Whole‐Voltage‐Range Solid‐Solution Reaction in Layered Oxide Cathode of Sodium‐Ion Batteries

Journal Article · Mon Aug 21 00:00:00 EDT 2023 · Small

DOI:https://doi.org/10.1002/smll.202304187· OSTI ID:2229189

Ren, Meng  ^[1]; Zhu, Zhuo ^[1]; Liang, Zhaohui ^[1]; Huang, Yaohui ^[1]; Zhang, Tong ^[1]; Hou, Machuan ^[1]; Zhang, Kai ^[2]; Chen, Zonghai ^[3]; He, Yushi ^[4]; Ma, Zifeng ^[4]; Chen, Jun ^[2]; Li, Fujun  ^[2]

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1. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center (RECAST) College of Chemistry Nankai University Tianjin 300071 China
2. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Renewable Energy Conversion and Storage Center (RECAST) College of Chemistry Nankai University Tianjin 300071 China, Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300071 China
3. Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Lemont IL 60439 USA
4. Shaoxing Institute of New Energy and Molecular Engineering Shanghai Jiao Tong University Shaoxing 312300 China

Abstract Layered manganese‐based oxides (LMOs) are promising cathode materials for sodium‐ion batteries (SIBs) due to their versatile structures. However, the Jahn–Teller effect of Mn ³⁺ induces severe distortion of MnO ₆ octahedra, and the resultant low symmetry is responsible for the gliding of MnO ₂ layers and then inferior multiple‐phase transitions upon Na ⁺ extraction/insertion. Here, hexagonal P2‐Na _0.643 Li _0.078 Mn _0.827 Ti _0.095 O ₂ is synthesized through the incorporation of Li and Ti into the distorted orthorhombic P'2‐Na _0.67 MnO ₂ to function as a phase‐transition‐free oxide cathode. It is revealed that Li in both the transition‐metal and Na layers enhances the covalency of Mn–O bonds and allows degeneracy of Mn 3d e _g orbitals to favor the formation of hexagonal phase, and the high strength of Ti–O bonds reduces the electrostatic interaction between Na and O for suppressed Na ⁺ /vacancy rearrangements. These collectively lead to a whole‐voltage‐range solid‐solution reaction between 1.8 and 4.3 V with a small volume variation of 1.49%. This rewards its excellent cycling stability (capacity retention of 90% after 500 cycles) and rate capability (89 mAh g ⁻¹ at 2000 mA g ⁻¹ ).

• Sponsoring Organization: USDOE
• OSTI ID: 2229189
• Journal Information: Small, Journal Name: Small Vol. 19 Journal Issue: 49; ISSN 1613-6810
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English