Oxygen vacancy chemistry in oxide cathodes

Zhang, Yu-Han; Zhang, Shu; Hu, Naifang; Liu, Yuehui; Ma, Jun; Han, Pengxian; Hu, Zhiwei; Wang, Xiaogang; Cui, Guanglei

doi:10.1039/d3cs00872j

Cited by 30 publications

(2 citation statements)

References 214 publications

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“…Here, all characterization techniques consistently validate that the oxygen redox mechanism at the HVP region is based on the existence of Mn 4+ , which is consistent with the results of analogous oxygen redox materials. 6,17,29,39 We further explored the source of the electrochemical behavior underlying charge transfer in Mn–O–Mn from the phase dimension.…”

Section: Resultsmentioning

confidence: 99%

A prismatic alkali-ion environment suppresses plateau hysteresis in lattice oxygen redox reactions

Yu,

Gao,

Rong

et al. 2024

Energy Environ. Sci.

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Section: Resultsmentioning

confidence: 99%

A prismatic alkali-ion environment suppresses plateau hysteresis in lattice oxygen redox reactions

Yu,

Gao,

Rong

et al. 2024

Energy Environ. Sci.

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“…However, the high nickel content easily triggers poor cycling stability and thermal stability, hindering the practical application of nickel-rich cathode materials. Due to the significant overlap of O-p/TM-d orbitals, complete oxidation of Ni ions during charging can lead to partial oxidation of oxygen anions into high-valence oxygen species (O n – , 0 ≤ n < 2) and even oxygen molecules. − More importantly, irreversible oxygen redox will lead to serious problems such as transition metal migration, surface structure degradation, stress accumulation, intracrystalline cracks, rapid electrochemical performance decay, and thermal instability. , Hence, regulating the stability of lattice oxygen is the key to achieving a high-energy-density 811 cathode.…”

Section: Introductionmentioning

confidence: 99%

Regulating the Charge Distribution of Oxygen by High-Entropy Doping to Stabilize Single-Crystal Ni-Rich Cathode Materials

Gao,

Zhou,

Dai

et al. 2024

ACS Appl. Energy Mater.

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Single-crystal Ni-rich ternary cathode materials (811), with their comprehensive advantage of high energy density and low manufacturing cost, have been considered the most promising materials for Li-ion batteries. Due to strong O-p/TM-d covalent hybridization, the complete oxidation of Ni ions during electrochemical cycling is often accompanied by inevitable oxygen loss, resulting in an irreversible surface phase transition, accumulated lattice stress, and poor thermal stability. Considering the fact that introducing heteroatoms into traditional doping systems can alter the electron density distribution around coordinated oxygen, compositionally complex systems based on high-entropy doping may have a more significant effect on stabilizing lattice oxygen. Herein, the high-entropy doping strategy was applied to design and synthesize single-crystal NCM811 cathodes (HE811) through the molten salt method. Compared to 811, HE811 cathodes show an excellent initial Coulombic efficiency of 90.74% at 0.2C and deliver a higher capacity retention of 80.79% after 300 cycles at 1C between 2.8 and 4.3 V. Owing to high-entropy doping, the oxygen electron densities around multidopants are increased, inhibiting the excessive oxidation of lattice oxygen and improving the stability of TMO 6 coordination structures. This work could provide insights into the high-entropy doping effects in modulating oxygen charge distribution to design high-energydensity Ni-rich ternary cathode materials with long-term cycling.

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Metalloid Phosphorus Induces Tunable Defect Engineering in High Entropy Oxide Toward Advanced Lithium‐Ion Batteries

Lu,

Kang,

Dong

et al. 2024

Adv Funct Materials

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The inferior electrical conductivity and sluggish lithium storage kinetics of conventional high‐entropy oxide (HEO) are critical issues hindering their commercialization. The high electronegativity of metalloids can ameliorate this predicament by altering the electronic configuration of HEO compared to metals. Herein, metalloid phosphorus doping in spinel‐type HEO (PxA1‐x)B2O4 (A/B = Cr, Mn, Fe, Co, Ni) (P‐HEO) is achieved through a facile sol–gel process. The metalloid phosphorus doping facilitates the transfer of electrons from transition metal sites to phosphorus‐doped sites, resulting in the formation of electron‐rich and electron‐deficient local regions on the HEO surface and is conducive to an increase in the total number of active lithium sites in the electrochemical reaction process. Density functional theory calculation reveals Li adsorption energy on the synthesized P‐HEO is only −1.102 eV, demonstrating that the phosphorus doping enables a strong electronic coupling between lithium ions and P‐HEO. Furthermore, metalloid phosphorus doping also leads to oxygen vacancies formation and lattice distortion, which significantly enhances charge transfer efficiency and diffusion kinetics and results in the enhanced lithium storage performance with impressive rate capability and long‐term stability. These findings provide valuable insights for the design of lattice‐engineered HEO as versatile electrodes for future energy storage applications.

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Oxygen vacancy chemistry in oxide cathodes

Abstract: This review focuses on the chemical thermodynamics and reaction kinetics of intrinsic and anionic redox-mediated oxygen vacancies in oxide cathodes.

Cited by 30 publications

References 214 publications

A prismatic alkali-ion environment suppresses plateau hysteresis in lattice oxygen redox reactions

A prismatic alkali-ion environment suppresses plateau hysteresis in lattice oxygen redox reactions

Regulating the Charge Distribution of Oxygen by High-Entropy Doping to Stabilize Single-Crystal Ni-Rich Cathode Materials

Metalloid Phosphorus Induces Tunable Defect Engineering in High Entropy Oxide Toward Advanced Lithium‐Ion Batteries

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