5 times higher discharge capacity than the TiO2-TiN films and excellent cycling performance with a retention of 97%, indicating a promising anode material with high power density and high safety for LIBs. Figure 1

The Effect of Wavelength on the Laser Structuring of Graphite-Based Anodes for Lithium-Ion Batteries

The use of laser-based processes in battery manufacturing is becoming more and more common [1]. The majority of the research and applications in this field focus on pulsed nanosecond lasers, primarily due to a lower capital cost. There are potential applications for shorter pulse length lasers in battery manufacture due to the change in ablation regime, from a thermal to a cold ablation process that results in significantly less damage to the structure of the batteryIn this research, a femtosecond laser has been used to cut and structure graphite anodes for coin cell batteries. The lasers fundamental emission wavelength is in the infra-red region at 1029nm and it has a maximum average power of 40W. The same laser is also capable of operating at the second (515nm) and third (343nm) harmonics, with a maximum average power of 20W and 10W respectively. This allowed for a direct comparison of how modifying the wavelength of the laser affects the structuring of the anode material, in this instance a graphite coating with an SBR-PVDF binder, with a specific focus on any amorphisation of the crystalline structure which may occur during the structuring process. A further comparison of optimised processes at each wavelength, with respect to time, are presented.A reduction in amorphization at all wavelengths was observed for both cutting and structuring graphitic material when compared to longer pulse length lasers. These findings could allow the use of lasers in creating 3D structured electrodes without the loss in performance of the final cell that is observed when using nanosecond lasers [3]. It has been shown that the creation of structures in the electrode material of a lithium ion battery can improve a cells stability under higher C-rates due to an improvement in ion diffusion kinetics by increasing the surface area of the active material [4]. As well as this, structuring can aid in the wetting of electrolytes into active materials, this is especially prevalent when looking into thick film electrodes such as those over 50µm [5].It has been shown that the specific capacity of a cell with a thick-film NMC electrode drops with increasing thickness, even for C rates as low as C/5 [1]. Laser structuring helps alleviate the problem by increasing the surface area of the active material and while this is done by removing some of said material, it can still lead to an increase in the effective capacity of a constructed cell. While some studies have investigated the machining of high aspect ratio micro-channels, the effect of wavelength on laser structuring of anodes with ultrafast lasers has not been thoroughly investigated until now.With more information on how various laser based structuring techniques effects the electrode material further improvements can be made not only to the individual performance of cells but the manufacturing process of lithium ion batteries in general.[1] W. Pfleging, “A review of laser electrode processing for development and manufacturing of lithium-ion batteries,” Nanophotonics, vol. 7, no. 3, pp. 549–573, Feb. 2018, doi: 10.1515/nanoph-2017-0044.[2] T. Jansen, M. W. Kandula, S. Hartwig, L. Hoffmann, W. Haselrieder, and K. Dilger, “Influence of Laser-Generated Cutting Edges on the Electrical Performance of Large Lithium-Ion Pouch Cells,” Batteries, vol. 5, no. 4, p. 73, Dec. 2019, doi: 10.3390/batteries5040073.[3] M. Mangang, H. J. Seifert, and W. Pfleging, “Influence of laser pulse duration on the electrochemical performance of laser structured LiFePO 4 composite electrodes,” J. Power Sources, vol. 304, pp. 24–32, 2016, doi: 10.1016/j.jpowsour.2015.10.086.[4] P. Smyrek, Y. Zheng, H. J. Seifert, and W. Pfleging, “Post-mortem characterization of fs laser-generated micro-pillars in Li(Ni 1/3 Mn 1/3 Co 1/3 )O 2 electrodes by laser-induced breakdown spectroscopy,” 2016, no. March 2016, p. 97361C, doi: 10.1117/12.2210815.[5] W. Pfleging and J. Pröll, “A new approach for rapid electrolyte wetting in tape cast electrodes for lithium-ion batteries,” J. Mater. Chem. A, vol. 2, no. 36, pp. 14918–14926, 2014, doi: 10.1039/C4TA02353F.

