Anionic redox induced anomalous structural transition in Ni-rich cathodes

Liu, Jue; Du, Zhijia; Wang, Xuelong; Tan, Sha; Geng, Linxiao; Song, Bang‐Sup; Chien, Po‐Hsiu; Everett, S. Michelle; Hu, Enyuan

doi:10.1039/d1ee02987h

Cited by 51 publications

(54 citation statements)

References 88 publications

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“…Liu et al [ 51 ] also revealed a common four-stage structural transition in Ni-rich cathodes by using high throughput operando neutron diffraction. In particular, they found that the Ni-rich cathodes had a universal structural evolution during about 75% delithiation, regardless of the nickel content or the substituent content.…”

Section: Challenges Of Ni-rich Cathode Materials Under High Voltagementioning

confidence: 99%

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Liao

Liu

2022

Nanomaterials

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Ni-rich cathode materials have become promising candidates for lithium-based automotive batteries due to the obvious advantage of electrochemical performance. Increasing the operating voltage is an effective means to obtain a higher specific capacity, which also helps to achieve the goal of high energy density (capacity × voltage) of power lithium-ion batteries (LIBs). However, under high operating voltage, surface degradation will occur between Ni-rich cathode materials and the electrolytes, forming a solid interface film with high resistance, releasing O2, CO2 and other gases. Ni-rich cathode materials have serious cation mixing, resulting in an adverse phase transition. In addition, the high working voltage will cause microcracks, leading to contact failure and repeated surface reactions. In order to solve the above problems, researchers have proposed many modification methods to deal with the decline of electrochemical performance for Ni-rich cathode materials under high voltage such as element doping, surface coating, single-crystal fabrication, structural design and multifunctional electrolyte additives. This review mainly introduces the challenges and modification strategies for Ni-rich cathode materials under high voltage operation. The future application and development trend of Ni-rich cathode materials for high specific energy LIBs are projected.

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Section: Challenges Of Ni-rich Cathode Materials Under High Voltagementioning

confidence: 99%

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Liao

Liu

2022

Nanomaterials

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“…For the low-resolution frames (bank 2 and 3), a back-to-back exponential function convoluted with a symmetrical Gaussian function was used to describe the peak profile. For the high-resolution frames (bank 4 and 5), the moderator induced line profile was modeled using a modified Ikeda-Carpenter-David function [51,52]. The Lorenz factor was accounted for by multiplying (d 4 ) [53].…”

Section: Neutron Diffractionmentioning

confidence: 99%

Double Paddle-Wheel Enhanced Sodium Ion Conduction in an Antiperovskite Solid Electrolyte

Tsai

Mair

Smith

et al. 2022

Preprint

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Antiperovskite (AP) structure compounds (X3AB, where X is an alkali cation and A and B are anions) have the potential for highly correlated motion between the cation and a cluster anion on the A or B site. This so-called “paddle-wheel” mechanism may be the basis for enhanced cation mobility in solid electrolytes. Here we show, through combined experiments and modeling, the first instance of a double paddle-wheel mechanism, leading to fast sodium ion conduction in the antiperovskite Na3-xO1-x(NH2)x(BH4). As the concentration of amide (NH2-) cluster anions is increased, large positive deviations in ionic conductivity above that predicted from a vacancy diffusion model are observed. Using EIS, PXRD, synchrotron XRD, neutron diffraction, AIMD, and NMR, we characterize the cluster anion rotational dynamics, and find that cation mobility is influenced by the rotation of both NH2- and BH4- species, resulting in sodium ion conductivity a factor of 102 higher at x = 1 than expected for the vacancy mechanism alone. Generalization of this phenomenon to other compounds could accelerate fast ion conductor exploration and design.

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“…First, researchers have mainly focused on the cumulative gas evolution after many cycles or at elevated temperature conditions, but have rarely explored the relationship between oxygen release and gas evolution during a single cycle. [32,33] In fact, when charging to a higher voltage, especially under overcharge conditions, a multitude of reactive oxygen species will appear conspicuously and O 2 will even evolve. [31,[34][35][36] Second, in terms of the analysis of the structural change during the electrochemical process, only some regional measurements that are limited to a certain length scale have been performed, where the local structures of oxygen release are not detected.…”

Section: Introductionmentioning

confidence: 99%

Investigation and Suppression of Oxygen Release by LiNi_0.8Co_0.1Mn_0.1O₂ Cathode under Overcharge Conditions

Shi

Peng

Dai

et al. 2022

Advanced Energy Materials

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The safety issue of lithium‐ion batteries is a crucial factor limiting their large‐scale application. Therefore, it is of practical significance to evaluate the impact of their overcharge behavior because of the severe levels of oxygen release of cathode materials during this process. Herein, by combining a variety of in situ techniques of spectroscopy and electron microscopy, this work studies the structural degradation of LiNi0.8Co0.1Mn0.1O2 (NCM811) accompanying the oxygen release in the overcharge process. It is observed that a small amount of O2 evolves from the initial surface at ≈4.7 V. When charging to a higher voltage (≈5.5 V), a large amount of O2 evolves on the newly formed surface due to the occurrence of microcracks. Based on experimental results and theoretical calculations, it is determined that the oxygen release mainly occurs in the near‐surface regions, where the remaining oxygen vacancies accumulate to create voids. To suppress the oxygen release, single‐crystalline NCM811 with integrated structure is introduced and serves as a cathode, which can effectively inhibit morphology destruction and reduce the activation of lattice oxygen in the surface region. These findings provide a theoretical basis and effective strategy for improving the safety performance of Ni‐rich cathode materials in practical applications.

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Anionic redox induced anomalous structural transition in Ni-rich cathodes

Abstract: Ni-rich cathodes have emerged as one of the most promising candidates to power next generation electric vehicles. However, they often suffer from poor capacity retention when charged to high voltages...

Cited by 51 publications

References 88 publications

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Double Paddle-Wheel Enhanced Sodium Ion Conduction in an Antiperovskite Solid Electrolyte

Investigation and Suppression of Oxygen Release by LiNi_0.8Co_0.1Mn_0.1O₂ Cathode under Overcharge Conditions

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Anionic redox induced anomalous structural transition in Ni-rich cathodes

Abstract: Ni-rich cathodes have emerged as one of the most promising candidates to power next generation electric vehicles. However, they often suffer from poor capacity retention when charged to high voltages...

Cited by 51 publications

References 88 publications

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage

Double Paddle-Wheel Enhanced Sodium Ion Conduction in an Antiperovskite Solid Electrolyte

Investigation and Suppression of Oxygen Release by LiNi0.8Co0.1Mn0.1O2 Cathode under Overcharge Conditions

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Product

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About

Investigation and Suppression of Oxygen Release by LiNi_0.8Co_0.1Mn_0.1O₂ Cathode under Overcharge Conditions