Investigations of the capacity fading mechanism of Na0.44MnO2via ex situ XAS and magnetization measurements

被引：12

作者：

Altin, Serdar ^{[1
]}

Oz, Erdinc ^{[1
,2
]}

Altin, Emine ^{[3
]}

Demirel, Serkan ^{[4
]}

Bayri, Ali ^{[1
]}

Avci, Sevda ^{[5
]}

机构：

[1] Inonu Univ, Phys Dept, TR-44280 Malatya, Turkey

[2] Ankara Univ, Inst Accelerator Technol, TR-06830 Ankara, Turkey

[3] Inonu Univ, IBTAM, TR-44280 Malatya, Turkey

[4] Natl Def Univ, Naval Petty Officer Vocat Sch, Yalova, Turkey

[5] Istanbul Medeniyet Univ, Dept Engn Phys, TR-34000 Istanbul, Turkey

来源：

DALTON TRANSACTIONS | 2018年 / 47卷 / 47期

基金：

欧盟地平线“2020”;

关键词：

SODIUM-ION BATTERIES; MANGANESE OXIDE; CATHODE MATERIAL; NA0.44MNO2; CRYSTAL; ELECTRODES; NANOWIRES;

D O I：

10.1039/c8dt03508c

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

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.

引用

页码：17102 / 17108

页数：7

共 28 条

[1] Hydration-induced spin-glass state in a frustrated Na-Mn-O triangular lattice [J].