Surface structural disordering in graphite upon lithium intercalation/deintercalation

Sethuraman, Vijay A.; Hardwick, Laurence J.; Srinivasan, Venkat; Kostecki, Robert

doi:10.1016/j.jpowsour.2009.12.034

Cited by 279 publications

(221 citation statements)

References 32 publications

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“…[14][15][16][17][18][19] This wide range can be attributed to different kinds of graphite used in these studies in addition to different techniques used to extract the diffusion coefficient. Model predictions would suggest that for the lower value of diffusion coefficient (1.0 × 10 −14 m 2 /s) particle cracking during delithiation becomes likely at moderate C-rates (1 C based on the theoretical capacity of graphite), for particle of 14 μm diameter.Although studies have suggested that graphite disorder increases with cycling, 20 and that the electrode can undergo mechanical damage, 21 literature studies do not show evidence of graphite particles themselves cracking. While modeling studies have shown that graphite cracking is possible, no experimental studies have been reported that indicate this mode of degradation at the particle scale, suggesting a disparity between the model predictions and the experimental observation.…”

mentioning

confidence: 98%

Examination of Graphite Particle Cracking as a Failure Mode in Lithium-Ion Batteries: A Model-Experimental Study

Takahashi

Srinivasan

2015

J. Electrochem. Soc.

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104

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Capacity fade in lithium-ion batteries remains an area of active research, with failure of the graphite anode thought to be an important contributor. While the formation of the solid electrolyte interphase and the subsequent loss of cyclable lithium have been well studied, mechanical degradation remains an area where ambiguity remains. While there appears to be little experimental evidence that suggest that macroscopic particle cracking occurs, mathematical models have suggested that this phenomenon is likely. The goal of this paper is to clarify this ambiguity by combining experimental cycling, mathematical stress modeling, and post-mortem microscopy. We experimentally determine an average diffusion coefficient of lithium in graphite using a thin-layer electrode and use this information in a diffusion-induced stress model. Our results suggest that cracking is not likely during lithiation due to the proximity of equilibrium potential to the cutoff potential. On delithiation, at 25 • C, even at 30 C rate cracking is unlikely while at −10 • C, a rate of 10 C can lead to particle cracking. By extrapolating the results of the thin-layer electrode to a thick porous electrode, we found that graphite cracking is unlikely to occur during typical vehicle operations. In recent years, there have been numerous studies on lithium-ion batteries for vehicle applications. [1][2][3][4][5] Of particular interest are the various degradation mechanisms encountered when operating the battery under severe conditions (i.e., wide temperature ranges and high Crates) typical for vehicle applications.6 One likely degradation mechanism is the mechanical breakdown of the active materials. Lithium insertion (or extraction) into (or out of) the lattice of the active materials causes volume change (expansion and contraction), resulting in stress generation and possible fracture of the particles. For example, in graphite anodes, crack generation can expose new surfaces to the electrolyte, leading to further formation of the solid electrolyte interphase (SEI) 7,8 and/or particle isolation from the electronic network, leading to impedance growth, loss of cyclable lithium, and capacity fade.Mathematical models, based on diffusion-induced stress generation, have been used to investigate particle fracture and have suggested that graphite particle cracking is likely under certain conditions. [9][10][11][12][13] For the diffusion-induced stress model, diffusion coefficient in solid phase is a key parameter to determine the concentration gradient in the particle, which in turn affects the stress generated.9 However, there is a wide disparity in the measured diffusion coefficient of lithium in graphite, ranging from 10 −16 to 10 −11 m 2 /s. [14][15][16][17][18][19] This wide range can be attributed to different kinds of graphite used in these studies in addition to different techniques used to extract the diffusion coefficient. Model predictions would suggest that for the lower value of diffusion coefficient (1.0 × 10 −14 m 2 /s) particle cracking durin...

