High Voltage Ga-Doped P2-Type Na2/3Ni0.2Mn0.8O2 Cathode for Sodium-Ion Batteries
Küçük Resim Yok
Tarih
2024
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
John Wiley and Sons Inc
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Ni/Mn-based oxide cathode materials have drawn great attention due to their high discharge voltage and large capacity, but structural instability at high potential causes rapid capacity decay. How to moderate the capacity loss while maintaining the advantages of high discharge voltage remains challenging. Herein, the replacement of Mn ions by Ga ions is proposed in the P2-Na2/3Ni0.2Mn0.8O2 cathode for improving their cycling performances without sacrificing the high discharge voltage. With the introduction of Ga ions, the relative movement between the transition metal ions is restricted and more Na ions are retained in the lattice at high voltage, leading to an enhanced redox activity of Ni ions, validated by ex situ synchrotron X-ray absorption spectrum and X-ray photoelectron spectroscopy. Additionally, the P2-O2 phase transition is replaced by a P2-OP4 phase transition with a smaller volume change, reducing the lattice strain in the c-axis direction, as detected by operando/ex situ X-ray diffraction. Consequently, the Na2/3Ni0.21Mn0.74Ga0.05O2 electrode exhibits a high discharge voltage close to that of the undoped materials, while increasing voltage retention from 79% to 93% after 50 cycles. This work offers a new avenue for designing high-energy density Ni/Mn-based oxide cathodes for sodium-ion batteries. © 2023 Wiley-VCH GmbH.
Açıklama
Anahtar Kelimeler
Ga-doped, high-voltage cathodes, layered oxide cathodes, phase transition, sodium-ion batteries
Kaynak
Small
WoS Q Değeri
Scopus Q Değeri
Q1
Cilt
20
Sayı
17
