Investigations of the capacity fading mechanism of Na0.44MnO2via ex situ XAS and magnetization measurements
Küçük Resim Yok
Tarih
2018
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Royal Soc Chemistry
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Na-ion batteries represent a promising complementary alternative to Li-ion batteries due to their high energy density and natural abundancy of Na. However, these batteries have short cycle life and extensive research activities on these batteries are required to understand the mechanism of such drawbacks. In this report, we investigate the capacity fading mechanism of Na(0.44)MnO(2)via ex situ X-ray diffraction, X-ray absorption spectroscopy, Fourier transform infrared spectroscopy and magnetization measurements. Our results show that the unit cell volume, the effective mass of Mn-O bonds, the number of Mn4+ ions and the effective magnetic moment decrease upon repeated cycling. We propose that some Mn4+ ions in the octahedral environment become Mn3+ ions in a square pyramidal environment, causing oxygen release upon cycling. Any free oxygen in the battery is expected to react with the electrolyte and cause capacity fade.
Açıklama
Anahtar Kelimeler
Sodium-Ion Batteries, Manganese Oxide, Cathode Material, Na0.44mno2, Crystal, Electrodes, Nanowires
Kaynak
Dalton Transactions
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
47
Sayı
47
