Laminated Lithium Ion Batteries with improved fast charging capability

Fast charging technology for electric vehicles (EVs), which promises rapid charging times similar to refueling conventional vehicles, holds promise but encounters hurdles due to kinetic issues within lithium-ion batteries (LIBs). These issues include both kinetic and thermodynamic challenges within batteries, resulting in restricted utilization of active materials, Li plating, excessive heat generation, and accelerated capacity degradation.1 Efforts to tackle issues associated with fast charging have predominantly concentrated on modifying the Li salts in the electrolyte or the structure and surface/interface of the anode materials.However, compared to the electrolyte or anode materials, the importance of the cathode in relation to fast charging has not been significantly highlighted. Because properties such as the energy density, thermal stability, and rate performance of LIBs are largely determined by the cathode material, 2 understanding the characteristics of the cathode under high-current-density conditions is essential to comprehensively understand fast charging.In this study, the mechanism responsible for the loss of fast charging capability of Ni-rich cathodes during prolonged cycling is examined via a comparative analysis of Ni-rich cathodes exhibiting different microstructures. The results demonstrate that microcracks and subsequent cathode degradation notably compromise the fast charging capability over extended cycling periods. Formation of thick rocksalt impurity phases throughout the particles due to electrolyte infiltration via microcracks leads to limited kinetics of Li+ ions, resulting in electrochemically inactive regions under high-current conditions, hence leading to the loss of fast charging capability. Therefore, preventing microcrack formation by microstructural modification is imperative to ensure stability in fast charging capability. These findings underscore the need to comprehensively understand the degradation of the cathode during extended cycling, particularly from the perspective of the kinetic loss of utilizable Li+ ions at high currents, rather than just the loss of capacity. Reference s : [1] Y. Liu, Y. Zhu, Y. Cui, Nat. Energy, 2019, 4, 540.[2] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources, 2013, 233, 121.

Understanding the trilemma of fast charging, energy density and cycle life of lithium-ion batteries

To meet the growing demand for energy storage, lithium-ion batteries (LIBs) with fast charging capabilities has emerged as a critical technology. The electrode materials affect the rate performance significantly. Organic electrodes with structural flexibility support fast lithium-ion transport and are considered promising candidates for fast-charging LIBs. However, it is a challenge to create organic electrodes that can cycle steadily and reach high energy density in a few minutes. To solve this issue, accelerating the transport of electrons and lithium ions in the electrode is the key. Here, it is demonstrated that a ferrocene-based polymer electrode (Fc-SO3Li) can be used as a fast-charging organic electrode for LIBs. Thanks to its molecular architecture, LIBs with Fc-SO3Li show exceptional cycling stability (99.99% capacity retention after 10 000 cycles) and reach an energy density of 183Wh kg-1 in 72 seconds. Moreover, the composite material through insitu polymerization with Fc-SO3Li and 50 wt % carbon nanotube (denoted as Fc-SO3Li-CNT50) achieved optimized electron and ion transport pathways. After 10000 cycles at a high current density of 50C, it delivered a high energy density of 304Wh kg-1. This study provides valuable insights into designing cathode materials for LIBs that combine high power and ultralong cycle life.

The lithium-ion battery (LIB) is a key technology for inexpensive, renewable, and safe energy storage system, but there are a few challenges that need to be addressed to make LIB more efficient. One critical challenge is increasing both energy density and fast charging capability. Increasing electrode thickness can increase the energy density of lithium-ion batteries. However, increasing electrode thickness increases transport limitations and the risk of lithium plating, which limit safe fast charging capability. This work analyzes prospective improvements to the conventional lithium-ion cell electrode structure that may facilitate high energy density and fast charging capabilities. A 2D lithium-ion battery model is applied to five different cell designs to understand the impact of thick electrode structure on performance at different charge and discharge rates for a single cell. These five different cell designs consist of one conventional cell and four cells with electrodes modified by varied electrolyte channel arrangements. The simulated electrodes were taken as Li(Ni1/3Mn1/3Co1/3)O2 (NMC) for the cathode and graphite for the anode. The simulated electrolyte was 1 M lithium hexafluorophosphate (LiPF6) in 1:1 ethylene carbonate (EC) and diethylene carbonate (DEC). All five cells were simulated under discharge at C/10, C/2 and 1C followed by charge at 1C, 3C, and 5C with no rest time prior to charge. Adding electrolyte channels on the anode side was found to facilitate lithium ion transport and reduce the risk of lithium plating. Modification of both electrodes did not present any benefit compared to the conventional cell. Analysis of cell behavior based on mass transport Fourier number and a dimensionless mass flux parameter was performed to compare different electrodes at different charge and discharge conditions. These dimensionless parameters provide a means for the general assessment of prospective electrode structure modifications.