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mentioning

confidence: 98%

Examination of Graphite Particle Cracking as a Failure Mode in Lithium-Ion Batteries: A Model-Experimental Study

Takahashi

Srinivasan

2015

J. Electrochem. Soc.

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104

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“…Inspection of Fig. 7f and j also reveal an additional peak at a potential of 3.45 V. Based on the information provided within [47,48], this new peak is most likely resulting from a phase change in the earlier lithiation process of the graphite electrode. This decrease of the OCV is directly related to the increase in energy capacity.…”

Section: Duty-cycle Studymentioning

confidence: 82%

“…At 0% SOC, the graphite electrode is almost completely delithiated. During charging, Li + ions intercalate into the graphite layers and the material transitions through several phases as the lithium content within the material increases [47,48]. One of these phase transitions is indicated in the peak around a full cell potential of 3.52 V in Fig.…”

Section: Duty-cycle Studymentioning

confidence: 98%

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

Kellner

Worwood

Barai

et al. 2018

Journal of Energy Storage

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A B S T R A C TThe long-term behaviour of lithium ion batteries in high-performance (HP) electric vehicle (EV) applications is not well understood due to a lack of suitable testing cycles and experimental data. As such a generic HP duty cycle (HP-C), representing driving on a race track is validated, and six NMC graphite cells are characterised with respect to cycle-life. To enable a comparison between the HP-EV environment and conventional road driving, two test groups of cells are subject to an experimental evaluation over 200 duty cycles that includes a representative HP-C and a standard duty cycle from the IEC 62660-1 standard (IECC). After testing, both test groups display increased energy capacity, increased pure Ohmic resistance, lower charge transfer resistance an extended OCV operating window. The changes are more pronounced for cells subject to the HP-C. Based on capacity tests, Electrochemical Impedance Spectroscopy (EIS), pseudo-OCV tests, and Pulse Multisine Characterisation, it is concluded that the changes in cell characteristics are most likely caused by cracking of the electrode material caused by high electrical current pulses. With continued cycling, cells cycled with the HP-C are expected to show degradation at an increased rate due to raised temperatures, and more pronounced electrode cracking.

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“…During charge/discharge cycling or storage of LIBs, aging effects may occur [7]. Mechanical degradation like graphite exfoliation or surface structural disordering leads to loss of mobile lithium or self-discharge [8][9][10][11]. One of the main reasons for exfoliation is the cointercalation of solvated lithium ions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Electrochemical Behavior of Nanostructured Copper Particles on Graphite for Application in Lithium Ion Batteries

Licht

Homeyer

Bösebeck

et al. 2015

Zeitschrift Für Physikalische Chemie

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Graphitic materials are currently the state-of-the-art anode materials for lithium ion secondary batteries. By chemical modification, the electrochemical performance of the pristine materials can be improved. In this paper we report on the preparation of nanostructured copper particles on graphite by thermal decomposition of copper formate. With this technique a novel, simple and low cost method for a homogeneous deposition of nanostructured copper particles on graphite was established. Different amounts of copper were realized and their influence on the electrochemical behavior of the active material was investigated.The copper particles had a size distribution between 50 nm and 300 nm. Electrochemical measurements displayed an improved performance of the synthesized composite material compared to the pristine material. Cyclic voltammetry showed a suppressed cointercalation of solvated lithium and an increased formation of the solid electrolyte interphase (SEI). Battery cycling demonstrated an increased discharge capacity and cycling stability.

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Surface structural disordering in graphite upon lithium intercalation/deintercalation

Cited by 279 publications

References 32 publications

Examination of Graphite Particle Cracking as a Failure Mode in Lithium-Ion Batteries: A Model-Experimental Study

Examination of Graphite Particle Cracking as a Failure Mode in Lithium-Ion Batteries: A Model-Experimental Study

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

Synthesis and Electrochemical Behavior of Nanostructured Copper Particles on Graphite for Application in Lithium Ion Batteries

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