Enhanced Performance of Li‐Rich Manganese Oxide Cathode Synergistically Modificated by F‐Doping and Oleic Acid Treatment

Dong, Haotian; Jiang, Danfeng; Xing, Shengzhou; Zhao, Lina; Hu, Lei; Mao, Jing; Zhang, Haitao

doi:10.1002/smll.202307156

Cited by 4 publications

(1 citation statement)

References 65 publications

(45 reference statements)

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“…To address these challenges and elevate the electrochemical characteristics of LLOs, scientists have used different methods, like doping (e.g., F, , Mg, , and Al , ), coating (e.g., Al 2 O 3 and Li 3 PO 4 ), and surface modification. While these modifications have demonstrated improvements in specific aspects of the LLO performance, they are not capable of addressing multiple material defects simultaneously.…”

Section: Introductionmentioning

confidence: 99%

In Situ Surface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization

Su,

Guo,

Xie

et al. 2024

ACS Appl. Mater. Interfaces

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Li-rich Mn-based cathode materials (LLOs) are often faced with problems such as low initial Coulombic efficiency (ICE), limited rate performance, voltage decay, and structural instability. Addressing these problems with a single approach is challenging. To overcome these limitations, we developed an LLO with surface functionalization using a simple fabrication method. This two-step process involved a liquid-stage NaBF 4 treatment followed by an in situ chemical reaction during sintering. This reaction led to the creation of oxygen vacancies (O V ), spinel structures, and doping with Na at the Li site, B at the tetrahedral interstitial spaces of O in both the transition-metal (TM) layer and Li layers as well as the octahedral interstices in the TM layer, and F at the O site. We have carried out a thorough study and employed density functional theory calculations to reveal the hidden mechanisms. The treatment not only increases the electrical conductivity but also changes the oxygen charge environment and inhibits lattice oxygen activity. Surprisingly, the B−O bond is so strong that it prevents the migration of TM within the tetrahedral interstitial spaces of O in both the TM and Li layers, hence stabilizing its structure. This bonding interaction strengthens the transition of the TM 3d and O 2p states to lower energy levels, thus causing an increase in the redox potentials. Hence, a rise in the operating voltage occurs. Of special importance, this therapy dramatically increases the ICE to 90.29% and keeps a specified capacity of 203.3 mAh/g after 100 cycles at 1C, which is an excellent capacity retention of 89.94%. This study introduces ideas and methods to tackle the challenges associated with LLOs in batteries. It also provides compelling evidence for the development of high-energy-density Li-ion batteries.

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Section: Introductionmentioning

confidence: 99%

In Situ Surface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization

Su,

Guo,

Xie

et al. 2024

ACS Appl. Mater. Interfaces

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Band Structure Engineering Promotes Anionic Redox Reversibility of Cobalt‐Free Li‐Rich Layered Oxides Cathodes

Gao,

Guo,

et al. 2024

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Li‐rich layered oxides cathodes (LLOs) have prevailed as the promising high‐energy‐density cathode materials due to their distinctive anionic redox chemistry. However, uncontrollable anionic redox process usually leads to structural deterioration and electrochemical degradation. Herein, a Mo/Cl co‐doping strategy is proposed to regulate the relative position of energy band for modulating the anionic redox chemistry and strengthening the structural stability of Co‐free Li1.16Mn0.56Ni0.28O2 cathodes. The incorporation of Mo with high d state orbit and Cl with low electronegativity can narrow the band energy gap between bonding and antibonding bands via increasing the filled lower‐Hubbard band (LHB) and decreasing the non‐bonding O 2p energy bands, promoting the anionic redox reversibility. In addition, strong covalent Mo─O and Mn─Cl bonding further increases the covalency of Mn─O band to further stabilize the O2n− species and enhance the reversible distortion of MnO6 octahedron. The strengthening electronic conductivity, together with the epitaxial structure Li2MoO4 facilitates the fast Li+ kinetics. As a result, the dual doping material exhibits enhanced anionic redox reversibility and suppressed oxygen release with increased cyclic stability and excellent rate performance. This strategy provides some guidance to design high‐energy‐density LLOs with desirable anionic redox reversibility and stable crystal structure via band structure engineering.

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Boosting rate performance of layered lithium-rich cathode materials by oxygen vacancy induced surface multicomponent integration

Fang,

Su,

Dong

et al. 2024

Journal of Energy Chemistry

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Enhanced Performance of Li‐Rich Manganese Oxide Cathode Synergistically Modificated by F‐Doping and Oleic Acid Treatment

Cited by 4 publications

References 65 publications

In Situ Surface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization

In Situ Surface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization

Band Structure Engineering Promotes Anionic Redox Reversibility of Cobalt‐Free Li‐Rich Layered Oxides Cathodes

Boosting rate performance of layered lithium-rich cathode materials by oxygen vacancy induced surface multicomponent integration

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