Study of Lithium Ion Battery Manufacturing Process Using Quasi-Solid Electrolyte Sheet

IntroductionIn conventional lithium ion battery (LIB), organic electrolyte exhibiting a high volatility and flammability is applied. Therefore, energy storage system with the LIB possesses a lot of auxiliary components for ensuring its safety, which do not directory contribute to electricity storage and lower its volumetric and gravitic energy density. Hence, the high safety of the LIB is the key to increase the volume energy density and the LIBs using several types of electrolytes such as a gel [1], a solid-state [2] and a quasi-solid-state [3] have been investigated. In particular, 100 Wh-class LIB using quasi-solid-state electrolyte (QSE) as a highly safe electrolyte demonstrated incombustibility in the nail-penetration test [3]. QSE is prepared by pseudo solidifying of solvate ionic liquid which consists of an equimolar mixture of lithium salt and tetraglyme(G4) at oxide particle surfaces. In this research, LIB manufacturing process using QSE that is highly compatible with conventional manufacturing processes was examined.Experiment Solvate ionic liquid, Li(G4)TFSA, was prepared by mixing an equimolar of lithium bis(trifluoromethanesulfonyl)amide, LiTFSA, and G4 [4]. Li(G4)TFSA, silica nano particle, and fluorine-based binder were mixed in a prescribed ratio. QSE sheet was prepared by coating and drying the mixture on the substrate. Li(G4)TFSA has a refractory characteristics. To prepare electrode containing Li(G4)TFSA, the electrode slurry including Li(G4)TFSA was coated and dried on the current collector foil. Li(Ni,Co,Mn)O2 pseudo-ternary oxide and graphite were used as the active material of the positive and negative electrode, respectively. The volatile mixed solution of propylene carbonate (PC) as low viscosity solvent [1] and vinylene carbonate (VC) for suppress the SEI formation was directly coated on the surface of the pressed electrode (coating method). In addition, QSE sheets and the electrode were stacked and heat-sealed by the four sides in order to suppress the volatilization of additive mixed solution (edge sealing structure). NMR analysis of the electrolyte components extracted by immersing in deuterated chloroform solvent after standing under manufacturing environment ( dew point : about -35℃) at various time ( for 0 to 24 hours) was carried out to examine the volatile behavior of PC and VC. Moreover, charge-discharge performance of LIB using QSE was evaluated by a model cell (diameter of electrode was less than 18 mm).Result and discussion In the previous research [5], the same charge-discharge performance as one of the conventional injection method was obtained by the coating method in which a small amount (5ml/cm2) of PC and VC mixed solution was directly coated on the electrode. It indicated that the injection process which had been a bottleneck in the LIB manufacturing process could be omitted. In order to apply the coating method to the mass production process, it is necessary to suppress concentration fluctuations of PC and VC by volatilization. In particular, the vapor pressure of VC is higher than the other electrolyte components. VC is an important component for SEI formation at the negative electrode interface. Concentration fluctuation of VC can be a factor for lowering LIB performance. Therefore, the edge sealing structure as shown in Figure 1 was prepared to seal the additive mixed solution. Figure 2 shows the relation between VC residual ratio and time. In the reference sample without applying the edge sealing structure, VC vapored quickly and the residual ratio decreased to about 60% after 30 minutes. On the other hands, VC residual ratio remained 93% even after 24 hours in the edge sealing structure, which proves the edge sealing can suppress VC volatilization significantly. Figure 3 shows the charge-discharge performance of LIB using QSE with the edge sealing structure. The charge-discharge performance of 24hours after coating the additive mixed solution did not deteriorate compared to the performance of immediately after coating. In this presentation, details of the manufacturing process using the coating method and the edge sealing structure will be discussed.

