Anode potential controlled charging prevents lithium plating Rangarajan, Sobana P; Barsukov, Yevgen; Mukherjee, Partha P
Journal of materials chemistry. A, Materials for energy and sustainability,
01/2020, Volume:
8, Issue:
26
Journal Article
Peer reviewed
We report a novel anode potential controlled charging strategy for lithium-ion cells which eliminates lithium plating under most aggressive conditions, such as at low temperatures. This is applicable ...for lithium-ion cells with a graphite anode irrespective of the form factor, capacity or cathode chemistry. This new charging strategy leads to a seven-fold increase in cycle life and a concomitant improvement in the electrochemical performance. Conventional charging shows copious lithium plating swiftly followed by cell failure due to accelerated increase in the anode resistance. The anode potential controlled charging strategy, based on a three-electrode cell construction, exhibits minimal increase in the anode resistance and shows no signs of lithium plating in operational extremes. Optical micrographs and high-resolution scanning electron images confirm that the graphite anode in the conventionally charged Li-ion cell undergoes significant loss in porosity resulting in massive underlithiation and dramatic capacity fading. The degradation rate in the anode is decelerated in anode potential controlled charging by ensuring that plating potential is not reached and improving ion transport in the anode even at low temperatures due to the absence of decomposition products that would have formed during plating.
We report a novel anode potential controlled charging strategy for lithium-ion cells which eliminates lithium plating under most aggressive conditions, such as at low temperatures.
A three-electrode cell can be a useful tool for measuring electrode-level and cell-level electrochemical characteristics, such as the impedance response and potential variations in lithium-ion cells. ...In this paper, a reliable three-electrode coin cell setup is introduced, which improves the stability and accuracy of electrochemical measurements by modifying the electrode alignment and employing Li4Ti5O12 as a reference electrode. An important highlight is the ability to obtain impedance evolution characteristics at different depth of discharge (DOD) for an individual electrode and the full cell based on both the frequency response analysis and the carrier function Laplace transform characteristics. The reliability of the proposed modified three-electrode coin cell setup has been validated by analyzing the impedance response of symmetric and full cells, and the voltage profiles of the full cell along with the positive/negative electrode contributions. The importance of the resistance contributions from the negative and positive electrodes to the full cell impedance evolution at different DOD is highlighted.
The introduction of Li-ion batteries in 1991 created a tremendous change in the handheld devices landscape. Since then, the energy stored and put to use in palm-sized electronic devices has ...quadrupled. Devices are continuously getting more power hungry, outpacing battery development. Written by leading engineers in the field, this cutting-edge resource helps you overcome this challenge, offering you an insightful overview and in-depth guide to the many varied areas of battery power management for portable devices. You find the latest details on optimizing charging circuits, developing battery gauges that provide the longest possible run-time while ensuring data protection, and utilizing safety circuits that provide multiple independent levels of protection for highly energetic batteries. This unique book features detailed design examples of whole systems, providing you with the real-world perspective needed to put this knowledge into practice. You get the state-of-the-art know-how you need to perfect your device designs, helping you make them strong competitors in the fast-growing portable device marketplace.
The performance and safety of lithium-ion batteries are plagued by several diverse, nonlinear aging mechanisms influenced by the electrochemical thermal interactions at the electrodes, usage history, ...and operating conditions. Understanding and deconvoluting the fundamental reaction mechanisms responsible for electrode degradation are key for developing technologies in Li-ion battery diagnostics and prognostics. Hence, there exists a need for high-precision operando techniques to investigate and characterize distinct electrode degradation modes over a gamut of operational variability. Cells embedded with a stable, nonpolarizable reference electrode offer an in situ and operando tool to decouple the complex electrochemical interplay between the electrode pair by measuring individual electrode responses simultaneously with the cell response in the time and frequency domains. This perspective comprehensively looks at 3-electrode (3ε) analytics as a versatile toolbox, highlighting recent techniques and parameters developed with an emphasis on degradation diagnostics and control strategies that is expected to drive the futuristic design of battery management systems.
