Precise Chemical Lithiation: A Pathway to Superior Li-Enriched Li_1+xNCM523 Cathodes for Long Life Anode-Free Li Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Anode-free lithium metal batteries (AFLMBs) require lithium-enriched cathodes like Li_1+xNCM523 for extended cycling life.
• Traditional prelithiation methods (electrochemical, chemical) suffer from limitations like laboratory confinement, excessive lithiation, and structural degradation.

Purpose of the Study:

• To develop a precise chemical lithiation strategy for Li_1+xNCM523 cathodes using a novel reagent.
• To achieve uniform and controllable lithium insertion, enhancing the performance of AFLMBs.

Main Methods:

• Utilized 9-fluorenone lithium (FL-2Li) as a chemical lithiation reagent, chosen for its specific redox potential (1.32 V vs Li⁺/Li).
• Strategically matched FL-2Li's potential to enable tolerable overlithiation while preventing excessive lithiation and structural collapse in Li_1+xNCM523.
• Fabricated and tested Cu||Li_1.7NCM523 anode-free cells using the chemically prelithiated cathode.

Main Results:

• Achieved a homogeneous, bulk-lithiated Li_1.7NCM523 structure, eliminating core-shell effects common with other reagents.
• Demonstrated superior electrochemical performance with 86.16% capacity retention after 100 cycles at 1C in anode-free cells.
• The FL-2Li reagent's potential effectively controlled lithiation, preventing irreversible structural damage.

Conclusions:

• Established a precise chemical lithiation strategy using FL-2Li for high-performance lithium-enriched cathodes.
• Provided a versatile framework for selecting lithiation reagents, offering insights for scalable cathode design.
• The developed method shows potential for advancing battery technology in electric vehicles and energy storage systems.