Widespread Adoption Of Electric Vehicles Research Articles

In‐Depth Analysis of the Degradation Mechanisms of High‐Nickel, Low/No‐Cobalt Layered Oxide Cathodes for Lithium‐Ion Batteries

AbstractA rational compositional design of high‐nickel, cobalt‐free layered oxide materials for high‐energy and low‐cost lithium‐ion batteries would be expected to further propel the widespread adoption of electric vehicles (EVs), yet a composition with satisfactory electrochemical properties has yet to emerge. The previous work has demonstrated a promising LiNi0.883Mn0.056Al0.061O2 (NMA‐89) composition that outperformed high‐nickel, cobalt‐containing analogs in cycling stability and maintained a comparable rate performance and thermal stability. Herein, the capacity fading mechanism of NMA‐89 in a pouch full cell with a 4.2 V cutoff is compared to that of its cobalt‐containing analogs. The results reveal that particle cracking in LiNi0.89Mn0.055Co0.055O2 (NMC‐89) and LiNi0.883Co0.053Al0.064O2 (NCA‐89) leads to a loss of active material and an increase in surface area, thereby exacerbating structural and surface instabilities, accelerating impedance and polarization growth, and ultimately reducing their capacity retentions. LiNi0.89Mn0.044Co0.042Al0.013Mg0.011O2 (NMCAM‐89) and NMA‐89 experience subdued surface reactions and maintain spherical particle structures, both of which are conducive to their capacity retentions during long‐term cycling. This investigation offers insights into how specific transition‐metal ions dictate the electrochemical stability of high‐Ni layered oxide cathode materials, highlights the benefit of Mn‐Al combination in NMA‐89, and presents potential strategies to further enhance the performance of this novel class of cathode materials.

3D Detection of Lithiation and Lithium Plating in Graphite Anodes during Fast Charging.

A barrier to the widespread adoption of electric vehicles is enabling fast charging lithium-ion batteries. At normal charging rates, lithium ions intercalate into the graphite electrode. At high charging rates, lithiation is inhomogeneous, and metallic lithium can plate on the graphite particles, reducing capacity and causing safety concerns. We have built a cell for conducting high-resolution in situ X-ray microtomography experiments to quantify three-dimensional lithiation inhomogeneity and lithium plating. Our studies reveal an unexpected correlation between these two phenomena. During fast charging, a layer of mossy lithium metal plates at the graphite electrode-separator interface. The transport bottlenecks resulting from this layer lead to underlithiated graphite particles well-removed from the separator, near the current collector. These underlithiated particles lie directly underneath the mossy lithium, suggesting that lithium plating inhibits further lithiation of the underlying electrode.

(Industrial Electrochemistry and Electrochemical Engineering Division Student Achievement Award) Mass Spectrometry Titration for Quantitative Probing of Lithium Plating and Solid-Electrolyte Interphase Formation

Rapid charging of lithium-ion batteries is crucial to encourage widespread adoption of electric vehicles, yet the precipitous capacity fade which typically accompanies fast charge limits its utility. Li plating on the graphite anode, which occurs due to the high overpotentials enacted during fast charge, is known to instigate this capacity fade, making precisely identifying the onset and amount of Li plating imperative. Methods have been proposed to detect plating, but these methods typically detect Li indirectly and non-quantitatively. In this presentation, I will outline a novel mass spectrometry titration (MST) technique, which I use to quantify inactive Li (defined as electrically isolated Li metal and LixC6 that remains on the electrode after cycling) via the amount of H2 evolved upon exposure to a sulfuric acid titrant. I extend the technique to additionally quantify carbonate-containing species (via CO2 evolution upon titration) and lithium acetylide (Li2C2, via the C2H2 evolution upon titration) in the solid-electrolyte interphase (SEI), and I demonstrate the utility of MST in characterizing the SEI formed under novel electrolyte formulations. Finally, I will show how MST can be strategically used to determine the onset of Li plating and to distinguish between the multiple capacity fade mechanisms that arise during fast charge.