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A key to understanding the coupled electrochemical and transport processes in Li-ion batteries is to distinguish the complex interactions between the electrode pair. In this study, an in operando ...impedance based diagnostics for a three-electrode Li-ion pouch cell configuration is presented in order to study the individual electrode kinetics under varying operating temperatures and depths of discharge. The electrochemical processes including intercalation, diffusion, and interfacial reactions occur at different timescales. Impedance analytics allows estimating the resistances and activation energies of different processes to identify the limiting mechanisms in each electrode. It was found that at −5°C, the effect of staging in the graphite electrode manifests as a piece-wise dependence of the pore resistance and the double layer capacitance in the anode. The dense and highly ordered stages 1, 2 of graphite exhibit higher ionic resistance than the disordered (2L,3L, and 4L) stages at −5°C, due to the added contribution of pore transport resistance at higher depths of discharge.
In operando signature and quantification of lithium plating Rangarajan, Sobana P.; Barsukov, Yevgen; Mukherjee, Partha P.
Journal of materials chemistry. A, Materials for energy and sustainability,
2019, Volume:
7, Issue:
36
Journal Article
Peer reviewed
Lithium plating is a critical challenge for lithium intercalation battery chemistry, especially at high charge rates and high states of charge leading to reduced cycle life, capacity loss, and safety ...concerns. The anode-centric process of metallic lithium deposition can be identified by monitoring the anode potential in a full cell. In this study an in operando , three-electrode Li-ion pouch cell construct is proposed to probe and quantify lithium plating over a gamut of operational variability, combined with a comprehensive analysis including electrochemical, microscopy and spectroscopy signatures. Different regimes of capacity fade over cycling are identified with respect to the relative extent of lithium plating based on the plating energy as a descriptor. This study reveals the existence of a critical rate where the degradation due to lithium plating is minimal, which is a manifestation of the synergy between the kinetic processes and heat generation signatures. Different morphologies of lithium plating were observed, such as, localized agglomeration predominantly at rates exhibiting higher extent of plating, while diffuse characteristics at rates with lower amount of plating. The propensity for lithium plating and plating induced failure are found to increase with aging even at lower charge rates. This study comprehensively proffers the stochastic nature of the lithium plating process with operational variability.
Fast charging of lithium-ion cells is key to alleviate range anxiety and improve the commercial viability of electric vehicles, which is, however, limited by the propensity of lithium plating. The ...plated lithium can grow dendritically and may cause internal short and increase the risk of thermal runaway. In this study, a novel anode potential control strategy using a battery management system (BMS) has been demonstrated to enable fast charging in commercial pouch cells without lithium plating. Operando anode potential measurement using a 3-electrode configuration allows monitoring the occurrence of lithium plating. A novel 3-electrode cell analytics was developed to delineate the irreversible and irretrievable contributions to the total capacity loss and identify electrode-specific degradation mechanisms. The BMS algorithm dictates the charging current to maintain a positive anode potential and prevents lithium plating on the anode but fails to sufficiently control the cathode operating potential leading to irretrievable capacity loss. Operating the cell in conditions favorable to the anode may contrarily lead to cathode degradation and subsequent cell failure. Morphological and electrochemical characterizations reveal minimal anode degradation and a 2× higher cathode-capacity loss in the BMS-controlled cells. The baseline cell, not enabled with the BMS anode potential control strategy, exhibits extensive lithium deposition in the anode resulting in 7× higher anode-capacity loss. This study discovers the role of cathode-induced cell failure even when the anode-centric lithium plating is prevented and suggests pathways toward future BMS algorithm development enabling Li-ion cell operation under extremes.
Fast charging of lithium-ion cells is key to alleviate range anxiety and improve the commercial viability of electric vehicles, which is, however, limited by the propensity of lithium plating.
Mesoscale Anatomy of Dead Lithium Formation Tewari, Deepti; Rangarajan, Sobana P; Balbuena, Perla B ...
