Thermodynamics of Electrode Materials for Lithium‐Ion Batteries

Yazami, Rachid

doi:10.1002/9783527629022.ch5

Cited by 22 publications

(32 citation statements)

References 100 publications

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“…It is seen from Figure 15 that the Li composition in LiCoO2 does not get reduced when the bias voltage is ~1.3 V. Hereafter, it decreases as the bias voltage increases. The characteristic relation obtained from the Li depth profiling by means of the ERD technique corresponds well with the one measured by the electrochemical method [19]. The threshold voltage (~1.3V) for the depletion of Li from LiCoO2 under conditions of charging is ascribed to the enrichment of Li at the interface with the Au electrode.…”

Section: Au/lco/latp/pt Batterysupporting

confidence: 75%

Dynamic Behavior of Li in Solid-State Li-Ion Batteries Studied using MeV Ion Beam Analysis Techniques

Morita¹,

Tsuchiya²

2021

JEPT

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In this review, various studies on the Li depth profiles of metal/electrolyte/metal capacitors and batteries of Au/LCO/LATP/Pt, LCO/LiPON/Si, and LMO/LiPON/NbO with different metal electrodes at both sides (by bias; LCO =LiCoO2, LATP =Li3.1Al0.86Ti1.14Ge1.27P1.73O12, LMO =LiMn2O4, NbO = Nb2O5) using the in-situ reflection ERD (ERD) technique with 9MeV O+4 ion beam and transmission ERD (TERD) technique with 5MeV He+2 ion beam, respectively, are described. For capacitors, the transport fraction of Li-ion in the electrolyte is less than unity. The Li atoms diffuse in the direction opposite to the ion. It has been shown that the batteries are rechargeable. On the other hand, it is observed that an anomalous over-charging takes place when the batteries are over-biased (Si/LiPON/LCO and LMO/LiPON/NbO), and strong reactions of Li with the metal electrodes take place under these conditions. The anomaly observed is explained in terms of the imbalance in the capacities of Li in anode and cathode, which can be attributed to the sizeable amounts of hydrogen present as an impurity during the fabrication of the battery. This is because hydrogen can potentially reduce the capacity of Li in both anode and cathode. The reactions of Li with metal electrodes are discussed in terms of the transport fraction of Li ions (less than unity) and the difference in the work functions of metal electrodes at both sides. Finally, it is noted that the removal of hydrogen in batteries can potentially improve safety, efficiency, and lifetime. These can be achieved by reducing the reaction of Li with metal electrodes. The recoil-scatter method in the TERD technique can measure the Li depth profile in the absence of background yields.

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Section: Au/lco/latp/pt Batterysupporting

confidence: 75%

Dynamic Behavior of Li in Solid-State Li-Ion Batteries Studied using MeV Ion Beam Analysis Techniques

Morita¹,

Tsuchiya²

2021

JEPT

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“…3,4 However, there is only a little prior work using this method for investigating lithium intercalation into carboneous materials, [5][6][7][8][9] or other graphite intercalation compounds. 10 Takano et al 11 studied full Li-ion batteries, which made it difficult to discuss the results.…”

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confidence: 99%

Thermodynamics of Lithium Intercalation into Graphites and Disordered Carbons

Reynier¹,

Yazami²,

Fultz³

2004

J. Electrochem. Soc.

148

125

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The temperature dependence of the open-circuit potential of lithium half-cells was measured for electrodes of carbon materials having different amounts of structural disorder. The entropy of lithium intercalation, ⌬S, and enthalpy of intercalation, ⌬H, were determined over a broad range of lithium concentrations. For the disordered carbons, ⌬S is small. For graphite, an initially large ⌬S decreases with lithium concentration, becomes negative, and then shows two plateaus associated with the formation of intercalation compounds. For all carbons ⌬H is negative, and decreases in magnitude with increased lithium concentration. For lithium concentrations less than x ϭ 0.5 in Li x C 6 , for the disordered carbons the magnitude of ⌬H is significantly more negative than for graphite ͑i.e., intercalation is more exothermic͒. The temperature dependence of the open-circuit voltage ͑OCV͒, in equilibrated half-cells can be used to determine the entropy, ⌬S, and enthalpy, ⌬H, of the lithium intercalation reactionFor an electrochemical system, the Gibbs free energy, ⌬G, can be related to the OCV, E 0 . 2,3 In this study ⌬G is defined as the OCV measured after at least 3 h restwhere F is the Faraday constant and T the absolute temperature. The entropy of formation isand enthalpy of formation is obtained from Eq. 2 and 3 asIn what follows, the variation of any state function, ⌬G, ⌬H, and ⌬S, relates to adding an incremental amount of lithium into the host material having lithium concentration x, taking metallic bcc lithium and the pure carboneous material as reference.The OCV method has been used to study some intercalation compounds, such as Li x TiS2 or manganese oxides.3,4 However, there is only a little prior work using this method for investigating lithium intercalation into carboneous materials, 5-9 or other graphite intercalation compounds.10 Takano et al. 11 studied full Li-ion batteries, which made it difficult to discuss the results. These previous investigations did not address the effect of disorder in the carbon materials, or the mechanisms of lithium intercalation. Here we report results of a temperature-dependent OCV study on how the degree of graphitization in carbon materials altered their dependence on ⌬S and ⌬H on lithium concentration. The effects of structural disorder on both entropy and enthalpy were large, and can be explained only in part by the configurational entropy of mixing. ExperimentalMesocarbon microbeads ͑MCMB͒ were provided by Osaka Gas, Japan, with different heat-treatment temperatures of 750, 1000, and 2800°C. Natural graphite from Superior Graphite, Chicago, IL, was also used for the electrochemical measurements ͑Ref. SO 3-24-1͒. The MCMB material heat-treated at 750°C was prepared from the so-called green powder by heating under nitrogen flow in a standard tube furnace. The temperature ramp was set to 10°C per hour to prevent sintering, and the final temperature was maintained for 2 h. The two other MCMB materials were heat-treated by Osaka Gas at 1000 and 2800°C.Coin cells of 20 mm diam an...

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“…Presently most practical lithium-ion batteries use synthetic performed by us in 1992 using SEM [4,5]. The inorganic/ organic/polymer nature of the SEI was then discerned by FTIR [6], and its composition [7] and its multilayer structure were later characterized [7][8].…”

Section: Introductionmentioning

confidence: 99%

Interfacial phenomena on the graphite-lithium electrode during the formation process and thermal aging

Yazami

Martinent²,

Reynier³

2002

Ionics

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International audienceSlow scan voltammery (SSV), electrochemical impedance spectroscopy (EIS) and galvanostatic cycling (GC) were used to characterize the formation of the Solid Electrolyte Interphase (SEI) on a graphite electrode during lithiation and delithiation and during thermal aging. The SSV and GC results show the irreversible character of the first reduction peak/semi-plateau at 0.8 V. After aging, a new irreversible plateau appears in the GC curves. Concomitantly the interfacial resistances as determined from the Nyquist plots increased then decreased as the signature of SEI transformation. We suggest the SEI is subjected to precipitation/dissolution processes

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Thermodynamics of Electrode Materials for Lithium‐Ion Batteries

Cited by 22 publications

References 100 publications

Dynamic Behavior of Li in Solid-State Li-Ion Batteries Studied using MeV Ion Beam Analysis Techniques

Dynamic Behavior of Li in Solid-State Li-Ion Batteries Studied using MeV Ion Beam Analysis Techniques

Thermodynamics of Lithium Intercalation into Graphites and Disordered Carbons

Interfacial phenomena on the graphite-lithium electrode during the formation process and thermal aging

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