From Lab to Manufacturing Line: Guidelines for the Development and Upscaling of Aqueous Processed NMC622 Electrodes

Lithium-ion batteries (LIBs) have facilitated the transition to a more sustainable energy model. Paradoxically, current high energy cathodes are industrially processed using organic solvents, which are deleterious for the environment. In this work, LiNi0.6Mn0.2Co0.2O2 (NMC622) high-energy cathode electrode was prepared at laboratory scale following a more environmentally friendly aqueous route. Several steps in the preparation of the electrodes (such as the drying temperature, drying air flux or pH buffering) were thoroughly optimized to enhance the quality of the water-processed electrodes. Afterwards, the recipe developed at laboratory scale was upscaled to a semi-industrial electrode coating line, to analyze the viability of the developed processing conditions into a realistic electrode manufacturing environment. The electrodes obtained were tested in full coin cells using graphite-based anodes as counter electrodes. Interestingly, the cycling performance of the cells based on water-processed electrodes was higher than that of organic-processed ones. It is evidenced that it is possible to manufacture electrodes for high energy density LIBs following environmentally friendly, cheaper, and industrially implementable electrode processing methods with no-penalty in the electrochemical performance.This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No 769929 (IMAGE) and No 814464 (Si-DRIVE)

Insights into the Electrochemical Performance of 1.8 Ah Pouch and 18650 Cylindrical NMC:LFP|Si:C Blend Li-ion Cells

Silicon has become an integral negative electrode component for lithium-ion batteries in numerous applications including electric vehicles and renewable energy sources. However, its high capacity and low cycling stability represent a significant trade-off that limits its widespread implementation in high fractions in the negative electrode. Herein, we assembled high-capacity (1.8 Ah) cells using a nanoparticulate silicon–graphite (1:7.1) blend as the negative electrode material and a $LiFePO_{4}–LiNi_{0.5}Mn_{0.3}Co_{0.2}O_{2}$ (1:1) blend as the positive electrode. Two types of cells were constructed: cylindrical 18650 and pouch cells. These cells were subjected both to calendar and cycling aging, the latter exploring different working voltage windows (2.5–3.6 V, 3.6–4.5 V, and 2.5–4.5 V). In addition, one cell was opened and characterised at its end of life by means of X-ray diffraction, scanning electron microscopy, and further electrochemical tests of the aged electrodes. Si degradation was identified as the primary cause of capacity fade of the cells. This work highlights the need to develop novel strategies to mitigate the issues associated with the excessive volumetric changes of Si

Reduction of Grain Boundary Resistance of La0.5Li0.5TiO3 by the Addition of Organic Polymers

The organic solvents that are widely used as electrolytes in lithium ion batteries present safety challenges due to their volatile and flammable nature. The replacement of liquid organic electrolytes by non-volatile and intrinsically safe ceramic solid electrolytes is an effective approach to address the safety issue. However, the high total resistance (bulk and grain boundary) of such compounds, especially at low temperatures, makes those solid electrolyte systems unpractical for many applications where high power and low temperature performance are required. The addition of small quantities of a polymer is an efficient and low cost approach to reduce the grain boundary resistance of inorganic solid electrolytes. Therefore, in this work, we study the ionic conductivity of different composites based on non-sintered lithium lanthanum titanium oxide (La0.5Li0.5TiO3) as inorganic ceramic material and organic polymers with different characteristics, added in low percentage (<15 wt.%). The proposed cheap composite solid electrolytes double the ionic conductivity of the less cost-effective sintered La0.5Li0.5TiO3.We thank the Spanish Ministry for Science and Technology (MAT2007-64486-C07-05) and CDTI (ALMAGRID of the "CERVERA Centros Tecnológicos" program, CER-20191006) for financial their support. JS, AV, SG, and FG also want to acknowledge Agencia Española de Investigación /Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the projects PID2019-106662RB-C41, C42, C43, and C44

A Post-Mortem Study of Stacked 16 Ah Graphite//LiFePO₄ Pouch Cells Cycled at 5 °C

