LiF-Dominated SEI Formation via a Lychee-Like Primary Interphase for Fast-Charging Natural Graphite Anodes.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Natural graphite is a key anode material in lithium-ion batteries due to cost and performance.
• Challenges include poor electrolyte compatibility, leading to capacity fade and reduced efficiency.
• Existing TiO_2-x coatings improve stability but limit fast-charging due to fragile SEI.

Purpose of the Study:

• To enhance the fast-charging capability of natural graphite anodes.
• To improve the structural integrity and cycling stability of lithium-ion battery anodes.
• To develop a robust solid-electrolyte interphase (SEI) for better interfacial management.

Main Methods:

• Incorporation of nitrogen atoms into oxygen-deficient titanium dioxide (TiO_2-x) surface structures.
• Formation of a lychee-like primary interphase to regulate interfacial electrochemistry.
• Analysis using ex situ X-ray photoelectron spectroscopy and kinetic evaluations.

Main Results:

• A robust LiF-dominated SEI was successfully formed on the modified anodes.
• The LiF-dominated SEI effectively mitigated interfacial side reactions and enhanced charge transfer.
• Modified anodes showed improved capacities at high current densities, retaining 388.9 mAh g^-1 after 200 cycles at 5 C.

Conclusions:

• Nitrogen incorporation into TiO_2-x coatings is a viable strategy for improving natural graphite anode performance.
• The developed SEI enhances cycling stability and fast-charging capabilities in lithium-ion batteries.
• This approach offers a pathway to more durable and efficient energy storage solutions.