Whole-Voltage-Range Solid-Solution Reaction in Layered Oxide Cathode of Sodium-Ion Batteries
- Nankai University, Tianjin (China)
- Nankai University, Tianjin (China); Haihe Laboratory of Sustainable Chemical Transformations, Tianjin (China)
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Shanghai Jiao Tong Univ. (China)
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 Mn3+ induces severe distortion of MnO6 octahedra, and the resultant low symmetry is responsible for the gliding of MnO2 layers and then inferior multiple-phase transitions upon Na+ extraction/insertion. Here, hexagonal P2-Na0.643Li0.078Mn0.827Ti0.095O2 is synthesized through the incorporation of Li and Ti into the distorted orthorhombic P'2-Na0.67MnO2 to function as a phase-transition-free oxide cathode. Further, 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 eg 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).
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Natural Science Foundation of China (NSFC); Tianjin Natural Science Foundation
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 2403518
- Alternate ID(s):
- OSTI ID: 2229189
- Journal Information:
- Small, Journal Name: Small Journal Issue: 49 Vol. 19; ISSN 1613-6810
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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