A Critical Investigation of the Viability of Fast Charging of Lithium-Metal Batteries in Glyme-Ether Electrolytes

Widespread adoption of electric vehicles (EVs) largely depends on the development of efficient battery systems having high energy density with the capability of fast charging. In this regard, lithium (Li) metal-based batteries, such as Li-Oxygen and Li-Sulfur batteries, can provide much higher energy density compared to that of Li-ion batteries. However, low rate-capability of both Li-Oxygen and Li-Sulfur cells hinders their practical utilizations. It has been found that transport limitations in the electrolyte play a major role in affecting the rate-capability of the cells. Therefore, identifying a suitable electrolyte with high ionic conductivity is an essential requirement to improve the rate-capability of these batteries. Additionally, a desired electrolyte must also be stable toward the electrode processes in the cell. Glyme-ether based electrolytes, in these instances, are a preferred class of electrolytes for both Li-Oxygen and Li-Sulfur batteries due to their acceptable compatibility with Li metal as well as with the porous carbon electrodes. Nevertheless, the length of the glyme-ethers dramatically affects the ionic conductivities of the electrolytes and decides the rate-capability of the battery. Therefore, in this work we have investigated the viability of fast Li-plating in different glyme-ether electrolytes and critically analyzed the effects of ion-transport and also assessed the relative stabilities of the electrolytes during Li stripping/plating processes.The present study involves investigation of Li stripping/plating in six different electrolytes using three glyme-ethers, diglyme (G2), triglyme (G3) and tetraglyme (G4), as the electrolyte solvents with lithium nitrate (LiNO3) or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as the Li salts (1 M) and lithium bromide (LiBr) as an additive (0.05 M). It has been found that the ionic conductivity of the electrolyte increases as the glyme becomes smaller or highly associated LiNO3 is replaced with LiTFSI. As a result, both smaller glymes and LiTFSI help to achieve Li-plating at faster rates. However, unfortunately, stability of Li-plating in terms of Coulombic efficiency and overall cycle-life decreases in smaller glymes or in LiTFSI as the Li salt and detailed investigations reveal formation of unstable SEI to be responsible for lower stability of Li-plating in these electrolytes. Our results show that the consequences of increasing the ionic conductivity of the electrolyte by simply changing the glyme-ether solvent in Li-metal batteries are quite complex and warrant careful consideration of their relative stabilities with the electrode. All the results, in depth analyses and future perspectives of this work will be discussed during the presentation.

Electron Microscopy Investigation of Graphite Electrodes from Fast-Charged Lithium-Ion Cells

Lithium-ion batteries (LIBs) capable of safe and reliable cycling at a fast-charge rate (i.e., >2C or <30 minutes to full charge) will have a direct impact on today’s consumer technology by improving the utility of portable electronics and reducing the barrier for widespread adoption of electric vehicles. However, at high charge rates, the long-term battery performance suffers because of heterogeneous reactivity across both electrodes (e.g., lithium metal plating on the anode surface, fracture of the cathode particles, etc.) [1]–[3]. A fundamental study of the processes responsible for battery degradation is a necessary step toward designing next-generation LIBs and is a critical research priority for the U.S. Department of Energy. Here, we demonstrate that high charging currents lead to chemical, structural, and morphological changes in the graphite anode that spans the atomic-scale to the bulk-scale. As the integrity of the graphite host is critical to lithium-ion cell performance, our findings regarding the degradation mechanism provide the essential knowledge to enable the development of viable fast-charging LIBs.Our strategies to study the graphite anode degradation are based on advanced analytical electron microscopy and diffraction. We focus on the modifications that occur in the material when subjected to charging rates up to 6C (i.e., 10 minutes to full charge). The characterization is performed post-mortem across different length-scales on as-prepared electrodes and electrodes harvested from cycled cells (represented in Figure 1). At the bulk-scale, we use scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to probe the morphological and chemical changes in cross-sections of the graphite anode samples. At the nano- and atomic-scale, we use advanced transmission electron microscopy (TEM) and diffraction techniques to reveal changes in both the nano-scale chemistry and the graphite microstructure. Key findings from this investigation include the morphological changes to the graphite particles at the micron-scale and the partial-filling of the inter- and intra-particle gaps with solid electrolyte interphase (SEI) compounds at the meso-scale. Further, at the nano- to atomic-scale, we observe greater disorder and amorphous character in the graphite near the internal pore surfaces when compared to that of the bulk graphite regions. The nature of the lattice disorder, and the characterization methods employed to examine this disorder, will be discussed. Additional supporting evidences of graphite disorder and phase change from Raman spectroscopy and X-ray diffraction studies will also be presented. Acknowledgements: SP acknowledges support from the U.S. Department of Energy Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the U. S. Department of Energy under contract number DE‐SC0014664. This work was carried out in part in the Materials Research Laboratory Central Research Facilities, University of Illinois. DA and MTFR acknowledge support from DOE’s Vehicle Technologies Office. This document has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. References : [1] C. Heubner, K. Nikolowski, S. Reuber, M. Schneider, M. Wolter, and A. Michaelis, “Recent Insights into Rate Performance Limitations of Li-ion Batteries,” Batter. Supercaps, Nov. 2020.[2] M.-T. Fonseca Rodrigues et al., “Lithium Acetylide: A Spectroscopic Marker for Lithium Deposition During Fast Charging of Li-Ion Cells,” ACS Appl. Energy Mater., vol. 2, no. 1, pp. 873–881, Jan. 2019.[3] Y. Yang et al., “Quantification of Heterogeneous Degradation in Li-Ion Batteries,” Adv. Energy Mater., vol. 9, no. 25, p. 1900674, Jul. 2019. Figure 1

