Extreme Fast Charging Research Articles

Extreme Fast Charging and Stable Cycling of Lithium Manganese Oxide Batteries by Suppression of Cathode Phase Changes

Extreme Fast Charging and Stable Cycling of Lithium Manganese Oxide Batteries by Suppression of Cathode Phase Changes

Principles and trends in extreme fast charging lithium-ion batteries

This perspective summarizes principles and trends in extreme fast charging lithium-ion batteries, a key enabler of the mass adoption of electric vehicles.

Ampere-Hour-Scale Soft-Package Potassium-Ion Hybrid Capacitors Enabling 6-Minute Fast-Charging

Extreme fast charging of Ampere-hour (Ah)-scale electrochemical energy storage devices has emerged as a crucial target for advancing their widespread adoption in various applications, ranging from portable electronics to electric vehicles. The ability to recharge energy storage systems rapidly enhances convenience, productivity, and efficiency, driving the demand for technologies capable of achieving charging times of less than 10 minutes. However, conventional lithium-ion (Li-ion) batteries, ubiquitous in many electronic devices and electric vehicles, face significant challenges in meeting this demand due to their inherent reaction mechanisms and safety concerns associated with high current densities. Our work focuses on addressing the pressing need for extreme fast charging by introducing 1 Ah soft-package potassium-ion hybrid supercapacitors (PIHCs). These PIHCs are designed to leverage the combined merits of high-energy density from battery-type negative electrodes and high-power density from capacitor-type positive electrodes, offering a promising solution to the challenges posed by conventional Li-ion batteries. The architecture of the PIHCs is meticulously engineered to optimize performance while maintaining safety and reliability. The positive electrode of the PIHCs is composed of defect-rich, high specific surface area N-doped carbon nanotubes, facilitating efficient ion adsorption and desorption processes. On the other hand, the negative electrode incorporates MnO quantum dots inlaid within spacing-expanded carbon nanotubes, which provide ample active sites for potassium-ion storage and promote rapid charge transfer kinetics. Crucially, the electrolyte chosen for the PIHCs is a carbonate-based non-aqueous solution, carefully selected to ensure compatibility with the electrode materials and enable high ionic conductivity. Furthermore, the PIHCs feature a binder- and current collector-free cell design, reducing the overall weight and improving the energy density of the devices. Through systematic optimization of the cell configuration, electrode materials, and electrolyte composition, we have achieved remarkable performance metrics for the PIHCs. The full cells (1 Ah) exhibit a cell voltage of up to 4.8 V, enabling efficient energy storage and utilization. Importantly, the PIHCs demonstrate a high full-cell level specific energy of 140 Wh kg−1, calculated based on the entire mass of the device. Moreover, the extreme fast charging capability of the PIHCs is demonstrated through their remarkable charging time of only 6 minutes for a full 1 Ah capacity. This exceptional charging speed significantly enhances the usability and practicality of the PIHCs in various real-world applications, where rapid energy replenishment is essential. In addition to fast charging, the PIHCs exhibit excellent cycling stability and voltage retention under high current conditions. After 200 cycles at 10 C (corresponding to a discharge current of 10 A), the PIHCs maintain an impressive 88% capacity retention, highlighting their robustness and durability. Furthermore, the voltage retention of the PIHCs remains at 99% at a stable temperature of 25 ± 1 °C, underscoring their reliability and consistency over extended usage periods. Overall, the development of 1 Ah soft-package potassium-ion hybrid supercapacitors represents a significant advancement towards meeting the growing demand for extreme fast charging in electrochemical energy storage devices. By combining the advantages of battery-type and capacitor-type electrodes, along with innovative cell design and electrolyte selection, the PIHCs offer a compelling solution to the challenges posed by conventional Li-ion batteries, paving the way for the next generation of extreme fast charging energy storage technologies.[1]Ref. 1 H. Li etal. Nature Communications 14 (1), 6407 Figure 1

