Changes of Degradation Mechanisms of LiFePO4/Graphite Batteries Cycled at Different Ambient Temperatures

Shu, Sun; Guan, Ting; Shen, Bin; Leng, Kunyue; Gao, Yunzhi; Cheng, Xinqun; Yin, Geping

doi:10.1016/j.electacta.2017.03.158

Cited by 58 publications

(39 citation statements)

References 46 publications

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“…Figure shows the periodically measured capacity loss of LiFePO 4 /graphite full cells under six different rates (1/3C, 1.0C, 1.5C, 1.8C, 2.0C and 2.5C) with cycling days. A slight undulation in the curves of capacity loss is owing to the mild temperature instability.…”

Section: Resultsmentioning

confidence: 99%

Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

et al. 2018

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In this study, different charge/discharge rates (1/3C, 1C, 1.5C, 1.8C, 2.0C and 2.5C) are used to accelerate the aging of commercial LiFePO4/graphite cells. The capacity attenuation mechanism is investigated by disassembling the aged full cells and analyzing the morphologies and chemical composition of electrode surfaces, the single electrode potentials, and so forth, when the capacity retention of full cell decays to 95 %, 90 %, 85 %, and 80 %. Through the tests, the capacity fade of the full cell is mainly ascribed to the irreversible loss of active lithium. However, when the test rate is not lower than 2.0C, the dominant mechanism for consumption of active lithium is changed to lithium deposition on the anode during the charging process instead of the generation of SEI film. As a consequence, the capacity decay rate at 2.0C or 2.5C is accelerated to a large degree. The capacity loss with cycling time is fitted by Arrhenius equations. The pre‐exponential factor at a given rate (Arate) increases linearly with the rising test rate when it is not more than 1.8C, and this corresponds to the results of disassembly analysis. Therefore, an unknown Arate in a reasonable range can be extrapolated by the data of other Arate values at relatively high rates. In addition, the calculated Arate after 10 % capacity loss can be used to replace the fitted value by the whole aging data. This provides a rapid and practical approach to estimate the lifetime of the full cell.

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Section: Resultsmentioning

confidence: 99%

Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

et al. 2018

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“…7a, the intensity of peaks for the FePO 4 phase is increased aer aging, which is indicated that some lithium ions cannot come back to the cathode when the full cell is discharged to 2.5 V. Generally, this part of active lithium is consumed irreversibly in the anode due to the formation of SEI lm or other side reactions. 16,29 In addition, the peaks of (200), (020) and (002) shi to low angle direction when the full cells decay to the end of life, especially for the high discharge rates (Fig. 7b).…”

Section: The Structures Analysismentioning

confidence: 95%

“…The capacity fade of lithium ion batteries is strongly related to the use conditions, such as the charge and discharge rate, [16][17][18][19] the cut-off voltage, [19][20][21] the depth of discharge (DOD), [22][23][24] the state of charge (SOC) [25][26][27] and the ambient temperature, [28][29][30][31][32][33][34] which all have inuences on the performance and the lifetime of lithium ion batteries. In general, the primary cause of capacity fade is attributed to the loss of active lithium which might result from the generation of solid electrolyte interface (SEI) lm on the anode, the deposition of lithium or electrolyte decomposition.…”

Section: 15mentioning

confidence: 99%

“…However, when the discharge rate is higher than 3.0C, the accelerating effect on the capacity fade is not evident, as well as the change of discharging time. Generally, if the capacity loss of LiFePO 4 /graphite full cell is mainly caused by the consumption of active lithium owing to the generation and development of SEI lm on the anode, the square root of lifetime has a negative correlation with the discharge rates, 29,38 and the relationship is shown in Fig. 1d.…”

Section: Analysis Aer Disassemblymentioning

confidence: 99%

“…29,[40][41][42] The high content of oxygen containing compounds indicates that there are more decomposition products of electrolyte deposited on the anode surface during aging at 0.5C. This is because that the SEI lm is mainly generated during the charging process and its thickness has a positive correlation with the number of cycles.…”