Journal of physical chemistry. C,
03/2020, Volume:
124, Issue:
12
Journal Article
Peer reviewed
Lithium metal anodes are an attractive option for next-generation batteries because of high gravimetric and volumetric energy densities. The formation of dendritic morphology of electrodeposition ...during charging, however, poses safety concerns, which, in particular, have been a focus of intense research. The formation of “dead lithium” with successive cycling, on the other hand, has been relatively unexplored as the deterioration in performance is gradual. Dead lithium is the fragment of lithium that is detached from the lithium electrode during electrodissolution or stripping. In this study, the mesoscale underpinnings of dead lithium formation via a synergistic computational and experimental approach are presented. The mechanistic focus centers on the morphological evolution of the lithium electrode–electrolyte interface and the relative quantification of dead lithium formation under a range of operating temperatures and currents. This study reveals that the amount of dead lithium formed during stripping increases with decreasing current and increasing temperatures. This finding is in direct contrast to the operating conditions that lead to dendritic deposition during charging, i.e., at higher currents and lower temperatures. During stripping, more dead lithium is formed when the interface has thin narrow structures. The ionic diffusion and self-diffusion of lithium at the interface play a key role in the evolution of narrow structures at the interface. Therefore, more dead lithium is formed when diffusive processes are facilitated compared to the oxidative reaction at the interface.
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9.
signature and quantification of lithium plating Rangarajan, Sobana P; Barsukov, Yevgen; Mukherjee, Partha P
Journal of materials chemistry. A, Materials for energy and sustainability,
09/2019, Volume:
7, Issue:
36
Journal Article
Peer reviewed
Lithium plating is a critical challenge for lithium intercalation battery chemistry, especially at high charge rates and high states of charge leading to reduced cycle life, capacity loss, and safety ...concerns. The anode-centric process of metallic lithium deposition can be identified by monitoring the anode potential in a full cell. In this study an
in operando
, three-electrode Li-ion pouch cell construct is proposed to probe and quantify lithium plating over a gamut of operational variability, combined with a comprehensive analysis including electrochemical, microscopy and spectroscopy signatures. Different regimes of capacity fade over cycling are identified with respect to the relative extent of lithium plating based on the plating energy as a descriptor. This study reveals the existence of a critical rate where the degradation due to lithium plating is minimal, which is a manifestation of the synergy between the kinetic processes and heat generation signatures. Different morphologies of lithium plating were observed, such as, localized agglomeration predominantly at rates exhibiting higher extent of plating, while diffuse characteristics at rates with lower amount of plating. The propensity for lithium plating and plating induced failure are found to increase with aging even at lower charge rates. This study comprehensively proffers the stochastic nature of the lithium plating process with operational variability.
In operando
detection and quantification of lithium plating is critical toward understanding the deleterious consequences under operational extremes in Li-ion batteries.
Lithium plating is an anode-centric degradation process occurring in lithium-ion batteries resulting in irreversible capacity loss and cell failure. Temperature plays a critical role in improving the ...kinetics and transport, reducing lithium plating propensity. This study quantitively probes the evolution of plating with aging under temperature extremes in commercial Li-ion cells. Plating energy is proposed as a unique descriptor to quantify the extent of lithium plating and state of the electrode using operando analytics at any operating condition. Cells operated at temperature extrema (high/low) experience rapid capacity fade accompanied by a significant rise in anode impedance and exhibit plating energies greater than 1 Wh. Unfavorable intercalation kinetics at low temperatures and favorable solid electrolyte interphase (SEI) kinetics at high temperatures exacerbate anode impedance. These kinetically disparate manifestations on anode impedance adversely impact the interfacial overpotential and reversibility of plating, resulting in localized deposits and preferential stripping, ultimately promoting cell failure.
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•Quantifying lithium plating holds the key to fast charging of EVs•More plating is observed with increasing anode impedance at temperature extremes•Plating energies greater than 1 Wh are associated with cell failure•Highly irreversible plating is observed at cells with >1 Wh plating energy
Understanding the quantitative evolution of lithium plating with aging at temperature extremes is crucial to design failure-aware battery management systems. Here, Rangarajan et al. look at the threshold amount of lithium plating observed before the cell experiences accelerated failure at operational extremes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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