Eliminating the Mn 3d Orbital Degeneracy to Suppress the Jahn-Teller Distortion for Stable MnO2 Cathode

被引：51

作者：

Hou, Zishan ^{[1
]}

Wang, Jinrui ^{[1
]}

Dai, Ningning ^{[2
]}

Yao, Shuyun ^{[1
]}

Wang, Shiyu ^{[1
]}

Ji, Yingjie ^{[1
]}

Gao, Xueying ^{[1
]}

Zhang, Huiying ^{[1
]}

Tang, Zheng ^{[1
]}

Sun, Yanfei ^{[1
]}

Li, Shuyuan ^{[1
]}

Liu, Yuanming ^{[1
]}

Fu, Weijie ^{[1
]}

Nie, Kaiqi ^{[3
]}

Jiang, Yining ^{[1
]}

Yan, Yi-Ming ^{[1
]}

Yang, Zhiyu ^{[1
]}

机构：

[1] Beijing Univ Chem Technol, Beijing Adv Innovat Ctr Soft Matter Sci & Engn, State Key Lab Organ Inorgan Composites, Beijing 100029, Peoples R China

[2] Dongying Ind Prod Inspection & Metrol Verificat Ct, Dongying 257000, Peoples R China

[3] Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China

来源：

ADVANCED ENERGY MATERIALS | 2024年 / 14卷 / 06期

基金：

中国国家自然科学基金;

关键词：

degenerate ground state; Jahn-Teller distortion; manganese oxides; orbital regulation; BIRNESSITE;

D O I：

10.1002/aenm.202302477

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The cycle stability of manganese-based oxides cathode for sodium-ion supercapacitor is impeded by severe structural collapse due to the Jahn-Teller (J-T) distortion of [MnO6] octahedra as Mn(4+ )is reduced to Mn3+. Herein, MnO2 cathode is stabilized by Mg2+ ions confinement between transition metal slabs. The Mg2+ confinement induces the transformation from original cubic [MnO6] octahedra to compressed configuration (com-MnO2), resulting in the elimination of Mn 3d orbital degeneracy, thereby alleviating the structural deformation of [Mn(3+)O6] octahedra by suppressing J-T distortion during the reduction of Mn4+. As a result, the prepared com-MnO2 exhibits greatly improved cycling stability with 99.1% retention of its initial capacity after 20 000 cycles due to inhibited J-T distortion. Additionally, an enhanced capacity of 434 F g(-1) at 1 A g(-1), a rate capacity of 275 F g(-1 )at 20 A g(-1 )can be achieved by com-MnO2. The in situ XRD, Raman spectra reveal the reversible structural transformation during a cycle. It is concluded that the elimination of Mn 3d orbital degeneracy plays a crucial role in suppressing J-T distortion, which is conducive to in-depth understanding of electron structure of transition metal oxides toward cycling performance.

引用

页数：8