Lithium-Ion Battery Electrolyte Design for Extreme Fast-Charging

As the transition to electric vehicles accelerates, the need for fast charging of lithium-ion batteries (LIB) becomes increasingly important to address key consumer concerns such as range anxiety and limited charging infrastructure. Fast charging not only boosts the effective service capacity of charging infrastructure but also allows the use of higher-capacity batteries without long downtime. To advance the transition to EVs, the Department of Energy (DOE) has set high goals for extreme fast charging (XFC), where batteries should be charged to 80% capacity in under 10 mins[1].Operating under XFC conditions gives rise to high overpotentials in LIBs. The graphite electrode potential can be driven to below 0 V vs Li/Li+ due to the fast-charging overpotential, making Li plating thermodynamically favorable. Metallic lithium can grow as dendrites that pierce the separator and short the battery, creating safety concerns.[2] Some metallic lithium can also become electronically isolated, referred to as “dead lithium”, that cannot be recovered upon discharge.[3] Consequently, lithium plating remains a critical problem during fast charging that decreases total Li inventory and degrades the battery's overall capacity. In addition, charging under XFC conditions usually results in poor charge acceptance due to a combination of overpotential and extreme concentration gradients in the electrolyte.[4], [5], [6] Poor charge acceptance limits effective XFC protocol charging time and prolongs the overall time needed to charge LIBs.Our research investigates two concurrent strategies to enhance fast charging performance from fundamental considerations related to the electrolyte. In the first, a low-viscosity co-solvent such as acetonitrile is used to demonstrate the effect of improved electrolyte transport properties on fast charging. In the second, we show that the interfacial chemistry of graphite electrodes also plays a crucial role in fast charging. By developing a better understanding of the voltage-dependent formation mechanisms of the solid-electrolyte interface (SEI) with electrolyte additives such as FEC, we hope to leverage those insights into designing a better interface for XFC applications.[1] S. Ahmed et al., “Enabling fast charging – A battery technology gap assessment,” J. Power Sources, vol. 367, pp. 250–262, Nov. 2017, doi: 10.1016/j.jpowsour.2017.06.055.[2] X. Lin, K. Khosravinia, X. Hu, J. Li, and W. Lu, “Lithium Plating Mechanism, Detection, and Mitigation in Lithium-Ion Batteries,” Prog. Energy Combust. Sci., vol. 87, p. 100953, Nov. 2021, doi: 10.1016/j.pecs.2021.100953.[3] Z. M. Konz et al., “High-throughput Li plating quantification for fast-charging battery design,” Nat. Energy, pp. 1–12, Feb. 2023, doi: 10.1038/s41560-023-01194-y.[4] M. Weiss et al., “Fast Charging of Lithium-Ion Batteries: A Review of Materials Aspects,” Adv. Energy Mater., vol. 11, no. 33, p. 2101126, 2021, doi: 10.1002/aenm.202101126.[5] A. M. Colclasure, A. R. Dunlop, S. E. Trask, B. J. Polzin, A. N. Jansen, and K. Smith, “Requirements for Enabling Extreme Fast Charging of High Energy Density Li-Ion Cells while Avoiding Lithium Plating,” J. Electrochem. Soc., vol. 166, no. 8, p. A1412, Apr. 2019, doi: 10.1149/2.0451908jes.[6] A. M. Colclasure et al., “Electrode scale and electrolyte transport effects on extreme fast charging of lithium-ion cells,” Electrochimica Acta, vol. 337, p. 135854, Mar. 2020, doi: 10.1016/j.electacta.2020.135854.

Interplay of Thermal Gradients and C-Rate on Lithium Plating

Extreme fast charging (XFC) of lithium-ion batteries is crucial for solving range anxiety and rapid adoption of electric vehicles by significantly reducing charging time [1]. However, one of the key challenges in achieving this goal is lithium plating at the anode during the charging process [2]. Moreover, XFC will induce spatial temperature variations within the battery pack which will translate into thermal gradients inside a cell [3]. Interelectrode thermal gradients were previously found to induce accelerated lithium plating, degrading the battery life drastically [4], [5]. Therefore, it is critical to understand the complex interplay between C-rate and thermal gradients on lithium plating and its governing mechanisms. In this work, we investigate lithium plating under various thermal gradients and C-rates in single-layer NMC/graphite instrumented pouch cells. Thermistors were placed inside the cell at each electrode to precisely measure the magnitude of the thermal gradient conditions being applied. Galvanostatic cycling was performed at different C-rates and interelectrode thermal gradients. A comprehensive analysis was performed, including incremental capacity analysis. Three-electrode cells were utilized to isolate graphite-specific electrochemical processes and decipher the governing mechanisms. Post-mortem analysis was also performed to corroborate the electrochemical behavior. Acknowledgments The authors thank Dr. Michele Anderson (Office of Naval Research, grant N00014-22-1-2411) for financial support of this work. The authors also acknowledge Dr. Rachel Carter (U.S. Naval Research Laboratory) for technical discussion of this work.