Herein, the post-mortem study on 16 Ah graphite//LiFePO4 pouch cells is reported. Aiming to understand their failure mechanism, taking place when cycling at low temperature, the analysis of the cell components taken from different portions of the stacks and from different positions in the electrodes, is performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). Also, the recovered electrodes are used to reassemble half-cells for further cycle tests. The combination of the several techniques detects an inhomogeneous ageing of the electrodes along the stack and from the center to the edge of the electrode, most probably due to differences in the pressure experienced by the electrodes. Interestingly, XPS reveals that more electrolyte decomposition took place at the edge of the electrodes and at the outer part of the cell stack independently of the ageing conditions. Finally, the use of high cycling currents buffers the low temperature detrimental effects, resulting in longer cycle life and less inhomogeneities

GREENLION Project: Advanced Manufacturing Processes for Low Cost Greener Li-Ion Batteries

GREENLION is a Large Scale Collaborative Project within the FP7 (GC.NMP.2011-1) leading to the manufacturing of greener and cheaper Li-Ion batteries for electric vehicle applications via the use of water soluble, fluorine-free, high thermally stable binders, which would eliminate the use of VOCs and reduce the cell assembly cost. The project has 6 key objectives: (i) development of new active and inactive battery materials viable for water processes (green chemistry); (ii) development of innovative processes (coating from aqueous slurries) capable of reducing electrode production cost and avoid environmental pollution; (iii) development of new assembly procedures (including laser cutting and high temperature pre-treatment) capable of substantially reduce the time and the cost of cell fabrication; (iv) lighter battery modules with easier disassembly through eco-designed bonding techniques; (v) waste reduction, which, by making use of the watersolubility of the binder, allows the extensive recovery of the active and inactive battery materials; and (vi) development of automated process and construction of fully integrated battery module for electric vehicle applications with optimized electrodes, cells, and other ancillaries. Achievements during the first 18 months of the project, especially on materials development and water-based electrode fabri cation are reported herein

Influence of the Ambient Storage of LiNi0.8Mn0.1Co0.1O2 Powder and Electrodes on the Electrochemical Performance in Li-ion Technology

Nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) is one of the most promising Li-ion battery cathode materials and has attracted the interest of the automotive industry. Nevertheless, storage conditions can affect its properties and performance. In this work, both NMC811 powder and electrodes were storage-aged for one year under room conditions. The aged powder was used to prepare electrodes, and the performance of these two aged samples was compared with reference fresh NMC811 electrodes in full Li-ion coin cells using graphite as a negative electrode. The cells were subjected to electrochemical as well as ante- and postmortem characterization. The performance of the electrodes from aged NM811 was beyond expectations: the cycling performance was high, and the power capability was the highest among the samples analyzed. Materials characterization revealed modifications in the crystal structure and the surface layer of the NMC811 during the storage and electrode processing steps. Differences between aged and fresh electrodes were explained by the formation of a resistive layer at the surface of the former. However, the ageing of NMC811 powder was significantly mitigated during the electrode processing step. These novel results are of interest to cell manufacturers for the widespread implementation of NMC811 as a state-of-the-art cathode material in Li-ion batteries.This work was supported by European Union’s Horizon 2020 research and innovation programme [No. 814389 (SPIDER project)]; and the CDTI—Ministerio De Ciencia e Innovación’s ‘CERVERA Centros Tecnológicos’ program [CER-20191006 (ALMAGRID project)]. V.P. and T.R. also wish to thank the funding from Gobierno Vasco/Eusko Jaurlaritza (IT-1226-19)

Enabling steady graphite anode cycling with high voltage, additive-free, sulfolane-based electrolyte: Role of the binder