Section: 40-42mentioning

confidence: 99%

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Accelerated aging and degradation mechanism of LiFePO₄/graphite batteries cycled at high discharge rates

et al. 2018

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The effects of discharge rates (0.5C, 1.0C, 2.0C, 3.0C, 4.0C and 5.0C) on the aging of LiFePO 4 /graphite full cells are researched by disassembling the fresh and aged full cells. The capacity degradation mechanism is analyzed via electrochemical performance, surface morphologies and compositions, and the structure of the anode and cathode electrodes. The capacity fade is accelerated with increasing discharge rates. The irreversible loss of active lithium due to the generation of an SEI film is the primary aging factor for the full cells cycled at low discharge rates. However, when the discharge rate is greater than or equal to 4.0C, the performance degradation of the LiFePO 4 electrode is distinct due to structure decay, which is caused by quick and repeated intercalation of lithium ions and elevated temperature during discharging.In addition, the SEI film on the anode tends to be unstable after the rapid extraction of lithium ions at high discharge rates, and this enhances the loss of active lithium. Therefore, it is indicated that the degradation mechanism is changed for the full cells aged at 4.0C and 5.0C. Besides, the high discharge rate also increases the internal resistance of the full cell, which is detrimental to high rate discharge performance.

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Quantitative Analysis of Active Lithium Loss and Degradation Mechanism in Temperature Accelerated Aging Process of Lithium‐Ion Batteries

Peng,

Zhong,

Ding

et al. 2024

Adv Funct Materials

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Quantifying the aging mechanisms and their evolution patterns during battery aging is crucial for enabling renewable energy. Here, key factors are monitored and quantified affecting the aging processes of LiFePO4//graphite battery by a combination of mass spectrometry titration (MST), nuclear magnetic resonance (NMR), cryogenic transmission electron microscopy (cryo‐TEM), and neutron imaging techniques. Electrochemical analysis reveals the loss of active lithium inventory drives battery aging as temperature increases. It is shown that temperature‐induced accelerated decaying rate is 2.01 and 3.45 times at 45 and 65 °C compared with that of rate at 25 °C. Quantitative analysis indicates that irreversible formation of LixC6 (x ≤ 1), LiF, ROCO2Li, LiH, Li2C2, and RLi (R = CH3, C2H3, C2H5, C3H5) are the primary components of inactive lithium. The solid eletrolyte interpahse (SEI), excluding LixC6, constitutes over 70% of the total inactive lithium. With increasing cycles, SEI shows a decreasing proportion of LiF and an increasing proportion of ROCO2Li. The coupled effects of substantial SEI growth, increased irreversible formation of LixC6, and worsened conductivity result in the rapid aging of batteries tested at high temperatures. In this work, a research toolbox for the quantitative study of aging mechanisms in practical batterysystems has been provided.

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Changes of Degradation Mechanisms of LiFePO4/Graphite Batteries Cycled at Different Ambient Temperatures

Cited by 58 publications

References 46 publications

Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

Accelerated aging and degradation mechanism of LiFePO₄/graphite batteries cycled at high discharge rates

Quantitative Analysis of Active Lithium Loss and Degradation Mechanism in Temperature Accelerated Aging Process of Lithium‐Ion Batteries

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Changes of Degradation Mechanisms of LiFePO4/Graphite Batteries Cycled at Different Ambient Temperatures

Cited by 58 publications

References 46 publications

Accelerated Aging Analysis on Cycle Life of LiFePO4/Graphite Batteries Based on Different Rates

Accelerated Aging Analysis on Cycle Life of LiFePO4/Graphite Batteries Based on Different Rates

Accelerated aging and degradation mechanism of LiFePO4/graphite batteries cycled at high discharge rates

Quantitative Analysis of Active Lithium Loss and Degradation Mechanism in Temperature Accelerated Aging Process of Lithium‐Ion Batteries

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Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

Accelerated Aging Analysis on Cycle Life of LiFePO₄/Graphite Batteries Based on Different Rates

Accelerated aging and degradation mechanism of LiFePO₄/graphite batteries cycled at high discharge rates