Optimizing Lithium-Ion Batteries for Extended Extreme-Fast Charging: Strategies to Prevent Lithium Plating without Compromising Charge Acceptance

Enabling Extreme Fast Charging (XFC), particularly achieving a 10-minute charge cycle, represents a significant technological milestone. Accomplishing this objective necessitates a comprehensive comprehension of the intricate interactions inherent within Lithium-ion batteries (LiBs), encompassing their operational dynamics and aging characteristics. Realizing XFC entails the implementation of diverse solutions, such as sophisticated materials-to-electrode design methodologies and meticulously devised charging protocols. This presentation aims to delineate various solution strategies that have demonstrated efficacy in facilitating XFC in LiBs across numerous charge-discharge cycles in moderate-loading cells (3 mAh/cm2 anode versus 2.7 mAh/cm2 cathode). Furthermore, it will investigate aging phenomena at various scales, thereby contributing to a deeper comprehension of this technological advancement.The cell assemblies investigated in the forthcoming study employed multiple solution strategies, including: (1) Preference for NMC811 over NMC532 as the cathode material, (2) Adoption of an optimized carbon binder domain in NMC811, (3) Implementation of a dual-layer anode (DLA), (4) Transition to a higher-pore-volume separator, (5) Integration of an advanced electrolyte such as B26, and (6) Application of advanced charge protocols. These strategies collectively augment lithium-ion transport within the cell, consequently mitigating overall cell overpotential losses and diminishing cell degradation across diverse length scales. As a result, they effectively inhibit lithium plating even after undergoing hundreds of charging cycles.Cells implementing the six solution strategies attained an 87.3% charge acceptance within a 10-minute timeframe, employing a 6C CC-CV charge protocol with a cutoff voltage set at 4.1V. Following 600 cycles, these cells exhibited an 11.5% degradation rate, with no discernible evidence of lithium plating, equating to a driving range equivalent to 171,000 miles and a charging speed of up to 26 miles/min.XFC employing a higher charge cutoff voltage of 4.15V yielded a marginally improved charge acceptance ranging from 3.5% to 4.8% for two advanced charge protocols, namely Material Stress Reduction (MSR) and Voltage Ramp (VR), albeit with accelerated aging. Despite modifications to the MSR protocol, it did not entirely mitigate lithium plating; however, the VR profile achieved a noteworthy 92.1% charge acceptance within 10 minutes, experiencing a 13.9% capacity fade after 600 cycles at a 4.15V charge cutoff, thereby avoiding lithium plating. This translates to a fast-charge range spanning from 171,000 to 181,000 miles, satisfying current prevailing electric vehicle (EV) warranty and longevity objectives, with a charging rate ranging from 26 to 27 miles/min, in alignment with the Department of Energy's XFC goal of 20 miles/min.The findings of this study confirm the advantages of integrating various solution strategies to enable XFC. These encouraging outcomes pave the way for achieving a 10-minute XFC capability in energy-optimized cells with loading capacities of ≥4 mAh/cm2.

