Redox-couple investigations in Si-doped Li-rich cathode materials

Nation, Leah; Wu, Yan; Liu, Xiaoming; Chi, Miaofang; Wu, Yuehua; Qi, Yue; Sheldon, Brian W.

doi:10.1039/d0cp05737a

Cited by 7 publications

(8 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[15] It is confirmed that the undesirable structural degeneration starts from the surface to the bulk for Li-rich Mn-based oxides. [16,17] One recent study declares that localized O 2 acts as the oxidation product of lattice oxygen. [18] Compared with the material bulk, O 2 first escapes from the surface, thus exacerbating the lattice destruction of the material surface.…”

mentioning

confidence: 99%

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes

Chai

Zhang

et al. 2022

Small

View full text Add to dashboard Cite

High‐capacity Li‐rich Mn‐based oxide cathodes show a great potential in next generation Li‐ion batteries but suffer from some critical issues, such as, lattice oxygen escape, irreversible transition metal (TM) cation migration, and voltage decay. Herein, a comprehensive structural modulation in the bulk and surface of Li‐rich cathodes is proposed through simultaneously introducing oxygen vacancies and P doping to mitigate these issues, and the improvement mechanism is revealed. First, oxygen vacancies and P doping elongates OO distance, which lowers the energy barrier and enhances the reversible cation migration. Second, reversible cation migration elevates the discharge voltage, inhibits voltage decay and lattice oxygen escape by increasing the Li vacancy‐TM antisite at charge, and decreasing the trapped cations at discharge. Third, oxygen vacancies vary the lattice arrangement on the surface from a layered lattice to a spinel phase, which deactivates oxygen redox and restrains oxygen gas (O2) escape. Fourth, P doping enhances the covalency between cations and anions and elevates lattice stability in bulk. The modulated Li‐rich cathode exhibits a high‐rate capability, a good cycling stability, a restrained voltage decay, and an elevated working voltage. This study presents insights into regulating oxygen redox by facilitating reversible cation migration and suppressing O2 escape.

show abstract

mentioning

confidence: 99%

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes

Chai

Zhang

et al. 2022

Small

View full text Add to dashboard Cite

show abstract

“…17 Compared to the abundance of metal cations available for doping, the existing catalyst modification studies on doping of non-metal cations are less extensive and mostly focus on the elements B, 18,19 N, 20,21 P 22,23 and Si. 24,25 On the other hand, anionic doping has also been used in recent years to create OVs and generates several interesting properties and basic anions available for doping are essentially non-metal anions. 11,12,26 For example, when Cl À is substituted for O 2 À , metal-oxygen covalency may increase, which is beneficial for charge transfer in electrocatalytic processes.…”

Section: Choice Of Dopant Ionsmentioning

confidence: 99%

The roles of the oxygen vacancies caused by the ion doping method in catalytic materials and their applications in advanced oxidation processes

Nie,

Lai,

et al. 2023

New J. Chem.

View full text Add to dashboard Cite

show abstract

“…In fact, partial substitution of inactive Ti in the Na‐layered oxides has been studied by a few groups in Na layered oxides and shown to have positive outcomes in terms of lessening structure evolution, [ 21 ] reducing lattice strain, [ 22 ] increasing voltage/capacity retention, [ 23 ] and improving reversibility of TM/O migration during sodiation/de‐sodiation process. [ 24 ] A few studies in Li‐rich layered oxides have indicated that Si in TM sites can reduce the O 2p band of the Fermi level, [ 25 ] promote the formation of oxygen vacancies, [ 26 ] and decrease the covalency degree between TM‐O allowing greater reversibility of anionic redox. [ 27 ] However, to our best knowledge, there is no report on the role of Si as dopants in Na layered oxides.…”

Section: Introductionmentioning

confidence: 99%

Achieving High Stability and Performance in P2‐Type Mn‐Based Layered Oxides with Tetravalent Cations for Sodium‐Ion Batteries

Vanaphuti

Yao

Liu

et al. 2022

Small

View full text Add to dashboard Cite

P2‐type sodium‐manganese‐based layered cathodes, owing to their high capacity from both cationic and anionic redox, are a potential candidate for Na‐ion batteries (NIBs) to replace Li‐ion technology in certain applications. Still, the structure instability originating from irreversible oxygen redox at high voltage remains a challenge. Here, a high sustainability cobalt‐free P2‐Na0.72Mn0.75Li0.24X0.01O2 (X = Ti/Si) cathode is developed. The outstanding capacity retention and voltage retention after 150 cycles are obtained in half‐cells. The finding shows that Ti localizes on the surface while Si diffuses to the bulk of the particles. Thus, Ti can act as a protective layer that alleviates side reactions in carbonate‐based electrolyte. Meanwhile, Si can regulate the local electronic structure and suppress oxygen redox activities. Notably, full‐cells with hard carbon (≈300–335 W h kg−1 based on the cathode mass) deliver the capacity retention of 83% for P2‐Na0.72Mn0.75Li0.24Si0.01O2 and 66% for P2‐Na0.72Mn0.75Li0.24Ti0.01O2 after 500 cycles; this electrochemical stability is the best compared to other reported cathodes based on oxygen redox at present. The superior cycle performance also stems from the ability to inhibit microcracking and planar gliding within the particles. Altogether, this finding offers a new composition for developing high‐performance low‐cost cathodes for NIBs and highlights the unique role of Ti/Si ions.

show abstract

Redox-couple investigations in Si-doped Li-rich cathode materials

Abstract: Si doping improves the electrochemical behavior of Li-rich cathodes during the activation cycle by changing the operative redox couples.

Cited by 7 publications

References 36 publications

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes

The roles of the oxygen vacancies caused by the ion doping method in catalytic materials and their applications in advanced oxidation processes

Achieving High Stability and Performance in P2‐Type Mn‐Based Layered Oxides with Tetravalent Cations for Sodium‐Ion Batteries

Contact Info

Product

Resources

About

Redox-couple investigations in Si-doped Li-rich cathode materials

Abstract: Si doping improves the electrochemical behavior of Li-rich cathodes during the activation cycle by changing the operative redox couples.

Cited by 7 publications

References 36 publications

Facilitating Reversible Cation Migration and Suppressing O2 Escape for High Performance Li‐Rich Oxide Cathodes

Facilitating Reversible Cation Migration and Suppressing O2 Escape for High Performance Li‐Rich Oxide Cathodes

The roles of the oxygen vacancies caused by the ion doping method in catalytic materials and their applications in advanced oxidation processes

Achieving High Stability and Performance in P2‐Type Mn‐Based Layered Oxides with Tetravalent Cations for Sodium‐Ion Batteries

Contact Info

Product

Resources

About

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes

Facilitating Reversible Cation Migration and Suppressing O₂ Escape for High Performance Li‐Rich Oxide Cathodes