Achieving high-energy and high-power density Lithium-ion batteries (LIBs) with fast charging capabilities is critical to advancing electric vehicle (EV) and portable electronic technologies. Long-range, fast charge EVs and more compact portable electronics require significant advances in battery performance, lifetime, and cost. Conventional LIBs are composed of flat anode and cathode electrode stacks that can be optimized for energy or power, but not both concurrently. This is due to ion transport limitations that persist with increases in electrode thickness. Several research efforts have focused on optimizing LIB performance through material innovations with lithium metal and silicon anodes or new cathode materials, to name a few. Structured Electrode (SE) designs1 have been investigated over the last couple of decades as an alternate solution to address these challenges. SEs engineer electrode materials into different three-dimensional (3D) architectures on a scale ranging from tens to hundreds of microns to facilitate rapid ion-transport in thicker electrodes. While a promising concept, reliable and scalable manufacturing methods for fabricating SEs over the large and complex areas needed for EV and portable electronic applications remains limited.This talk covers manufacturing approaches investigated by our research group to fabricate SEs rapidly and efficiently. Both computational design and experimental approaches are employed to facilitate the development of new hardware, software, and processing techniques for SEs. Specifically, we highlight Additive Manufacturing (AM) tools for portable electronic applications and the use of acoustophoresis for manufacturing EV SEs. First, we have developed new computational fabrication tools2 and material formulations to push the bounds of AM for SE fabrication. Through this work, we investigate the impact of electrode design and fabrication on the rate capability and charge performance of Li4Ti5O12 and LiFePO4 cells. Next, taking AM towards larger area fabrication, we have combined acoustophoresis with AM principles to facilitate large-area printing and patterning of SEs for LIBs.3 Acoustophoresis utilizes acoustic standing wavesto drive particles into predefined patterns, with micron-scale control at time scales < 1 second. Our initial results with LiNi0.6Mn0.2Co0.2O2 and graphite have defined process conditions that enable acoustophoretic fabrication of SEs with improved rate capability over conventional, flat LIB electrodes. Our work highlights the material and processing considerations that must be given when developing new manufacturing processes for SEs. References C.-H. Hung, P. Huynh, K. Teo, and C.L. Cobb, “Are Three-dimensional Batteries Beneficial? Analyzing Historical Data to Elucidate Performance Advantages,” ACS Energy Letters, 8 (1), pp. 296–305, 2023.F. Fossdal, V. Nguyen, R. Heldal, C.L. Cobb, and N. Peek, “Vespidae: A Programming Framework for Developing Digital Fabrication Workflows,” In Proc. of 2023 Designing Interactive Systems Conference, ACM, New York, NY, USA.K.E. Johnson, D.S. Melchert, E.N. Armstrong, Daniel S. Gianola, C.L. Cobb, M.R. Begley, “A Simple, Validated Approach for Design of Two-dimensional Periodic Particle Patterns via Acoustophoresis,” Materials & Design, Vol. 232, 112165, 2023. Acknowledgements This material is based upon work supported in part by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Advanced Materials and Manufacturing Technologies Office (AMMTO) Award Numbers DE-EE0009112 and DE-EE0010226. The views expressed herein do not necessarily represent the views of the U.S. Department of Energy or the United States Government.This work was funded in part by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award and Director's Fellowship under grant number D19AP00038. The views, opinions, and findings expressed in this work are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government, and no official endorsement should be inferred. This is approved for public release and distribution is unlimited.

Along with the rapid growth in robots, mobile electronics and electric vehicles (EVs) technology, lithium ion batteries (LIBs) are facing several technical challenges such as higher energy density and fast charging capability. Graphite, currently used anode materials for LIBs, has technical limitations to be used for robots, mobile electronics and EVs in terms of energy density and fast charging capability. To solve these problems, various anode materials have been suggested for alternative graphite anode material. In this work, titanium dioxide coated graphite was investigated as an anode material with fast charging capability for LIBs. The proposed core-shell structure, titanium dioxide coated graphite anode electrode exhibited an excellent rate capability of 96.4 % of the capacity retention at a rate of 10 C compare to that tested at a rate of 0.2 C without any degradation of reversible capacity and long-term cycle performance. The characterization, microstructure and electrochemical properties of the titanium dioxide coated graphite will be discussed in more detail.