(Invited) Accelerating Battery R&D from Materials-to-Device Using AI and Data

Data-driven research promises to accelerate the development of novel electrochemical energy storage technologies. Atomistic- to materials-scale efforts include discovery and synthesis through autonomous “self-driving” laboratories [1,2]. Here, we present several continuum-scale efforts where a complete electrochemical couple is tested at length scales ranging from coin cell (laboratory) to complete system (field) and linked with physics-based AI algorithms to compress development time. We highlight successes and challenges transferring learning across chemistries, designs [3], and operating conditions [4], as well as parameter inference, uncertainty quantification [5,6], multi-modal and explainable AI/ML.The Battery Data Genome (BDG) [7] laid out a vision for a collection of disparate open-source and proprietary data hubs to unify around a standardized/tagged data format and interchangeable algorithms, linking multiple research groups and industry to bridge “valleys of death” in technology development. BDG also described challenge problems around performance, state of health, lifetime, safety, and acceleration of materials & manufacturing development. This talk further highlights two programs supported by U.S. Department of Energy (DOE) which seek to accelerate battery technology transition from lab to full-scale commercialization.The first program, funded by DOE’s Vehicle Technologies Office, is new data hub (batterydata.energy.gov) hosting pre-competitive battery R&D data focused on materials/electrode performance and battery design. To promote transfer learning, metadata define electrode & electrolyte recipes/chemistry, cell design, and test condition. Data can be either public [3,8] or private, the latter protected by two-factor authentication. Visualization and analysis algorithms enable researchers to share insights faster than previously possible. Compared to datahubs storing commercial data, batterydata.energy.gov is unique in that it stores pre-commercial R&D data. It thus serves as a repository for challenge problems related to battery materials research, design, and manufacturing.The second program, Rapid Operational Validation Initiative (ROVI), is funded by DOE’s Office of Electricity. The ROVI objective is to predict 15-year investment-grade performance with just one year of R&D data plus limited field data for long-duration energy storage technologies. The program is linking empirical and physics-based models with AI diagnostics/prognostics algorithms for monitoring/forecasting health/life from cell-level lab testing to system-scale real-world operation [9]. Amici et al., “A Roadmap for Transforming Research to Invent the Batteries of the Future Designed within the European Large Scale Research Initiative BATTERY 2030+,” Adv. Energy Mat., 2022, 12, 2102785.Dave, J. Mitchell, S. Burke, H. Lin, J. Whitacre, V. Viswanathan, “Autonomous optimization of nonaqueous Li-ion battery electrolytes via robotic experimentation and machine learning coupling,” Nature Communications 13, 5454 (2022).J. Weddle, S. Kim, B.R. Chen, Z. Yi, P. Gasper, A.M. Colclasure, K. Smith, K.L. Gering, T.R. Tanim, E.J. Dufek, “Battery state-of-health diagnostics during fast cycling using physics-informed deep-learning,” J. Power Sources, 585 (2023) 233582.Gasper, N. Collath, H.C. Hesse, A. Jossen, K. Smith, “Machine-learning assisted identification of accurate battery lifetime models with uncertainty,” J. Electrochem. Society 169 (2022) 080518.Hassanaly, P.J. Weddle, R.N. King, S. De, A. Doostan, C.R. Randall, E. Dufek, K. Smith, “PINN surrogate of Li-ion battery models for parametric inference. Part I: Implementation and multi-fidelity hierarchies for the single-particle model,” submitted.Hassanaly, P.J. Weddle, R.N. King, S. De, A. Doostan, C.R. Randall, E. Dufek, K. Smith, “PINN surrogate of Li-ion battery models for parametric inference. Part II: Regularization and application of the pseudo-2D model,” submitted.Ward, S. Babinec, E.J. Dufek, D.A. Howey, V. Viswanathan, M. Aykol, D.A.C. Beck, B. Blaiszik, B.-R. Chen, G. Crabtree, S. Clark, V. de Angelis, P. Dechent, M. Dubarry, E.E. Eggleton, D.P. Finegan, I. Foster, C. Gopal, P. Herring, V.W. Hu, N.H. Paulson, Y. Preger, D.U. Sauer, K. Smith, S. Snyder, S. Sripad, T.R. Tanim, L. Tao, “Principles of the Battery Data Genome,” Joule 6 (2022) 2253.Smith, A. Saxon, M. Keyser, B. Lundstrom, Z. Cao, A. Roc, “Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System,” American Control Conference, Seattle, WA, May 30-June 1, 2017.D. Guittet, P. Gasper, M. Shirk, M. Mitchell, M. Gilleran, E. Bonnema, K. Smith, P. Mishra, M. Mann, “Levelized cost of charging of extreme fast charging with stationary LMO/LTO batteries,” J. Energy Storage, 82 (2024) 110568.

Tailoring-Orientated Deposition of Li2S for Extreme Fast-Charging Lithium-Sulfur Batteries.

Precipitation/dissolution of insulating Li2S has long been recognized as the rate-determining step in lithium-sulfur (Li-S) batteries, which dramatically undermines sulfur utilization at elevated charging rates. Herein, we present an orientated Li2S deposition strategy to achieve extreme fast charging (XFC, ≤15 min) through synergistic control of porosity, electronic conductivity, and anchoring sites of electrode substrate. Via magnesiothermic reduction of a zeolitic imidazolate framework, a nitrogen-doped and hierarchical porous carbon with highly graphitic phase was developed. This design effectively reduces interfacial resistance and ensures efficient sequestration of polysulfides during deposition, leading to (110)-preferred growth of Li2S nanocrystalline between (002)-dominated graphitic layers. Our approach directs an alternative Li2S deposition pathway to the commonly reported lateral growth and 3D thickening growth mode, ameliorating the electrode passivation. Therefore, a Li-S cell capable of charging/discharging at 5C (12 min) while maintaining excellent cycling stability (82% capacity retention) for 1000 cycles is demonstrated. Even under high S loading (8.3 mg cm-2) and low electrolyte/sulfur ratio (3.8 mL mg-1), the sulfur cathode still delivers a high areal capacity of >7 mAh cm-2 for 80 cycles.