(Energy Technology Division Graduate Student Award sponsored by Bio-Logic) Understanding Charge Transport for Current and Future Electrochemical Energy Storage Technologies

Advances in electrochemical energy storage are key for the integration of intermittent wind and solar energy sources into the grid, widespread adoption of electric vehicles, and development of new safe and reliable consumer devices. For grid, transportation, and electronic energy storage markets, each application has distinct needs. Therefore, developing battery technology for emerging and wide-spread applications demands greater understanding of the complex chemical and electrochemical processes that occur within rechargeable batteries. Electron transfer and ion transport are the foundation of battery function where the capacity, loaded voltage and current define the practical energy and power delivery of the system. During operation, repetitive addition and removal of electrons and ions can lead to structural change within the electrode and interfacial formation that can dramatically impact electrochemical outcomes. Thus, structural, chemical, and electrochemical characterization during operation is critically important for next generation electrochemical energy storage technologies. The research efforts highlighted in this talk use multiple advanced characterization techniques, including operando methods, to probe charge transport properties, structural changes, and interfacial evolution in multiple rechargeable battery systems. Specifically, spatiotemporal x-ray fluorescence mapping was used to quantify elemental composition near the electrode and in the electrolyte of operando cells. Isothermal microcalorimetry was used to determine heat evolution due to parasitic or decomposition reactions operando. X-ray absorption spectroscopy enabled structure and oxidation state elucidation in the absence of long-range order. X-ray diffraction was employed to track phase changes of distinct electroactive materials. Using advanced characterization, these research efforts provide insight into electron transfer and ion transport properties and their impact on application relevant outcomes (resistance, cycle life, delivered capacity) of electrochemical energy storage technologies.

How eco‐efficient are electric vehicles across Europe? A regionalized life cycle assessment‐based eco‐efficiency analysis

AbstractSustainable transportation is at the hearth of the United Nation's Sustainable Development Goals (SDGs) and is directly linked to many SDGs including SDG3 (good health and well‐being), SDG11 (sustainable cities and societies), SDG 7 (clean energy), SDG13 (climate), and SDG 12 (sustainable production and consumption). European countries have been promoting a widespread adoption of electric vehicles to achieve SDGs through resilient, technology‐driven, and human‐centric mobility. However, potential environmental benefits of electric vehicles depend on various regional factors such as the fuel efficiency and source of electricity generation. At the same time, the economic benefits of mobility to the economy are an important factor for evaluating the relative performance of electric vehicles. To this end, this research paper presents the first empirical analysis of the regionalized eco‐efficiency assessment of electric vehicles across Europe. We developed an integrated regionalized eco‐efficiency performance score, by employing life cycle assessment and principal component analysis techniques to assess the eco‐efficiency performance of electric vehicles in Europe. Considering the energy mix for electricity generation, three environmental indicators (carbon footprint, water consumption, and energy use) and one economic (contribution to national gross domestic product) indicator were used to compute the eco‐efficiency scores for 28 European countries. The eco‐efficiency scores for each corresponding country were calculated, compared, and clustered in as high, medium, and low eco‐efficiency score countries. The clvalid package of R software's archive network is used to determine the optimal number of clusters for the EES dataset. The results of the comparative study show that Denmark, Germany, Italy, Portugal, and Spain have a competitive advantage in eco‐efficiency performance compared to the other European countries. The regionalized distribution of the eco‐efficiency performance shows that the countries with the highest ecoefficiency score are located on the west side of Europe. Researches and policymakers can benefit from the applied methodology as well as the results to provide country‐specific investment policies to achieve higher benefits towards a transition to electric mobility in Europe.