In order to mitigate the drastic volumetric expansion (>300%) of silicon (Si) during the lithiation process, we demonstrate the synthesis of novel Si nanowire arrays (n-SNWAs) with a coral-like surface on Cu foam via a one-step CVD method, in which the Cu foam can simultaneously act as a catalyst and current collector. The unique coral-like surface endows n-SNWAs with a high structural integrity, which is beneficial for enhancing their electrochemical performance. In addition, the as-prepared n-SNWAs on Cu foam can be directly applied as the anode for lithium-ion batteries (LIBs), exhibiting a very high reversible discharge capacity (2745 mA h g(-1) at 200 mA g(-1)) and a fast charge and discharge capability (884 mA h g(-1) at 3200 mA g(-1)), which is much higher than the conventional SNWAs (c-SNWAs, only 127 mA h g(-1) at 3200 mA g(-1)). Meanwhile, they deliver an improved cycling stability (2178 mA h g(-1) at 400 mA g(-1) after 50 cycles). More significantly, the as-synthesized n-SNWAs on Cu foam also possess a superior specific areal capacity of 4.1 mA h cm(-2) at 0.6 mA cm(-2). Such excellent electrochemical performance is superior, or at least comparable, to the best report for Si anode materials. Combining the cost-effective and facile preparation method, the present n-SNWAs on Cu foam can serve as a promising anode for LIBs.

Fast-charging capability and calendar life are critical metrics in rechargeable batteries, especially in silicon-based batteries that are susceptible to sluggish Li+ desolvation kinetics and HF-induced corrosion. No existing electrolyte simultaneously tackles both these pivotal challenges. Here we report a microscopically heterogeneous covalent organic nanosheet (CON) colloid electrolyte for extremely fast-charging and long-calendar-life Si-based lithium-ion batteries. Theoretical calculations and operando Raman spectroscopy reveal the fundamental mechanism of the multiscale noncovalent interaction, which involves the mesoscopic CON attenuating the microscopic Li+-solvent coordination, thereby expediting the Li+ desolvation kinetics. This electrolyte design enables extremely fast-charging capabilities of the full cell, both at 8 C (83.1 % state of charge) and 10 C (81.3 % state of charge). Remarkably, the colloid electrolyte demonstrates record-breaking cycling performance at 10 C (capacity retention of 92.39 % after 400 cycles). Moreover, benefiting from the robust adsorption capability of mesoporous CON towards HF and water, a notable improvement is observed in the calendar life of the full cell. This study highlights the role of microscopically heterogeneous colloid electrolytes in enhancing the fast-charging capability and calendar life of Si-based Li-ion batteries. Our work offers fresh perspectives on electrolyte design with multiscale interactions, providing insightful guidance for the development of alkali-ion/metal batteries operating under harsh environments.

The development of fast-charging anode materials is crucial for overcoming the sluggish reaction kinetics of conventional graphite electrodes in lithium-ion batteries. This work presents a kilogram-scale producible hard carbon/graphene flake (HC-GF) composite anode engineered based on an "electron Velcro" conductive network design. In this architecture, highly conductive GFs are intimately integrated with the HC matrix, creating multidimensional electron/ion transport channels while effectively minimizing interfacial resistance. The resulting HC-GF anode exhibits exceptional electrochemical performance, delivering a reversible capacity of 506.4 mAh g-1 and maintaining 223.8 mAh g-1 at a 10 C rate (corresponding to 6-min fast charging). Remarkably, when blended with graphite at a 20% ratio in a 5 Ah LFP//graphite + 20% (HC-GF) pouch cell, this minimal doping level substantially enhances multiple performance metrics, particularly fast-charging capability and cycling stability. The pouch cell retains 3.39 Ah after 600 cycles at 3 C, corresponding to an impressive capacity retention of 94.6%. This study provides a valuable material strategy for advancing fast-charging lithium-ion battery technologies.