Covalent Carbide Interconnects Enable Robust Interfaces and Thin SEI for Graphite Anode Stability under Extreme Fast Charging.

Carbonaceous and carbon-coated electrodes are ubiquitous in electrochemical energy storage and conversion technologies due to their electrochemical stability, lightweight nature, and relatively low cost. However, traditional reliance on conductive additives and binders leads to impermanent electrical pathways. Here, a general approach is presented to fabricate robust electrodes with a progressive failure mechanism by introducing carbide-based interconnects grown via carbothermal conversion of (5 wt%) titanium hydride nanoparticles. This method concurrently enhances both electrical and mechanical properties within the electrode architecture. The resulting chemical bonding between active materials establishes a novel mechanism to maintain stable electrical pathways during cycling. Employed as Li-ion battery anodes, these electrodes exhibit improved cyclability, achieving 80% capacity retention after 800 fast-charge cycles at moderate loading (1 mAh cm- 2). High loading cells with areal capacity of 3 mAh cm-2 show significantly improved cycle lifeover the same number of cycles. This performance improvement is attributed to the absence of significant impedance growth and a thinner solid electrolyte interphase (SEI) layer formed at high current densities (4C) as demonstrated by X-ray photoelectron spectroscopy and transmission electron microscopy studies. The enhanced conductivity facilitates SEI formation, lowering ionic impedance and mitigating lithium plating, ultimately leading to the reported extended cycle life.

Multistage Linkage Internal Exclusion External Electrolyte Tactic Unlocks Extreme Fast Charge Lithium Metal Batteries.

Lithium metal batteries are booming because of their inherent preponderance, but a negative electric field from concentration dipolarization and slow solid-phase transfer at the electrode interface become blocking modules for extreme fast charging. Achieving an anion-rich solvation shell with a high dielectric constant (ε) is a feasible strategy to bootstrap an interface microenvironment for mass-transport reaction, but it is still an uncultivated field. Herein, the superposition, including the donor number values, the high ε, and the spatial potential resistance, are complementarily considered; we propose a low-cost electrolyte with an internal excluding external tactic to answer the above issue. Explanatorily, an optimized solvation shell follows the cascading exclusion relationship of nitrate ion (NO3-) → tetraglyme → ethylene carbonate → dimethyl carbonate. And the culminated bilayer structure establishes ideal conditions for Li+ transfer-reaction kinetics, of which an anion-rich internal shell facilitates solid-phase transport and a high-ε external shell slashes the negative electric field.

(Energy Technology Division Graduate Student Award sponsored by BioLogic) In-Situ, Non-Destructive, 3D Neutron Imaging of Lithium Plating Following Extreme Fast-Charging of Full-Cell Lithium-Ion Batteries

