A method of increasing the energy density of layered Ni-rich Li[Ni 1-2: X Co x Mn x ]O 2 cathodes (x = 0.05, 0.1, 0.2)

Jae Hyung Kim, Kang Joon Park, Suk Jun Kim, Chong S. Yoon, Yang-Kook Sun

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Lithium-ion batteries with high energy density, long cycle life, and appropriate safety levels are necessary to facilitate the penetration of electrified transportation systems into the automobile market. Currently, Ni-rich layered Li[Ni 1-2x Co x Mn x ]O 2 (NCM, x ≤ 0.2) cathodes show high capability for increasing the energy densities of cells. However, the poor thermal stability of this type of cathode is retarding their commercialization. In this study, it is demonstrated that operating Ni-rich cathodes at higher cut-off potentials (>4.3 V) rather than progressing to highly nickel enriched compositions can be a better method of enhancing their energy densities and maintaining adequate thermal stability. It is shown that a Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (NCM-622) cathode cycled up to 4.5 V exhibits a discharge capacity of 200 mA h g -1 and a capacity retention of 93% after 100 cycles, which are similar to those of Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM-811) cycled up to 4.3 V. A similar volume change during cycling and comparable NiO-like rocksalt impurity layer after 100 cycles in both of the cathodes may be the reason for their similar cycle lives despite operating at different charge cut-off potentials. In spite of the comparable capacity and retention, the NCM-622 cathode exhibits superior thermal stability, in which the occurrence of the exothermic reaction is delayed by 50 °C, to NCM-811. In addition, analogous trends are observed in the cathodes with higher nickel compositions, i.e., NCM-811 and Li[Ni 0.9 Co 0.05 Mn 0.05 ]O 2 cycled up to 4.5 V and 4.3 V, respectively.

Original languageEnglish
Pages (from-to)2694-2701
Number of pages8
JournalJournal of Materials Chemistry A
Volume7
Issue number6
DOIs
StatePublished - 2019 Jan 1

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Cathodes
Thermodynamic stability
Nickel
Life cycle
Exothermic reactions
Chemical analysis
Automobiles
Impurities

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@article{b3a44a9571924db7802ddff756be6629,
title = "A method of increasing the energy density of layered Ni-rich Li[Ni 1-2: X Co x Mn x ]O 2 cathodes (x = 0.05, 0.1, 0.2)",
abstract = "Lithium-ion batteries with high energy density, long cycle life, and appropriate safety levels are necessary to facilitate the penetration of electrified transportation systems into the automobile market. Currently, Ni-rich layered Li[Ni 1-2x Co x Mn x ]O 2 (NCM, x ≤ 0.2) cathodes show high capability for increasing the energy densities of cells. However, the poor thermal stability of this type of cathode is retarding their commercialization. In this study, it is demonstrated that operating Ni-rich cathodes at higher cut-off potentials (>4.3 V) rather than progressing to highly nickel enriched compositions can be a better method of enhancing their energy densities and maintaining adequate thermal stability. It is shown that a Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (NCM-622) cathode cycled up to 4.5 V exhibits a discharge capacity of 200 mA h g -1 and a capacity retention of 93{\%} after 100 cycles, which are similar to those of Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM-811) cycled up to 4.3 V. A similar volume change during cycling and comparable NiO-like rocksalt impurity layer after 100 cycles in both of the cathodes may be the reason for their similar cycle lives despite operating at different charge cut-off potentials. In spite of the comparable capacity and retention, the NCM-622 cathode exhibits superior thermal stability, in which the occurrence of the exothermic reaction is delayed by 50 °C, to NCM-811. In addition, analogous trends are observed in the cathodes with higher nickel compositions, i.e., NCM-811 and Li[Ni 0.9 Co 0.05 Mn 0.05 ]O 2 cycled up to 4.5 V and 4.3 V, respectively.",
author = "Kim, {Jae Hyung} and Park, {Kang Joon} and Kim, {Suk Jun} and Yoon, {Chong S.} and Yang-Kook Sun",
year = "2019",
month = "1",
day = "1",
doi = "10.1039/c8ta10438g",
language = "English",
volume = "7",
pages = "2694--2701",
journal = "Journal of Materials Chemistry A",
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A method of increasing the energy density of layered Ni-rich Li[Ni 1-2: X Co x Mn x ]O 2 cathodes (x = 0.05, 0.1, 0.2) . / Kim, Jae Hyung; Park, Kang Joon; Kim, Suk Jun; Yoon, Chong S.; Sun, Yang-Kook.