Self-Rechargeable Battery Vehicle

Widespread adoption of electric vehicles will relieve us from problems such as environmental pollution, global warming and oil dependency. However, theusage of EV is relatively low in spite of many governments implementing strong promotion policies. This paper presents a understandable review of studies on consumer preferences for EV, aiming to better inform policy-makers and give direction to further research. First, we compare the psychological and economic approach towards this topic, followed by a conceptual work of EV preferences which is then implemented to organise our review. We also consider the modelling techniques applied in the selected studies. Estimates of consumer preferences for financial, technical, infrastructure and policy attributes are then considered. A categorisation of main factors for consumer preferences into groups such as socio-economic variables, psychological factors, mobility condition, social influence, etc. is then made and their impacts are briefly explained. Finally, we discuss a research agenda to improve EV consumer preference studies and give suggestions for further research.

Economies of scale in battery cell manufacturing: The impact of material and process innovations

One key lever to reduce high battery cost, a main hurdle to comply with CO2 emission targets by overcoming generation variability from renewable energy sources and widespread electric vehicle adoption, is to exploit economies of scale in battery production. In an industry growth currently supported by subsidies, cost-efficient battery plant sizes are vital for the establishment of a self-sustaining industry and a transition into a long-term climate-neutral society. For optimal plant sizing, no consensus has yet been achieved in the battery literature and a detailed analysis of economies of scale is unavailable. To close this gap, a process-based cost modeling approach is taken that reflects the determinants of economies of scale. In state-of-the-art, minimum viable plant sizes are demonstrated to be below 2 GWh year−1 but may exceed 15 GWh year−1 in the future. This study finds that economies of scale are related to the capacity of the roll-to-roll processes in electrode manufacturing and can be maximized if the respective equipment operates at its capacity limit. This capacity depends on materials, cell design and roll-to-roll process parameters. Since these parameters improve over time, increased plant sizes will become necessary to achieve cost-efficient production levels. Required plant investments are found to decrease on a per GWh basis, whereas significantly increased funds will become necessary to reach efficient plant sizes in the future. Finally, implications are presented that support future battery cost reductions and a self-sustaining market breakthrough of battery-powered products.

Quantification of heterogeneous, irreversible lithium plating in extreme fast charging of lithium-ion batteries

Realization of extreme fast charging (XFC, ≤15 minutes) of lithium-ion batteries is imperative for the widespread adoption of electric vehicles.

Grid Impact of Electric Vehicle Fast Charging Stations: Trends, Standards, Issues and Mitigation Measures - An Overview

With growing concern on climate change, widespread adoption of electric vehicles (EVs) is important. One of the main barriers to EV acceptance is range anxiety, which can be alleviated by fast charging (FC). The main technology constraints for enabling FC consist of high-charging-rate batteries, high-power-charging infrastructure, and grid impacts. Although these technical aspects have been studied in literature individually, there is no comprehensive review on FC involving all the perspectives. Moreover, the power quality (PQ) problems of fast charging stations (FCSs) and the mitigation of these problems are not clearly summarized in the literature. In this paper, the state-of-the-art technology, standards for FC (CHAdeMO, GB/T, CCS, and Tesla), power quality issues, IEEE and IEC PQ standards, and mitigation measures of FCSs are systematically reviewed.

