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Abstract Layered oxide cathode with a Li‐O‐vacancy configuration offers high capacity by leveraging additional oxygen redox reactions. However, it faces severe challenges of sluggish kinetics of oxygen redox reactions and lattice oxygen loss, resulting in slow Li+diffusion and rapid electrochemical degradation. Herein, Ti is introduced as electrochemical inactive element into Li‐O‐vacancy configuration to form Mn/vacancy/Ti arrangement within transition metal layers of layered oxide, achieving a marked increase in average output voltage at high current density compared with Ti‐free counterpart. Not only voltage hysteresis between charge and discharge processes can be significantly reduced, but rate capability can be heightened in Li4/7[□1/7Ti1/7Mn5/7]O2by means of retrained over‐potential and improved Li+diffusivity. Furthermore, theoretical calculations suggest that these improvements stem from Ti substitution, which elongates the Li─O bond and lowers the Li+migration energy barrier. Besides, in situ differential electrochemical mass spectrometry and soft X‐ray absorption spectroscopy reveal the modified Li‐O‐vacancy configuration enables reversible anionic and cationic redox behaviors during cycling. These findings provide a promising strategy for tailoring oxygen redox activity and accelerating Li+diffusion kinetics in layered cathode materials with oxygen redox chemistry.
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Improving the electrochemical performance of Li 4 Ti 5 O 12 anode by phosphorus reduction at a relatively low temperature
A novel and efficient method is demonstrated to improve the electrochemical performance of Li 4 Ti 5 O 12 and metal-oxide anodes. In contrast to other methods, inexpensive red phosphorus powder is used as a reducing reagent, and the reduction is conducted at a relatively low temperature of 400 °C. This method offers a low cost and effective way for Li 4 Ti 5 O 12 and metal-oxide anode applications.
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- Award ID(s):
- 1808517
- PAR ID:
- 10136460
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 54
- Issue:
- 100
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 14120 to 14123
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C8CC07026A