One of the primary challenges impeding extreme fast-charging (XFC) of current lithium-ion batteries (LIBs) for electric vehicles (EVs) within 10–15 minutes is the deposition of Li metal on graphite known as “Li plating”.1-2 After Li plates, it either re-intercalates into the graphite electrode or is stripped off during battery discharging to form “active Li”or becomes electronically disconnected resulting in “dead Li.” Previous studies have indicated that dead Li is the main contributor to the XFC-related capacity loss of LIBs. However, mechanistic understanding of the 3D morphological behavior and spatial heterogeneities of dead Li; and how they differ from those of plated and active Li during the XFC is not well understood.3-4 Here, we present an in-situ, non-destructive 3D characterization of the morphological behavior and spatial heterogeneities of plated, dead, and active Li on graphite electrodes in full-cell LIBs using high-resolution neutron micro-computed tomography. We performed neutron µCT5 (pixel size: ~ 5.74 µm; effective spatial resolution: ~10-15 µm) at the ICON beamline6 at the Swiss Spallation Neutron Source at the Paul Scherrer Institute. We imaged two batteries in the charged and discharged states: (1) after 4 cycles of 1C charging and (2) after 6 cycles of 6C charging.Our results show that Li plates at and around the edges of the graphite electrodes, indicating that graphite edges and the areas around these edges are the most susceptible to Li plating. However, certain edges and areas around these edges formed dead Li whereas others formed active Li, suggesting 3D spatial heterogeneities in the formation of dead and active Li at both 1C and 6C. Mainly, we discuss these heterogeneities at four regions: (1) near the Cu CC, (2) in the middle of the graphite electrode, (3) near the graphite-separator interface, and (4) in the separator. Specifically, we found that Li near the Cu CC remains active whereas most of the plated Li at the graphite-separator interface and in the separator becomes dead at both 1C and 6C.Morphologically, we observed porous nature of plated and dead Li at both 1C and 6C. Our 3D visualizations noticeably show nodules of varying densities of metallic Li. However, we observed different 3D behavior of Li plating at 1C and 6C. For example, tip-like Li deposits were seen laterally closer to the center of the graphite electrode, near the graphite-separator interface, and into the separator at 6C. In contrast, at 1C, no tip-like Li deposits were observed near the graphite-separator interface and into the separator. Based on our findings, we concluded that higher XFC-charging rate and cycling number (6 cycles of 6C charging) cause the formation of tip-like Li deposits as compared to the relatively slower XFC-charging rate and cycling number (4 cycles of 1C charging). We believe that insights derived from this work will guide the design of thick graphite electrodes with minimized-plating for fast-charged EVs.

Prelithiated Silicon Anodes for High-Energy and High-Power Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are pivotal in powering modern electronic devices and next-generation land and air electric vehicles. Silicon-based anodes are considered the next technology to replace traditional graphite anodes due to their high theoretical capacity. However, the inherent challenges associated with their large volume expansion and high irreversible capacity loss (IRCL) limit their practical application. This abstract explores our patented strategy of prelithiation as a viable approach to mitigate the IRCL limitations of SiOx dominant anodes. Prelithiation involves the precise addition of supplemental lithium into the anode, mitigating the adverse effects of initial lithiation and enhancing overall cyclability, energy, power, and extreme fast charge capability for silicon oxide dominant LIBs. Various prelithiation techniques, including Li powder, Li slurry, Li-foil, and the chemical doping of SiOx are examined to evaluate their effectiveness in providing supplemental lithium. The effectiveness of the prelithiation process is assessed by examining the impact on the structural stability, cycling performance, power capability, and rate capability of SiOx dominant anodes integrated into high-capacity (~30 Ah) pouch cells. Our focus is to emphasize prelithiation as a practical and scalable solution to enhance the electrochemical performance of SiOx dominant anodes, contributing to the development of high-energy and high-power LIBs enabling advanced air mobility and high-performance electric vehicles. The findings presented in this abstract contribute to the growing body of knowledge aimed at advancing the fundamental understanding and practical implementation of prelithiation as an enabler for SiOx-based anodes in LIBs. Figure 1

Ionblox’s SiOx-Based, High-Energy, High-Power Li-Ion Battery for Performance Electric Vehicles and Electric Aviation

Demands on land-based, high-performance electric vehicles (EVs) and electric aviation, by means of electric conventional takeoff and landing aircraft (eCTOLs) and electric vertical takeoff and landing aircraft (eVTOLs) demand more on a secondary cell chemistry than ever before. There are many secondary cells on the market that offer energy density, power density, fast-charge capability, or cycle life, but few, if any other manufacturing-ready cells, offer a combination of all four. IONBLOX has solved this by pairing it’s patented, Pre-lithiated SiOx anode with a high nickel, NMC cathode to produce cells exceeding 330 wh/kg. Herein we describe the performance of our 32 Ah cell, featuring high-energy density, high-power density, extreme fast charge capability, and good cycle life, within a package that is already in production.In particular, challenges for the eVTOL market will be addressed, which require peak power demand on the cell at low state-of-charge, without reducing the energy density. Methods for characterizing cells for such high-power applications will be further explored. DCIR pulse characterization and more customized testing like usable energy testing, which is important for identifying the applicable energy density for high-power use cases, will be demonstrated. Additionally, extreme fast charge capability is described on our large format cells with 5 min charge to >60% total cell capacity, over 1000 cycles. This shows such a cell is up to the expectations of a consumer familiar with the timing of a standard gasoline pump. Contribution from the information presented herein demonstrates the state of Si-based anode chemistry and can serve as useful guidelines to the academic community as future technologies are pursued for similar applications Figure 1

