A Dilatometric Study of Lithium Intercalation into Powder-Type Graphite Electrodes

Hahn, Matthias; Buqa, Hilmi; Ruch, Patrick; Goers, Dietrich; Spahr, Michael E.; Ufheil, Joachim; Novák, Petr; Kötz, R.

doi:10.1149/1.2940573

Cited by 103 publications

(71 citation statements)

References 18 publications

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“…Considering that volume expansion of LiCoO 2 is negligible, the thickness change of the cell was attributable to the anode. The graphite electrode thickness after the lithiation increased to about 10%, which is consistent with reported values [10,20]. During delithiation, the graphite electrode showed the decrement in the thickness, however, did not return to its initial thickness.…”

Section: Resultssupporting

confidence: 90%

Polymer microsphere embedded Si/graphite composite anode material for lithium rechargeable battery

Hwang

Cho

Kim

2010

Electrochimica Acta

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Section: Resultssupporting

confidence: 90%

Polymer microsphere embedded Si/graphite composite anode material for lithium rechargeable battery

Hwang

Cho

Kim

2010

Electrochimica Acta

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“…Specifically, we know that most of the peaks present in dV/dQ are due to the graphite electrode and hypothesize that the analogous peaks in d 2 ε/dQ 2 also represent graphite transitions because the graphite electrode has more stages and exhibits an order of magnitude larger expansion than LCO. [15][16][17] The last peak in both the strain and voltage curves at around 0.46 Ah is a known exception and belongs to an LCO electrode transition. 5 While peaks in Figure 2c are visually clear, there are multiple options for quantifying them.…”

Section: Resultsmentioning

confidence: 99%

Strain Derivatives for Practical Charge Rate Characterization of Lithium Ion Electrodes

Schiffer

Cannarella

Arnold

2015

J. Electrochem. Soc.

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During battery use, electrode materials are known to expand and contract in repeatable patterns, and this strain has been previously correlated with battery properties such as state of charge and state of health. In this study, we show that the second derivative of strain, d 2 ε/dQ 2 , is mathematically proportional to dV/dQ within an electrode stage. We also experimentally quantify peaks in the strain curves for electrode stage transitions at practical charge rates of up to C/2 and confirm that transitions are visible in the practical scenario of discharging at the higher rate of 1C. Moreover, the location of the transition measured by d 2 ε/dQ 2 changes by less than 10% from 0.05 C to 0.5 C, but the transition measured with dV/dQ decreases by more than 15% from 0.05 C to 0.3 C, demonstrating the reliability of strain to measure electrode transitions at moderate charge rates. We also note that d 2 ε/dQ 2 exhibits similar peak shifts as those expected in dV/dQ as the cell ages. Our derivations for the model system of graphite and lithium cobalt oxide can be generalized to other battery systems and used to characterize materials at practical charge rates impossible with only voltage. Lithium ion batteries are a popular choice for energy storage due to their high ratio of energy capacity to size and their low rate of self-discharge.1 Unfortunately, batteries are difficult to characterize because they are essentially isolated systems with many reactions and processes occurring internally. Imaging the internal reactions and materials during battery operation is impractical, and very few tools exist that can provide information about material evolution during battery usage.Voltage is a common tool for characterizing battery materials during operation, particularly the derivative of voltage with respect to state of charge, dV/dQ. A cell's voltage is directly related to the chemistry of the materials, and many previous studies have investigated battery voltage and used it to identify phase transitions in materials, predict the effects of cell aging, and relate voltage to underlying chemical reactions. [2][3][4][5][6] In addition, many of these studies have resulted in the development of models to help understand battery material evolution by predicting voltage curves based on the fundamental physics in the battery. dV/dQ has proven to be an extremely useful tool and an accurate predictor of cell aging, but it is limited by physical constraints. Notably, electrode phase transitions are most easily viewed at slow charge rates, and the distinguishing features in a dV/dQ plot are nonexistent at high charge rates. Studies often cycle batteries at charge rates of C/20 or lower in order to glean information from dV/dQ curves.Recent battery research has focused on mechanical properties, such as strain, ε, as a novel tool to indicate underlying phenomena. 5,[7][8][9][10][11][12] This previous research relies on the fact that during battery operation, electrode materials are known to expand and contract in repeatable patterns. S...

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“…While some have suggested the transport of Li + ions in the electrolyte is an important factor [19], there is growing consensus that the slow solid state diffusion of Li + ions into graphites, at high rates, is the major factor [20,21], although the precise mechanism(s) is still the subject of continuing research.…”

Section: Resultsmentioning

confidence: 99%

“…Upon initial charging of a graphite electrode, there is often an initial expansion of the graphite interlayer distance due to the co-intercalation of solvent, prior to the formation of a solid electrolyte interface (SEI) passivating layer [21]. The formation of the porous SEI layer stabilizes the graphite surface and subsequently only allows unsolvated Li + ions to pass through and diffuse into the graphite lattice [22].…”

Section: Resultsmentioning

confidence: 99%

Rate capability of graphite materials as negative electrodes in lithium-ion capacitors

Sivakkumar

Nerkar

Pandolfo

2010

Electrochimica Acta

287

172

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A Dilatometric Study of Lithium Intercalation into Powder-Type Graphite Electrodes

Cited by 103 publications

References 18 publications

Polymer microsphere embedded Si/graphite composite anode material for lithium rechargeable battery

Polymer microsphere embedded Si/graphite composite anode material for lithium rechargeable battery

Strain Derivatives for Practical Charge Rate Characterization of Lithium Ion Electrodes

Rate capability of graphite materials as negative electrodes in lithium-ion capacitors

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