Lattice Modulation on Air-Stable Fe-Based Prelithiation Materials with High Capacity via Triggering Anionic Redox...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Li5FeO4 (LFO) shows promise for cathode prelithiation due to dual anionic and cationic redox.
• LFO's practical use is limited by incomplete delithiation and air degradation.
• Effective lithium compensation requires improved material stability and redox activity.

Purpose of the Study:

• To enhance the anionic redox activity and air stability of Li5FeO4 (LFO) through lattice modulation.
• To introduce cobalt into the LFO structure to create a novel cathode material.
• To investigate the electrochemical performance and stability of the cobalt-substituted material.

Main Methods:

• Lattice modulation via cobalt substitution at iron sites in Li5FeO4.
• Synthesis of the novel compound Li5.5Fe0.5Co0.5O4 (LFCO).
• Electrochemical testing including cyclic voltammetry, galvanostatic charge-discharge, and long-term cycling.
• Air stability assessment under controlled humidity.

Main Results:

• Cobalt incorporation facilitates reversible oxygen redox (O2- to O2).
• LFCO exhibits significantly higher specific capacities (860.1 mAh g-1 at 0.1C, 580.0 mAh g-1 at 1C) than LFO.
• LFCO demonstrates enhanced air stability, retaining 520.8 mAh g-1 after 4 days at 20% relative humidity.
• Pouch cells with LFCO show 89.6% capacity retention over 200 cycles.

Conclusions:

• Lattice modulation with cobalt substitution is an effective strategy to improve LFO performance.
• LFCO offers enhanced anionic redox, superior electrochemical capacity, and improved air stability.
• LFCO shows significant potential for next-generation high-energy lithium-ion batteries.