Mesoscale Electrode Analytics for Fast Charging

Fast charging of lithium-ion batteries is paramount toward widespread adoption of electric vehicles. Fast charging, however, poses safety concerns due to the occurrence of lithium plating and local thermal excursions. Preserving the thermal safety, performance and life of LIBs at such operating extremes necessitates a thorough understating of the thermal and degradation interactions emanating at the electrode level. In this work, the electrode-level implications of thermal and electrochemical characteristics of Li-ion cells during fast charge conditions is examined. Suggestions for improvement in fast charging capabilities via electrode engineering are made.

Synthesis of LiNiO2 at Moderate Oxygen Pressure and Long-Term Cyclability in Lithium-Ion Full Cells.

The widespread adoption of electric vehicles necessitates higher-energy-density and longer-life cathode materials for Li-ion batteries. LiNiO2 offers a higher energy density at a lower cost than other high-Ni-content cathodes containing additional transition-metal ions. However, detrimental phase transformations and impedance growth, resulting from structural defects formed during synthesis, lead to poor cyclability and limit the practical viability of LiNiO2. Herein, we demonstrate a considerably improved cycle life for LiNiO2 by synthesizing it under a pressurized oxygen environment. The capacity retention in pouch-type full cells with a graphite anode after 1000 cycles is increased from 59 to 76% by applying a mere 1.7 atm of oxygen pressure during the synthesis of LiNiO2. With iodometric titration and inductively coupled plasma optical emission spectroscopy analysis, we provide clear evidence that oxygen pressure during synthesis reduces the occurrence of lattice oxygen vacancies and increases the content of Ni3+ in LiNiO2, improving its structural integrity and cyclability. Post-mortem analysis of the cycled cathodes provides insights into the sources of degradation occurring during long-term cycling. This work demonstrates a practically viable, synthetic approach combined with doping and coating to achieve improved performance with high-Ni layered oxide materials. Furthermore, this work represents the first report of extended cycling of LiNiO2 in pouch full cells with graphite anode and will, therefore, serves as an important benchmark for future research on LiNiO2.

Support Structure

Flexible and Cost-Effective Power Infrastructure is Integral to Support the Widespread Adoption of Electric Vehicles

Two-Stage Fuzzy Logic Inference Algorithm for Maximizing the Quality of Performance under the Operational Constraints of Power Grid in Electric Vehicle Parking Lots

The widespread adoption of electric vehicles (EVs) has entailed the need for the parking lot operators to satisfy the charging and discharging requirements of all the EV owners during their parking duration. Meanwhile, the operational constraints of the power grids limit the amount of simultaneous charging and discharging of all EVs. This affects the EV owner’s quality of experience (QoE) and thereby reducing the quality of performance (QoP) for the parking lot operators. The QoE represents a certain percentage of the EV battery required for its next trip distance; whereas, the QoP refers to the ratio of EVs with satisfied QoE to the total number of EVs during the operational hours of the parking lot. This paper proposes a two-stage fuzzy logic inference based algorithm (TSFLIA) to schedule the charging and discharging operations of EVs in such a way that maximizes the QoP for the parking lot operators under the operational constraints of the power grid. The first stage fuzzy inference system (FIS) of TSFLIA is modeled based on the real-time arrival and departure probability density functions in order to calculate the aggregated charging and discharging energies of EVs according to their next trip distances. The second stage FIS evaluates several dynamic and uncertain input parameters from the electric grid and from EVs to distribute the aggregated energy among the EVs by controlling their charging and discharging operations through preference variables. The feasibility and effectiveness of the proposed algorithm are demonstrated through the IEEE 34-node distribution system.

Comparing Devices for Concurrent Measurement of AC Current and DC Injection during Electric Vehicle Charging

Widespread adoption of electric vehicles (EVs) requires additional safety countermeasures to prevent DC injection from EVs into the AC grid via Electric Vehicle Supply Equipment (EVSE). Moreover, for energy purchase, and even more so for vehicle-to-grid (V2G) services, the EVSE must conduct high precision bidirectional power and energy measurements. This paper introduces operating principles, structure, performance, and cost comparison of three current sensing technologies—current transformer, shunt and fluxgate—for metering and protection within an EVSE, concluding with recommendations among those sensors for the most beneficial applications concerning EV charging.

