Work-Function-Engineered TiN/N-Doped Carbon Heterostructure for Accelerating Lithium-Ion Transport in Micron-Sized...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon monoxide (SiO) anodes offer high theoretical capacity for lithium-ion batteries.
• Challenges include poor conductivity, slow interfacial kinetics, and unstable solid-electrolyte interphase (SEI).
• Existing heterogeneous coatings face limitations due to interfacial resistance.

Purpose of the Study:

• To design a dual-coated SiO anode that overcomes limitations in conductivity and interfacial kinetics.
• To engineer a built-in electric field (BEF) at the heterointerface for enhanced ion transport.
• To improve fast-charging capabilities and long-term cycling stability of SiO anodes.

Main Methods:

• Fabrication of a dual-coated SiO anode with N-doped carbon (high work function) and TiN (low work function) layers.
• Investigation of the built-in electric field (BEF) effect at the N-doped carbon/TiN heterointerface.
• Electrochemical characterization including rate performance and cycling stability tests.
• Analysis of the SEI layer composition and Li+ migration energy.

Main Results:

• The dual-coated TiN-SiO/C anode exhibited exceptional rate performance, retaining 758 mAh g⁻¹ at 5 A g⁻¹.
• Achieved long-term cycling stability with 694.5 mAh g⁻¹ after 800 cycles at 2 A g⁻¹.
• The BEF promoted directional Li+ transport and fostered an inorganic-rich SEI (LiF/LixTiN) with reduced Li+ migration energy (37.74 kJ mol⁻¹).

Conclusions:

• The work-function-engineered heterointerface strategy effectively reduces interfacial resistance and accelerates ion diffusion.
• The developed dual-coated SiO anode demonstrates significant potential for high-performance, fast-charging lithium-ion batteries.
• This approach offers a promising pathway for designing advanced anode materials by controlling interfacial properties.