Underlying limitations behind impedance rise and capacity fade of single crystalline Ni-rich cathodes synthesized via a molten-salt route

Azhari, Luqman; Meng, Zifei; Yang, Zhenzhen; Gao, Guanhui; Han, Yimo; Wang, Yan

doi:10.1016/j.jpowsour.2022.231963

Cited by 15 publications

(13 citation statements)

References 62 publications

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“…6 The molten-salt synthesis (MSS) process has been also considered as a cost-effective method due to its low thermal energy consumption in producing homogeneous (both chemical composition and size) cathode materials for LIBs. [7][8][9][10] Nevertheless, the removal of salt after formation of the final product is crucial and several times of washing with water are needed to separate cathode material from the used salt, resulting in higher water consumption. 11 Moreover, hydroxide precursors are typically used in the MSS process which adds an additional step to make single crystal NMC cathode materials.…”

mentioning

confidence: 99%

Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Tahmasebi

Zheng²,

Hatchard³

et al. 2023

J. Electrochem. Soc.

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Layered lithium nickel manganese cobalt oxide or NMC type cathode materials dominate the lithium-ion battery market. However, the production of their precursor involves the use of large amounts of water and can create waste. All-dry synthesis methods are attractive as they are potentially cheaper and greener. However, it remains a challenge to achieve atomic scale mixing of the precursor elements by dry methods. Here, we report an alternate route to achieve atomic scale mixing by employing thermal interdiffusion to produce a phase pure rock salt structure precursor for NMC cathode materials, which can significantly shorten the preparation time and may further reduce cost. The complications and applicability of using a thermally synthesized precursor to make layered cathode material are presented in detail.

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confidence: 99%

Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Tahmasebi

Zheng²,

Hatchard³

et al. 2023

J. Electrochem. Soc.

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“…[ 9 ] The molten salt‐assisted synthesis involves a solid‐liquid reaction that proceeds at mild temperature and reduced dwell time. This synthetic methodology has been widely used for SC Ni‐rich cathode materials [ 25–27 ] but remains to be investigated for the preparation of SC, submicron‐scale, and nonstoichiometric Li 1+ x Ni 1‐ x O 2 .…”

Section: Introductionmentioning

confidence: 99%

“…[9] The molten salt-assisted synthesis involves a solid-liquid reaction that proceeds at mild temperature and reduced dwell time. This synthetic methodology has been widely used for SC Ni-rich cathode materials [25][26][27] but remains to be investigated for the preparation of SC, submicron-scale, and nonstoichiometric Li Here, we report a molten salt-assisted preparation of SC, submicron-sized (average 300 nm) and slightly Li-rich Li 1.045 Ni 0.955 O 2 (LR-LNO). In addition, a Li-refeeding approach was applied to promote the surface phase transition from rock-salt to layered phase during synthesis.…”

Section: Introductionmentioning

confidence: 99%

Molten Salt‐Assisted Synthesis of Single‐Crystalline Nonstoichiometric Li₁₊_xNi_1–_xO₂ with Improved Structural Stability

Ding

Yao

et al. 2023

Advanced Energy Materials

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Cobalt-free LiNiO 2 is an attractive cathode material with high energy density and low cost but suffers from severe structural degradation and poor performance. Here, a molten salt-assisted synthesis combined with a Li-refeeding strategy is proposed to obtain nonstoichiometric Li 1+x Ni 1-x O 2 with submicron particle size and superior rate performance. The slightly Li-rich and single-crystalline characters inhibit Li + /Ni 2+ anti-site defects and mitigates the undesirable phase evolution. Remarkably, single-crystalline Li 1.045 Ni 0.955 O 2 exhibits a high specific capacity (218.7 mAh g −1 at 0.1 C), considerable rate capability (187.0 mAh g −1 at 5 C), and an initial Coulombic efficiency (89.62% at 0.1 C) in the 1.27 Ah pouch full cell employing the graphite anode, significantly outperforming near stoichiometric LiNiO 2 . Furthermore, the particulate morphology of Li 1.045 Ni 0.955 O 2 remains intact at charge voltages up to 4.8 V, whereas near stoichiometric LiNiO 2 features intragranular cracks and irreversible lattice distortion. This study underscores the value of molten salt-assisted synthesis and Li-refeeding modification to upgrade Ni-based layered oxide cathode materials for advanced Li-ion batteries.

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“…This synthesis technique typically utilizes hydroxide precursors (HPs), and the molten salt is used to enhance crystal growth at lower temperatures. In fact, molten salt techniques require additional steps including washing the products with water which leads to a higher water consumption. − Accordingly, all-dry NMC synthesis techniques have drawn interest recently in order to reduce cathode synthesis cost and reduce waste substantially. ,,− …”

Section: Introductionmentioning

confidence: 99%

New Insights into the All-Dry Synthesis of NMC622 Cathodes Using a Single-Phase Rock Salt Oxide Precursor

Tahmasebi,

Obrovac

2023

ACS Omega

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In this study, new insights into the all-dry synthesis of the LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) cathode using a singlephase rock-salt (RS) oxide precursor are provided. It was found that use of a larger amount of excess Li content not only can enhance the electrochemical performance of NMC made from the RS-precursor but also increase the degree of homogeneity of the NMC cathode material. In situ XRD analysis showed that lithiation of the RS-precursor (i.e., formation of the O3-phase) starts at a higher synthesis temperature (∼450 °C) than that is required when using a hydroxide precursor (HP) and lithium carbonate (∼350 °C). Consequently, Li 2 CO 3 was consumed by the reaction with the HP at low temperatures before the temperature reached the Li 2 CO 3 melting point. In contrast, the reduced lithiation kinetics of the RS-precursor results in the presence of liquid Li 2 CO 3 during the synthesis, which rapidly increases the rates of precursor lithiation and increases the NMC primary particle size.

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Underlying limitations behind impedance rise and capacity fade of single crystalline Ni-rich cathodes synthesized via a molten-salt route

Cited by 15 publications

References 62 publications

Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Molten Salt‐Assisted Synthesis of Single‐Crystalline Nonstoichiometric Li₁₊_xNi_1–_xO₂ with Improved Structural Stability

New Insights into the All-Dry Synthesis of NMC622 Cathodes Using a Single-Phase Rock Salt Oxide Precursor

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Underlying limitations behind impedance rise and capacity fade of single crystalline Ni-rich cathodes synthesized via a molten-salt route

Cited by 15 publications

References 62 publications

Li[Ni0.6Mn0.2Co0.2]O2 Made From Crystalline Rock Salt Oxide Precursors

Li[Ni0.6Mn0.2Co0.2]O2 Made From Crystalline Rock Salt Oxide Precursors

Molten Salt‐Assisted Synthesis of Single‐Crystalline Nonstoichiometric Li1+xNi1–xO2 with Improved Structural Stability

New Insights into the All-Dry Synthesis of NMC622 Cathodes Using a Single-Phase Rock Salt Oxide Precursor

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Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Li[Ni_0.6Mn_0.2Co_0.2]O₂ Made From Crystalline Rock Salt Oxide Precursors

Molten Salt‐Assisted Synthesis of Single‐Crystalline Nonstoichiometric Li₁₊_xNi_1–_xO₂ with Improved Structural Stability