Miscibility of Poly(Methyl Methacrylate) and Poly(Vinylidene Fluoride) Examined by Thermally Stimulated Depolarization Current and Dielectric Relaxation Spectroscopy

Samples of poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVDF) and melt blended PMMA/PVDF with weight ratios 4/1 and 3/2 were characterized by thermally stimulated depolarization currents (TSDC) in the temperature interval 123-303 K and by dielectric relaxation spectroscopy (DRS) in the frequency window 10−2 − 106 Hz in the temperature interval 153-423 K. The TSDC thermograms and DRS profiles of the samples showed the two types of conducnivity – non-cooperative and cooperative. The experimental DRS data in the vicinity of the glass transition temperature, Tg, were quantitatively fitted to the Havriliak-Negami function and values of the maximum relaxation time were fitted to the Vogel-Tammann-Fulcher equation. Higher values of the strength index D, of the dielectric relaxation strength Δε and of the σ ac conductivity for the binary blends were considered as experimental evidence for nanoscale composition heterogeneities originating from strong specific interactions between the PMMA and PVDF. Therefore, we suggest the PMMA/PVDF blends will be usefull as effective materials for the manufacture of lithium-ion batteries, electrostatic capacitors with superior energy storage performance, polymer composite electrolytes for solar cells, etc.

Research and Application of Information Model of a Lithium Ion Battery Intelligent Manufacturing Workshop Based on OPC UA

Automation equipment with different functions from different manufacturers is common in lithium ion battery manufacturing workshops, which is manifested as heterogeneous data distributed at different network levels at the information level. The interconnection between a workshop system and equipment is the basis for realizing manufacturing informatization and intelligence, and is a core problem of intelligent manufacturing workshop integration. The key to solve this problem is to establish a standardized and consistent information model. Aiming at the problem of information interconnection, this paper established an information model of the intelligent manufacturing workshop of lithium ion batteries based on the analysis of the architecture, functional categories, and information interaction of the intelligent manufacturing workshop. Then, by clarifying the attribute set, component set, and the information objects contained in each information model, the hierarchical architecture of the information model was constructed. Then, the rules that map the information model in to the OLE for Process Control Unified Architecture (OPC UA) address space is established. The approach for implementing data storage and interaction of the information model based on the OPC UA server/client are also discussed. Finally, taking the soft-pack battery manufacturing workshop as an example, the information model is applied to realize the interconnection and interoperability of production management data, material management data, equipment management data, and quality management data among various levels of the workshop, which verifies the feasibility of the proposed information model.

Potential impact of the end-of-life batteries recycling of electric vehicles on lithium demand in China: 2010–2050

China is expected to realise the complete electrification of traditional internal combustion engine vehicles (ICEVs) by 2050. The rapid development of electric vehicles (EVs) has led to the continuous growth of traction lithium-ion battery (LIB) demand, leading to an increase in demand for specific lithium materials. Therefore, end-of-life (EoL) LIB recycling will largely determine the future lithium availability in China. However, the contribution of recovered lithium to lithium availability is unclear, as the possibility of recovering lithium for reuse in traction LIBs manufacturing is uncertain. To analyse the influence of recovered lithium quality on future lithium availability, we evaluated the potential impact of EoL LIB recycling on lithium demand in China. The results indicated that if new LIB manufacturing cannot use the recovered lithium; the secondary resources would soon exceed the needs of the basic demand (BD) field. In the optimistic scenario, when a LiS battery is used, the oversupply could reach 2.33 Mt by 2050 with a recovery rate of 80%, which is equivalent to 44.05% of China's current lithium reserves of 5.29 Mt. Additionally, when the NCM-G battery is used, the total lithium demand would reach approximately 5.67 Mt in 2031, exceeding China's current lithium reserves. In contrast, if the recovered lithium could be reused in new LIB manufacturing, regardless of the type of LIBs used, the recovered lithium would meet approximately 60% (pessimistic scenario), 53% (neutral scenario), and 49% (optimistic scenario) of the lithium demand for LIBs produced with a recovery rate of 80% by 2050. Consequently, the quality of recovered lithium is very important for its reuse, and it is necessary to develop closed-loop recycling with economic benefits vigorously by improving the quality of recovered lithium. Moreover, much work should be done in recycling infrastructure and industrial policies to promote EoL battery recycling.