In: Journal of Materials Chemistry A, Vol. 7, No. 6, 01.01.2019, p. 2694-2701.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - A method of increasing the energy density of layered Ni-rich Li[Ni 1-2: X Co x Mn x ]O 2 cathodes (x = 0.05, 0.1, 0.2)

AU - Kim, Jae Hyung

AU - Park, Kang Joon

AU - Kim, Suk Jun

AU - Yoon, Chong S.

AU - Sun, Yang-Kook

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Lithium-ion batteries with high energy density, long cycle life, and appropriate safety levels are necessary to facilitate the penetration of electrified transportation systems into the automobile market. Currently, Ni-rich layered Li[Ni 1-2x Co x Mn x ]O 2 (NCM, x ≤ 0.2) cathodes show high capability for increasing the energy densities of cells. However, the poor thermal stability of this type of cathode is retarding their commercialization. In this study, it is demonstrated that operating Ni-rich cathodes at higher cut-off potentials (>4.3 V) rather than progressing to highly nickel enriched compositions can be a better method of enhancing their energy densities and maintaining adequate thermal stability. It is shown that a Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (NCM-622) cathode cycled up to 4.5 V exhibits a discharge capacity of 200 mA h g -1 and a capacity retention of 93% after 100 cycles, which are similar to those of Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM-811) cycled up to 4.3 V. A similar volume change during cycling and comparable NiO-like rocksalt impurity layer after 100 cycles in both of the cathodes may be the reason for their similar cycle lives despite operating at different charge cut-off potentials. In spite of the comparable capacity and retention, the NCM-622 cathode exhibits superior thermal stability, in which the occurrence of the exothermic reaction is delayed by 50 °C, to NCM-811. In addition, analogous trends are observed in the cathodes with higher nickel compositions, i.e., NCM-811 and Li[Ni 0.9 Co 0.05 Mn 0.05 ]O 2 cycled up to 4.5 V and 4.3 V, respectively.

AB - Lithium-ion batteries with high energy density, long cycle life, and appropriate safety levels are necessary to facilitate the penetration of electrified transportation systems into the automobile market. Currently, Ni-rich layered Li[Ni 1-2x Co x Mn x ]O 2 (NCM, x ≤ 0.2) cathodes show high capability for increasing the energy densities of cells. However, the poor thermal stability of this type of cathode is retarding their commercialization. In this study, it is demonstrated that operating Ni-rich cathodes at higher cut-off potentials (>4.3 V) rather than progressing to highly nickel enriched compositions can be a better method of enhancing their energy densities and maintaining adequate thermal stability. It is shown that a Li[Ni 0.6 Co 0.2 Mn 0.2 ]O 2 (NCM-622) cathode cycled up to 4.5 V exhibits a discharge capacity of 200 mA h g -1 and a capacity retention of 93% after 100 cycles, which are similar to those of Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM-811) cycled up to 4.3 V. A similar volume change during cycling and comparable NiO-like rocksalt impurity layer after 100 cycles in both of the cathodes may be the reason for their similar cycle lives despite operating at different charge cut-off potentials. In spite of the comparable capacity and retention, the NCM-622 cathode exhibits superior thermal stability, in which the occurrence of the exothermic reaction is delayed by 50 °C, to NCM-811. In addition, analogous trends are observed in the cathodes with higher nickel compositions, i.e., NCM-811 and Li[Ni 0.9 Co 0.05 Mn 0.05 ]O 2 cycled up to 4.5 V and 4.3 V, respectively.

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