Effects of charging rates on LiNi0.6Mn0.2Co0.2O2 (NMC622)/graphite Li-ion cells

Effects of different fast charging rates are studied on the capacity fading, electrode microstructural changes and electrolyte changes in LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622)/graphite pouch cells. Enabling fast charging capability of lithium-ion battery is of great importance to widespread adoption of electric vehicles. Increasing the charging rates from state-of-the-art 2C (30 min) to 6C (10 min) requires deep understanding on the cell aging mechanism. In this study, 400 mAh pouch cells are cycled at 1C, 4C and 6C charging rates with 1C discharging rate. Capacity fading, cathode structural changes, Li inventory loss, electrolyte composition changes and Li plating on graphite electrodes are thoroughly studied by various characterization techniques. The rapid capacity fading in cells at 6C charging rate is mainly due to Li inventory loss from cathode structure and metallic Li plating on graphite electrode at higher charging rate. Post-mortem analysis also revealed changes in electrolyte such as increased salt molarity and transesterification during fast charging.

A Case Study to Identify the Hindrances to Widespread Adoption of Electric Vehicles in Qatar

The adoption of electric vehicles (EVs) have proven to be a crucial factor to decreasing the emission of greenhouse gases (GHG) into the atmosphere. However, there are various hurdles that impede people from purchasing EVs. For example, long charging time, short driving range, cost and insufficient charging infrastructures available, etc. This article reports the public perception of EV-adoption using statistical analyses and proposes some recommendations for improving EV-adoption in Qatar. User perspectives on EV-adoption barriers in Qatar were investigated based on survey questionnaires. The survey questionnaires were based on similar studies done in other regions of the world. The study attempted to look at different perspectives of the adoption of EV, when asked to a person who is aware of EVs (technical respondents—people studying/working at universities/research centers and policy makers) or a person who may or may not be aware of EVs (non-technical respondents—people working in banks, governments and private non-academic organizations, etc.). Cumulative survey responses from the two groups were compared and analyzed using two-sample t-test statistical analysis. Detailed analyses showed that—among various major hindrances—raising of public awareness of such greener modes of transportation, the availability of charging options in more places and policy incentives towards EVs would play a major role in EV-adoption. The authors provide recommendations that—along with government incentives—could help make a gradual shift to a greater number of EVs convenient for people of Qatar. The proposed systematic approach for such a study and analysis may help in streamlining research on policies, infrastructures and technologies for efficient penetration of EVs in Qatar.

Challenges and Strategies for Fast Charge of Li‐Ion Batteries

AbstractLong charging time for Li‐ion batteries is a critical obstacle for the widespread adoption of electric vehicles, especially when compared with the rapid refueling of traditional internal combustion engine vehicles. Fast charging results in accelerated performance degradation and low energy efficiency for Li‐ion batteries. The batteries adopted in the present electric vehicle market are mainly based on chemistry consisting of a graphite anode and a layered lithium transition‐metal oxide cathode. The fast‐charging capability of such batteries is limited by Li plating on the graphite anode and structural instability of the layered lithium transition‐metal oxide cathode. In this Minireview, the challenges and possible solutions to these fast charge problems are reviewed at both the materials and cell levels.

Uncertainty-aware state estimation for electrochemical model-based fast charging control of lithium-ion batteries

Fast charging capability is considered a critical factor for the widespread adoption of electric vehicles. High charging currents can, however, severely affect battery health due to the danger of metallic lithium deposition on the anode and consequent degradation reactions. The charging speed should therefore be limited with respect to battery temperature, state of charge, and cell design, governing the onset point of lithium plating. Electrochemical models are a suitable tool providing continuous estimates of the anode potential as the main lithium plating indicator while covering a wide operational range. In this article, we present a novel charging control scheme based on a real-time capable simulation framework with adjustable model resolution. A profound investigation of error sources and modeling uncertainties motivates online state corrections towards a lower bound of the anode potential, which are realized by selective adjustments of the lithium distribution within electrode particles based on the full cell voltage error. Simulations of controlled and conventional CC charging profiles indicate the importance of continuously adapting the charging power for different operating conditions. Further, simulated state and parameter distortions as they might result from initialization and parameterization errors show that our estimation strategy can mitigate the risk of unsafe control operations.