Two-Dimensional Beidellite/Carbon Superlattice for Boosting Lithium-Ion Storage Performance.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Layered silicates are promising anode materials for lithium-ion batteries (LIBs).
• Improving their electrochemical performance requires advanced structural modification and hybridization techniques.
• Existing materials often face challenges with rate capability and long-term cycling stability.

Purpose of the Study:

• To develop a novel two-dimensional Fe-beidellite/carbon (Fe-BEI@C) superlattice-like heterostructure.
• To enhance the lithium storage performance of Fe-BEI by introducing interlaminar and superficial carbon coating.
• To investigate the electrochemical behavior and lithium-ion dynamics within the Fe-BEI@C heterostructure.

Main Methods:

• Preparation of Fe-BEI@C via glucose intercalation and calcination.
• Fabrication of Fe-BEI@C/Li half cells for electrochemical testing.
• Analysis of electrochemical performance including specific capacity, rate capability, and cycling stability.
• Investigation of Li+ diffusion coefficients and reaction kinetics (surface vs. diffusion control).

Main Results:

• The Fe-BEI@C anode delivered a maximum specific capacity of 850 mAh·g⁻¹ at 0.5 A·g⁻¹ with 92.3% retention after 100 cycles.
• High-rate performance was achieved, with 403 mAh·g⁻¹ at 5 A·g⁻¹.
• Reversible valence state changes of Si and Fe occurred without structural collapse.
• A high Li+ diffusion coefficient (10⁻¹³∼10⁻¹⁰ cm² s⁻¹) indicated fast ion transfer.

Conclusions:

• The Fe-BEI@C heterostructure exhibits excellent lithium storage performance, attributed to carbon coating enhancing rate capability and pseudocapacitance.
• The material demonstrates structural stability during electrochemical cycling.
• This work highlights the potential of layered silicates as advanced anode materials for LIBs through molecular-level carbon hybridization.