The effect of lithium-excess on Ni-rich LiNi0.6Co0.2Mn0.2O2 cathode materials prepared by a Taylor flow reactor

Truong, Thi BeTa; Wu, Yi‐Shiuan; Hung, Tai‐Feng; Chien, Wen-Chen; Huang, Wei‐Hsiang; Jose, Rajan; Lue, Shingjiang Jessie; Yang, Chun–Chen

doi:10.1016/j.electacta.2021.138982

Cited by 13 publications

(5 citation statements)

References 62 publications

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“…Recent studies have found that a high Li excess in Li 1+ x (NiCoMn) 1– x O 2 (Ni < 0.88) systems can improve the structural stability of the layered cathode materials. − Nevertheless, in a Ni-rich cathode, the use of a high amount of Li sources may lead to Li impurities on the surfaces of the particles as a result of reactions with moisture in the air . Such excessive Li residues in Ni-rich cathodes can have several undesirable effects: (i) a highly alkaline (pH > 11) surface that can initiate defluorination of the polyvinylidene fluoride (PVDF) binder; this behavior can lead to particle agglomeration and a slurry that undergoes a rapid increase in viscosity, eventually undergoing gelation during cathode fabrication and deteriorating the mechanical properties of the cathode; , (ii) slow Li + -ion diffusion and charge transfer at the interface and accelerated formation of HF; (iii) gas evolution and cell swelling, as a result of the decomposition of carbonate species in the Li residue through the HF attack; , (iv) LiOH reacts with CO 2 and CO to form a Li 2 CO 3 layer on the surface; this process accelerates the decomposition of the electrolytic salt (LiPF 6 ) and leads to the formation of an insulating surface layer of LiF that resists the diffusion of Li + ions; (v) oxidative decomposition of LiOH and Li 2 CO 3 at high voltages, causing an irreversible capacity; and (vi) capacity fading, due to dissolution of the TMs on the particle surface .…”

Section: Introductionmentioning

confidence: 99%

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

Abebe

Yang

et al. 2021

ACS Appl. Energy Mater.

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Nickel-rich layered oxide cathode materials having a Ni content of ≥90% have great potential for use in next-generation lithium-ion batteries (LIBs) due to their high energy densities and relatively low cost. They suffer, however, from poor cycling performance and rate capability, significantly hampering their widespread applicability. In this study, we synthesized a Ni-rich precursor through a co-precipitation method and added different amounts of the Li excess on the precursors using a solid-state method to obtain sintered Li1+x (Ni0.9Co0.05Mn0.05)1–x O2 (denoted as L1+x -NCM; x = 0.00, 0.02, 0.04, 0.06, and 0.08) transition metal (TM) oxide cathode materials. The L1+x -NCM cathode having a Li excess of 4% exhibited a discharge capacity of ca. 216.17 mA h g–1 at 2.7–4.3 V, 0.1 C and retained 95.7% of its initial discharge capacity (ca. 181.39 mA h g–1) after 100 cycles of 1 C charge/discharge which is the best performance as compared with stoichiometric Li1+x (Ni0.9Co0.05Mn0.05)1–x O2 (i.e., x = 0, Li/TM = 1:1). Furthermore, a high-rate capability of ca. 162.92 mA h g–1 at a rate of 10 C led to the 4% Li excess, optimizing the electrochemical performance, relative to the other Li-excess samples. Ex/in situ X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy revealed that the 4% Li excess in the Ni-rich NCM90 cathode material (i) decreased the Li+/Ni2+ disorder by increasing the content of Ni3+ in the TM slab, (ii) increased the crystallinity, and (iii) accelerated Li+-ion transport by widening the Li slab. Furthermore, electrochemical impedance spectroscopy and cyclic voltammetry confirmed that the appropriate Li excess lowered the electrochemical impedance and improved the reversibility of the electrochemical reaction. Therefore, our results revealed that NCM90 cathode materials featuring an optimal Li excess are potential candidates for use in next-generation LIBs.

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Section: Introductionmentioning

confidence: 99%

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

Abebe

Yang

et al. 2021

ACS Appl. Energy Mater.

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“…The calculation of d (Li–O) reveals that S-NMA (2.5314 Å) exceeds P-NMA (2.4255 Å) by 0.1059 Å. This suggests that Li + benefits from a broader transport channel, facilitating its migration . Remarkably, the calculation of Ni 2+ occupancy at the Li site indicates that the Li + /Ni 2+ mixing rate is 3.594% in S-NMA, compared to 5.928% in P-NMA.…”

Section: Resultsmentioning

confidence: 87%

“…This suggests that Li + benefits from a broader transport channel, facilitating its migration. 33 Remarkably, the calculation of Ni 2+ occupancy at the Li site indicates that the Li + /Ni 2+ mixing rate is 3.594% in S-NMA, compared to 5.928% in P-NMA. This difference arises because polycrystals consist of closely packed nanosized particles with different crystal faces in proximity.…”

Section: Figures 2i and S1mentioning

confidence: 99%

PVP-Assisted Hydrothermal Synthesis of Nickel-Rich Cobalt-Free Single-Crystal LiNi_0.9Mn_0.05Al_0.05O₂ for Lithium-Ion Batteries

He,

Liu,

Liu

et al. 2024

ACS Appl. Energy Mater.