We demonstrate here the possibility of operating both high voltage spinel and high mass loading graphite electrodes in a 1 M LiPF6 in SL/DMC (1/1, wt/wt) electrolyte without the use of additive. A crucial point for practical graphite electrode operation is the use of the cheaper and environmentally friendly carboxymethyl cellulose (CMC)/styrene-butadiene rubber (SBR) combination instead of the PVDF-based electrodes used in most laboratory studies. With this type of anode we also show the operation of a full Li-ion cell operating at 4.5 V without any additive and show that most of the Li+ transport limitation observed in half-cells are in fact due to the Li metal counter electrode. The anode binder influence is to be considered for the development of high voltage electrolytes lacking good intrinsic SEI building properties, as the anode binder does not affect cathode performance, contrary to most additives. It opens the route for further improvement by use of SEI forming additives (molecular and salts), keeping in mind the requirement for the cathode

Adiponitrile-based electrolytes for high voltage, graphite-based Li-ion battery

Operating high voltage lithium-ion batteries (LIB) is still an obstacle due to the limited anodic stability of state-of-the-art alkyl carbonates-based electrolytes which incorporate ethylene carbonate (EC). Thus, we replace here the widely used ethylene carbonate (EC)/dimethyl carbonate (DMC) solvent formulation by adiponitrile (ADN)/DMC (1/1, wt./wt.), to enable room temperature electrolyte formulations with high anodic stabilities. The possibility of operating graphite with 1 M LiDFOB & 1 M LiFSI ADN/DMC (1/1, wt./wt.) without additive is evidenced, with a clear advantage for the LiDFOB electrolyte. The addition of fluoroethylene carbonate (FEC) as a SEI additive results in improved graphite electrode performance in both cases and, less expectedly, in improved anodic stabilities. Cathodes operating above 4.3 V vs Li+/Li have been paired with graphite as well and allowed improved rate capability as compared to graphite half-cells. The safety of the electrolytes versus a charged graphite anode is improved as compared with state-of-the-art, EC-based electrolytes

Emerging calcium batteries

International audienceThis review depicts the present landscape in the field of calcium batteries, presenting a critical analysis of the state-of-the-art and estimating performance indicators to foresee the development of this technology. The practical realization of rechargeable Ca batteries still relies on the identification of suitable electrode and electrolytes. Despite reversible calcium plating-stripping being recently demonstrated, efforts are still needed to improve kinetics and efficiency and to allow a wider range of electrolyte formulations. In the very last years the spectrum of searched electrolytes and cathodes expanded to achieve proof-of-concept full Ca-batteries. Widening the electrochemical stability window of the electrolyte is crucial to push the development of positive electrodes operating at high potential. So far, only few interesting examples of inorganic cathode materials have been demonstrated. Sulfur and organic positive electrodes remain interesting pathways to follow. This work reviews electrode (positive and negative, including alloying and conversion compounds) and electrolyte materials, developed or modelled, and goes beyond, by addressing technical issues for potential Ca-cells upscaling. Based on a techno-economic analysis of different cell configurations, the performance figures-of-merit of this technology are discussed and related for the first time to EU targets and priorities established for the successful deployment of post-lithium batteries

Aerosol Spray Pyrolysis Synthesis of Doped LiNi_0.5Mn_1.5O₄ Cathode Materials for Next Generation Lithium-Ion Batteries

The autonomy of next generation Electric Vehicles relies on the development of high energy density automotive batteries. LiMn1.5Ni0.5O4 (spinel structure) is a promising active cathode material in terms of charge rate capability, theoretical capacity, cost and sustainability being a cobalt-free material. In the current study pristine and doped (Fe, Al, Mg) LiMn1.5Ni0.5O4 particles were synthesized by an Aerosol Spray Pyrolysis pilot scale unit in a production rate of 100 gr. h−1 and were evaluated for their electrochemical activity in Half Coin Cell form. The doped particles were characterized in terms of their surface area, particle size distribution, crystallite size, morphology and ion insertion of the doping element into the LiNi0.5Mn1.5O4 lattice by Raman spectroscopy. The mixed oxide particles had homogeneous composition which is an inert characteristic of aerosol spray pyrolysis synthesis. The electrochemical activity of the material is attributed both to the nanoscale structure, by successful dopant ion insertion into the spinel lattice as well as to optimization of carbon and spinel particle interface contact in the microscale for increase of electrode conductivity