Formation and thermodynamic stability of oxygen vacancies in typical cathode materials for Li-ion batteries: Density functional theory study

Hu, Wei; Wang, Hewen; Luo, Wenwei; Xu, Bo; Ouyang, Chuying

doi:10.1016/j.ssi.2020.115257

Cited by 50 publications

(32 citation statements)

References 59 publications

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“…For reference, the oxygen-vacancy formation energy for the undoped system was calculated to be −0.12 eV, indicating the spontaneous oxygengas evolution at a highly charged state, which is consistent with previous experimental and theorical works. [28,52,53] However, it was revealed that the lattice-oxygen stability is significantly altered by the presence of dopants; the vacancy formation energies varied over a wide range from 0.16 eV to −1.24 eV depending on the dopant. Al, Si, Mn, Cu, and Ir dopants were observed to substantially increase the oxygen-vacancy formation energy compared with that of the undoped case (−0.12 eV).…”

Section: Resultsmentioning

confidence: 99%

Stepwise Dopant Selection Process for High‐Nickel Layered Oxide Cathodes

Kim

Song

Jung

et al. 2022

Advanced Energy Materials

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NCM‐based lithium layered oxides (LiNi1–x–yCoxMnyO2) have become prevalent cathode materials in state‐of‐the‐art lithium‐ion batteries. Higher energy densities can be achieved in these materials by systematically increasing the nickel content; however, this approach commonly results in inferior cycle stability. The poor cycle retention of high‐nickel NCM cathodes is generally attributed to chemo‐mechanical degradation (e.g., intergranular microcracks), vulnerability to oxygen‐gas evolution, and the accompanying rocksalt phase formation via cation mixing. Herein, the feasibility of doping strategies is examined to mitigate these issues and effective dopants for high‐nickel NCM cathodes are theoretically identified through a stepwise pruning process based on density functional theory calculations. Specifically, a sequential three‐step screening process is conducted for 38 potential dopants to scrutinize their effectiveness in mitigating chemo‐mechanical lattice stress, oxygen evolution, and cation mixing at charged states. Using this process, promising dopant species are selected rationally and a silicon‐doped LiNi0.92Co0.04Mn0.04O2 cathode is synthesized, which exhibits suppressed lattice expansion/contraction, fewer intergranular microcracks, and reduced rocksalt formation on the surface compared with its undoped counterpart, leading to superior electrochemical performance. Moreover, a comprehensive map of dopants regarding their potential applicability is presented, providing rational guidance for an effective doping strategy for high‐nickel NCM cathodes.

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Section: Resultsmentioning

confidence: 99%

Stepwise Dopant Selection Process for High‐Nickel Layered Oxide Cathodes

Kim

Song

Jung

et al. 2022

Advanced Energy Materials

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“…130,142 In particular, DFT studies can provide valuable insight into charge storage mechanisms, including the intercalation and conversion reactions, and structural evolution of various batteries during operation. [143][144][145][146][147][148][149] Therefore, DFT computations can complement and guide experimentation by unveiling the structure-property relationships for a wide range of promising materials, especially focusing on the effect of the chemical structure of COF on electrochemical characteristics. Another powerful simulation method is molecular dynamics (MD) simulation to investigate large-scale structures of COF.…”

Section: Modeling and Simulationsmentioning

confidence: 99%

“…First‐principles approach, namely Density Functional Theory (DFT), has been playing a critical role in understanding fundamental mechanisms of electrochemical processes in novel organic electrode materials by investigating the electronic structures and properties 130,142 . In particular, DFT studies can provide valuable insight into charge storage mechanisms, including the intercalation and conversion reactions, and structural evolution of various batteries during operation 143–149 . Therefore, DFT computations can complement and guide experimentation by unveiling the structure–property relationships for a wide range of promising materials, especially focusing on the effect of the chemical structure of COF on electrochemical characteristics.…”

Section: Modeling and Simulationsmentioning

confidence: 99%

Covalent organic frameworks: Design and applications in electrochemical energy storage devices

Jin

Allam

Jang

et al. 2022

InfoMat

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As an emerging class of crystalline organic material, covalent organic frameworks (COFs) possess uniform porosity, versatile functionality, and precise control over designated structures. Aside from the favorable charge and mass transport pathways offered by the porous framework, COFs can also exhibit designed reversible redox activity. In the past few years, their potential has attracted a great deal of attention for charge storage and transport applications in various electrochemical energy storage devices, and numerous design strategies have been proposed to enhance the corresponding electrochemical properties. This review summarizes the working principle and synthesis methods of COFs and discusses significant findings for supercapacitors and various rechargeable battery systems, emphasizing the representative design strategies and their underlying relationship with electrochemical performances. In addition, key advances achieved by computations are highlighted along with the challenges and prospects in this field.

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“…[27a] O vacancy is usually built on the surface layer of the active materials because the formation energy of O vacancy on the surface is smaller than that in the bulk. [53] There are many methods to construct O vacancies. For example, Qiu et al have reported that the O vacancies can be uniformly generated on the surface regions through a gas-solid interface reaction without destroying the overall structure.…”

Section: Defective Materials On High-capacity Li-based Batteries 31mentioning

confidence: 99%

“…In the vacancy system, O vacancy is widely studied, which can significantly improve the electrochemical properties of LRMC [27a] . O vacancy is usually built on the surface layer of the active materials because the formation energy of O vacancy on the surface is smaller than that in the bulk [53] . There are many methods to construct O vacancies.…”

Section: Defective Materials On High‐capacity Li‐based Batteriesmentioning

confidence: 99%

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

Qiao

Lin

Yan

et al. 2020

Chemistry An Asian Journal

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Current commercial Li-based batteries are approaching their energy density limitation, yet still cannot satisfy the energy density demand of the high-end devices. Hence, it is critical to developing advanced electrode materials with high specific capacity. However, these electrode materials are facing challenges of severe structural degradation and fast capacity fading. Among various strategies, constructing defects in electrode materials holds great promise in addressing these issues. Herein, we summarize a series of significant defect engineering in the high-capacity electrode materials for Li-based batteries. The detailed retrospective on defects specification, function mechanism, and corresponding application achievements on these electrodes are discussed from the view of point, line, planar, volume defects. Defect engineering can not only stabilize the structure and enhance electric/ionic conductivity, but also act as active sites to improve the ionic storage and bonding ability of electrode materials to Li metal. We hope this review can spark more perspectives on evaluating high-energydensity Li-based batteries.

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Formation and thermodynamic stability of oxygen vacancies in typical cathode materials for Li-ion batteries: Density functional theory study

Cited by 50 publications

References 59 publications

Stepwise Dopant Selection Process for High‐Nickel Layered Oxide Cathodes

Stepwise Dopant Selection Process for High‐Nickel Layered Oxide Cathodes

Covalent organic frameworks: Design and applications in electrochemical energy storage devices

Function and Application of Defect Chemistry in High‐Capacity Electrode Materials for Li‐Based Batteries

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