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Given cobalt's scarcity and high toxicity, there is a considerable interest in nickel-rich materials with reduced or no cobalt content. However, the majority of such materials are polycrystalline particles, which are susceptible to mechanical breakage and structural deterioration during cycling, resulting in rapid capacity decay. Here, we synthesized dispersed and uniform precursors using a poly(vinylpyrrolidone) (PVP)-assisted hydrothermal approach, followed by calcination to produce nickel-rich, cobalt-free single-crystal LiNi 0.9 Mn 0.05 Al 0.05 O 2 (NMA) cathode materials. The single-crystal morphology effectively reduced intergranular cracking in the cathode material, preserving phase transition reversibility and cycle stability. At a current density of 0.5C, S-NMA exhibited a maximum discharge-specific capacity of 179.2 mAh g −1 with a capacity retention of 93.45% after 100 cycles. Additionally, at 55 °C and a current density of 1C, it reached 213.6 mAh g −1 with a capacity retention of 93.3% after 50 cycles. The single-crystal morphology of the cathode material exhibited an outstanding electrochemical performance. This study offers a novel approach to synthesizing nickel-rich single-crystal precursors for cathodes, which holds considerable promise for the advancement of high-performance cathode materials.

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“…2b). In the common practice of synthesizing Ni-based CAMs, excess Li source (e.g., LiOH) is added to the precursors to compensate for Li loss during high-temperature calcination and to ensure the formation of Li-stoichiometric layer-structured CAMs in the final product [30][31][32] . The Li/Ni mixing issue cannot be eliminated in Co-free CAMs, even under optimized calcination (e.g., through tuning temperature, and time) 33 .…”

Section: Mainmentioning

confidence: 99%

“…Further process analysis, using in situ synchrotron X-ray diffraction correlated with multiscale modeling, reveals the predominant role of Li stoichiometry in driving structural ordering and crystal growth during calcination. Specifically, liquid-phase sintering occurs when there is excess Li, leading to the large primary particles commonly reported in the literature 30,31 .…”

Section: Mainmentioning

confidence: 99%

Stabilizing Cobalt-Free Cathodes with Lithium-Stoichiometry Control for Sustainable Lithium-ion Batteries

Chen

Barai

Kahvecioğlu

et al. 2023

Preprint

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Lithium-ion batteries are essential to decarbonizing transportation and power grids, but their reliance on high-cost earth-scarce cobalt in nickel-manganese-cobalt (NMC) based cathodes raises significant supply chain and sustainability concerns. Despite numerous attempts to address these issues, eliminating Co has remained elusive, yet to be commercially realized because doing so detrimentally affects the layering and cycling stability of NMC cathodes. We report here an alternative solution using Co free high-Ni Li1 xNi0.95Mn0.05O2 (NM9505) with a Li-deficient composite structure that outperforms the stoichiometric layer-structured counterparts. Through correlated synchrotron X-ray characterization and multiscale modeling, we show that Li-deficiency plays a predominant role in hindering crystallization and interparticle fusion during calcination, resulting in intergrown rocksalt and layered phases within the composite. As such, the anisotropic lattice expansion and contraction is suppressed in Li-deficient NM9505 upon cycling, offering 90% first-cycle Coulombic efficiency, 90% capacity retention, and close-to-zero voltage fade for 100 cycles up to 4.4 V. Our findings represent an important step forward in addressing the critical Co-reliance issues, and offer new opportunities for designing high-performing Co-free cathodes for sustainable Li-ion batteries.

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The effect of lithium-excess on Ni-rich LiNi0.6Co0.2Mn0.2O2 cathode materials prepared by a Taylor flow reactor

Cited by 13 publications

References 62 publications

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

PVP-Assisted Hydrothermal Synthesis of Nickel-Rich Cobalt-Free Single-Crystal LiNi_0.9Mn_0.05Al_0.05O₂ for Lithium-Ion Batteries

Stabilizing Cobalt-Free Cathodes with Lithium-Stoichiometry Control for Sustainable Lithium-ion Batteries

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The effect of lithium-excess on Ni-rich LiNi0.6Co0.2Mn0.2O2 cathode materials prepared by a Taylor flow reactor

Cited by 13 publications

References 62 publications

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi0.9Co0.05Mn0.05O2 Cathode Materials for Li-Ion Batteries

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi0.9Co0.05Mn0.05O2 Cathode Materials for Li-Ion Batteries

PVP-Assisted Hydrothermal Synthesis of Nickel-Rich Cobalt-Free Single-Crystal LiNi0.9Mn0.05Al0.05O2 for Lithium-Ion Batteries

Stabilizing Cobalt-Free Cathodes with Lithium-Stoichiometry Control for Sustainable Lithium-ion Batteries

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Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

Effect of Li Excess on Electrochemical Performance of Ni-Rich LiNi_0.9Co_0.05Mn_0.05O₂ Cathode Materials for Li-Ion Batteries

PVP-Assisted Hydrothermal Synthesis of Nickel-Rich Cobalt-Free Single-Crystal LiNi_0.9Mn_0.05Al_0.05O₂ for Lithium-Ion Batteries