Suppressing dendritic metallic Li formation on graphite anode under battery fast charging

The development of lithium-ion batteries with simplified assembling steps and fast charge capability is crucial for current battery applications. In this study, we propose a simple in-situ strategy for the construction of high-dispersive cobalt oxide (CoO) nanoneedle arrays, which grow vertically on a copper foam substrate. It is demonstrated that this nanoneedle CoO electrodes provide abundant electrochemical surface area. The resulting CoO arrays directly act as binder-free anodes in lithium-ion batteries with the copper foam functioning as the current collector. The highly-dispersed feature of the nanoneedle arrays enhances the effectiveness of active materials, leading to outstanding rate capability and superior long-term cycling stability. These impressive electrochemical properties are attributed to the highly-dispersed self-standing nanoarrays, the advantages of binder-free constituent, and the high exposed surface area of the copper foam substrate compared to copper foil, which enrich active surface area and facilitate charge transfer. The proposed approach to prepare binder-free lithium-ion battery anodes streamlines the electrode fabrication steps and holds significant promise for the future development of the battery industry.

In the recent years, fast-charging is a battery technology that continues to be in demand for portable devices, electric vehicles and grid storage. Especially, fast charging capability has become one of the key features targeted by battery and EV industries. However, charging at high rates has been shown to accelerate degradation, causing both the capacity and power capability of batteries to deteriorate. In addition, the efficiency of fast charging depends on the materials and current in the battery, but also ambient temperature is emerging as an important issue. When the ambient temperature decreases, there is a decrease in performance and battery stability problems. This is the reason that the diffusion of Li-ion is slower in the electrodes and the electrolyte at low temperatures due to sluggish kinetics of interaction. Therefore, it is recommended to use low charging speed and voltage at low ambient temperature. In order to increase the fast charging efficiency, the material and battery design must be well designed, and among them, by improving the ionic conductivity of the binder, the resistance of the entire battery is lowered and the fast charging efficiency is improved. In addition, the resistance of material change at low temperature and its effect on fast-charging were also examined.

For various applications of lithium-ion batteries, properties such as good cycling, fast charging capability, low self-discharge and especially over a wide temperature range are gaining importance. However, lithium-ion batteries suffer from intense energy and power losses in subzero temperatures, severely limiting their use in cold environments [1]. Earlier studies have shown that only 5% and 1.25% of the energy density and power density, respectively, of LIB at -40 ° C can deliver from their values at room temperature [2]. Poor low-temperature characteristics are primarily due to the slow kinetics of the electrochemical reaction at the interface, in addition to the low ionic conductivity and high viscosity of the electrolyte at such low temperatures.To solve this problem, efforts have been made to modify the composition of the electrolyte. However, traditional intercalation electrodes still suffer setbacks, especially during the charging process due to the slow desolvation process at low temperatures [3]. Therefore, in this work, a combined additive composed of ethylene carbonate (EC) with the properties such as high dielectric constant and excellent film-forming properties, and methyl acrylate (MA) with the properties such as low freezing point and high dielectric constant, was used. Acknowledgments: This work was supported by the project OPFE20211001 “New materials and devices for defense and aerospace applications” from the Ministry of Digital Development, Innovations and Aerospace Industry of the Republic of Kazakhstan

Fast charging of commercial lithium-ion batteries severely compromises long-term cycle durability, particularly in cells using high mass-loading thick electrodes. Such performance decay originates from interfacial kinetic limitations in the graphite anode as follows: (i) a sluggish Li+ desolvation at the electrolyte-graphite interface, (ii) a hindered Li+ diffusion across the solid electrolyte interphase (SEI), and (iii) a restricted Li+ insertion into the graphite, which collectively lead to an undesirable Li plating. Herein, we introduce an ultrathin and uniform MoO2/Mo2C biphasic passivation layer, achieved through a sequential cationic polyelectrolyte-assisted molybdate adsorption approach. The outer MoO2 layer does not only suppress an excessive SEI formation but also stabilizes the electrolyte interface by promoting the formation of Li2O and LiF-rich SEI that are both ionically conductive and chemically robust. The inner Mo2C layer provides a low Li+ adsorption energy (-0.97 eV), a reduced surface diffusion barrier (43 meV), and a high electrical conductivity (∼104 S cm-1), consequently enabling capacitive behavior and fast intercalation kinetics at the edge plane. The biphasic layer-passivated graphite anode delivers a fast-charging capability, reaching the 80% state of charge in just 7.4 min at a current density of 6 C and retaining 78.3% of its initial capacity after 600 fast-charge cycles with a practically viable high areal capacity of 3.2 mAh cm-2. These results represent a notable advancement over previously reported surface-engineered graphite anodes, particularly under industrially demanding conditions including high mass-loading and fast-charging.

Accelerating ion transport via in-situ formation of built-in electric field for fast charging sodium-ion batteries