Investigation of 40 Ah Prismatic Batteries Operating Under Fast-Charge Conditions Using Operando Synchrotron XRD Technique

The pressing challenges posed by the energy crisis and the impact of climate change have forced a gradual replacement of traditional internal combustion engine (ICE) automobile powertrains with electrochemical energy storage devices. However, a boost of the electric vehicles (EVs) market, by significant battery performance enhancements are consistently required, primarily due to numerous persistent concerns. One of the key features targeted by battery and EVs industries is the rapid charging capability, making EVs more competitive with the quick refueling of traditional gasoline vehicles. Notably, despite the clear benefits of fast charging technology, the accelerated battery degradation after fast and extreme fast charging raises on top of the drawbacks of this technology. Therefore, understanding of heterogeneity and structural transformations within battery systems is of high interest.In this regard, we attempt to investigate the structural properties of a LiNi1/3Mn1/3Co1/3O2 (NMC111) /graphite fresh industrial prismatic cell using synchrotron XRD under fast charge conditions. The investigated battery is a PHEV cell with an experimental capacity of 40 Ah. It was taken from a range rover vehicle pack after being disassembled. The evolution of the composite anode and cathode structures was followed by operando wide-angle X-ray scattering (WAXS). Using this approach, we were able to measure and quantify the different phases of graphite and NMC111 lithiation/delithiation at various potentials by analyzing the corresponding Bragg peaks. By that, we were able to detect some heterogeneities in the degree of lithiation/delithiation within the cell upon charge. In addition, a comparison between a fresh cell and another aged cell, with a state of health (SOH) of 88%, was made in order to investigate the effect of aging under fast charging conditions on the performance of the industrial LIBs.

Ferrocene-Based Polymer Organic Cathode for Extreme Fast Charging Lithium-Ion Batteries with Ultralong Lifespans.

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.

Extreme Fast Charging of Lithium Metal Batteries Enabled by a Molten-Salt-Derived Nanocrystal Interphase.

The extreme fast charging performance of lithium metal batteries (LMBs) with a long life is an important focus in the development of next-generation battery technologies. The friable solid electrolyte interphase and dendritic lithium growth are major problems. The formation of an inorganic nanocrystal-dominant interphase produced by preimmersing the Li in molten lithium bis(fluorosulfonyl)imide that suppresses the overgrowth of the usual interphase is reported. Its high surface modulus combined with fast Li+ diffusivity enables a reversible dendrite-proof deposition under ultrahigh-rate conditions. It gives a record-breaking cumulative plating/stripping capacity of >240000 mAh cm-2 at 30mA cm-2@30 mAh cm-2 for a symmetric cell and an extreme fast charging performance at 6 C for 500 cycles for a Li||LiCoO2 full cell with a high-areal-capacity, thus expanding the use of LMBs to high-loading and power-intensive scenarios. Its usability both in roll-to-roll production and in different electrolytes indicating the scalable and industrial potential of this process for high-performance LMBs.

Temperature-dependence vanadium regulation for extreme fast charging LiFePO4 cathode materials with multilevel core-shell structure

Lithium-ion batteries (LIBs) with LiFePO4 cathode are widely used in electric vehicles and energy storage systems owing to their cost-effectiveness and safety. However, this type of LIBs is limited by poor fast-charging capabilities owing to the inherent poor electronic conductivity and one-dimensional ionic pathways. Herein, we show that the approach of temperature-dependence vanadium (V) regulation can greatly improve the Li+ diffusion dynamics both in bulk and at interface, leading to the achievement of ultrafast charging/discharging capability of LiFePO4-based LIBs. The formation of V3+ doping induced Fe-site vacancy in bulk and Li3V2(PO4)3 phase at interface with high ionic conductivity can be achieved at the optimal conditions of 700°C and 0.10 V content. Additionally, this regulatory V effect endows the LiFe1-3/2xVxPO4 (LFVP) materials with a specific multilevel core-shell structure. Consequently, the optimal LFVP-0.10-700 sample delivers high specific capacities of 169.6 mAh g−1 at 0.1 C with an excellent capacity retention of 97.5 % after 200 cycles at 1 C, as well as ∼100 mAh g−1 at an ultrahigh rate of 50 C for 3500 cycles. These performances make LiFePO4 cathode possible for extreme fast charging LIBs.

Fast-Charging Phosphorus-Based Anodes: Promises, Challenges, and Pathways for Improvement.

Fast-charging batteries are highly sought after. However, the current battery industry has used carbon as the preferred anode, which can suffer from dendrite formation problems at high current density, causing failure after prolonged cycling and posing safety hazards. The phosphorus (P) anode is being considered as a promising successor to graphite due to its safe lithiation potential, low ion diffusion energy barrier, and high theoretical storage capacity. Since 2019, fast-charging P-based anodes have realized the goals of extreme fast charging (XFC), which enables a 10 min recharging time to deliver a capacity retention larger than 80%. Rechargeable battery technologies that use P-based anodes, along with high-capacity conversion-type cathodes or high-voltage insertion-type cathodes, have thus garnered substantial attention from both the academic and industry communities. In spite of this activity, there remains a rather sparse range of high-performance and fast-charging P-based cell configurations. Herein, we first systematically examine four challenges for fast-charging P-based anodes, including the volumetric variation during the cycling process, the electrode interfacial instability, the dissolution of polyphosphides, and the long-lasting P/electrolyte side reactions. Next, we summarize a range of strategies with the potential to circumvent these challenges and rationally control electrochemical reaction processes at the P anode. We also consider both binders and electrode structures. We also propose other remaining issues and corresponding strategies for the improvement and understanding of the fast-charging P anode. Finally, we review and discuss the existing full cell configurations based on P anodes and forecast the potential feasibility of recycling spent P-based full cells according to the trajectory of recent developments in batteries. We hope this review affords a fresh perspective on P science and engineering toward fast-charging energy storage devices.

Dominant Solvent-Separated Ion Pairs in Electrolytes Enable Superhigh Conductivity for Fast-Charging and Low-Temperature Lithium Ion Batteries.

The low ionic conductivities of aprotic electrolytes hinder the development of extreme fast charging technologies and applications at low temperatures for lithium-ion batteries (LIBs). Herein, we present an electrolyte with LiFSI in acetone (DMK). In DMK electrolytes, the solvation number is three, and solvent-separated ion pairs (SSIPs) are the dominant structure, which is largely different from other linear aprotic electrolytes where salts primarily exist as contact ion pairs (CIPs). With incompact solvation structures due to the weak solvation ability of DMK with Li+, the ionic conductivity reaches 45 mS/cm at room temperature. The percentage of SSIPs increases as temperatures decrease in DMK electrolytes, which is totally different from the carbonate-based electrolytes but greatly beneficial to low-temperature ionic conductivity. With the appropriate addition of VC and FEC, DMK-based electrolytes still exhibit a superhigh ionic conductivity. Even at -40 °C, the ionic conductivity is greater than 10 mS/cm. With DMK-based electrolytes, LIBs with thick LiFePO4 electrodes can be cycled at high rates and at low temperatures.

Multilayered Energy Management Framework for Extreme Fast Charging Stations Considering Demand Charges, Battery Degradation, and Forecast Uncertainties

To achieve a cost-effective and expeditious charging experience for extreme fast charging station (XFCS) owners and electric vehicle (EV) users, the optimal operation of XFCS is crucial. It is however challenging to simultaneously manage the profit from energy arbitrage, the cost of demand charges, and the degradation of a battery energy storage system (BESS) under uncertainties. This paper, therefore, proposes a multi-layered multi-time scale energy flow management framework for an XFCS by considering long- and short-term forecast uncertainties, monthly demand charges reduction, and BESS life degradation. In the proposed approach, an upper scheduling layer (USL) ensures the overall operation economy and yields optimal scheduling of the energy resources on a rolling horizon basis, thereby considering the long-term forecast errors. A lower dispatch layer (LDL) takes the short-term forecast errors into account during the real-time operation of the XFCS. Per the latest research, monthly demand charges can be as high as 90% of the total monthly bills for EV fast charging stations; to this end, this paper takes the first attempt at the reduction of demand charges cost by considering the trade-off between the energy cost and monthly demand charges. Contrasting literature, this work allocates an energy reserve in the BESS stored energy to deal with the impact of short-term forecast errors on the optimized real-time operation of the XFCS. Moreover, degradation modeling considers the trade-off between short-term benefits and long-term BESS life degradation. Lastly, case studies and a comparative analysis prove the efficacy of the proposed framework.