Surface engineering enables robust SEI growth towards a stable and efficient lithium-ion battery SiO _x anode

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Commercialization of silicon oxide (SiO_x) anodes is hindered by poor cycling stability and rate capability.
• Uncontrolled solid electrolyte interphase (SEI) growth on SiO_x surfaces leads to performance degradation.

Purpose of the Study:

• To develop a surface engineering strategy for controllable SEI formation on SiO_x anodes.
• To enhance the electrochemical performance of SiO_x anodes for lithium-ion batteries.

Main Methods:

• In situ construction of a dense C-N network on SiO_x nanoparticle surfaces.
• Regulation of surface energy and electronic structure to control SEI composition and growth.
• Characterization of the optimized SEI structure (inner Li₂O, outer LiF/Li₂CO₃) and its impact on ion transport.

Main Results:

• Optimized SEI formation led to a 4-fold reduction in interfacial charge transfer resistance.
• Achieved an initial reversible capacity of 1674 mAh g^-1 for the SiO_x anode.
• Demonstrated excellent cycling stability with high capacity retention (96% after 100 cycles) and superior rate capability (888 mAh g^-1 at 5 A g^-1).

Conclusions:

• The C-N network surface engineering strategy effectively controls SEI formation, enhancing SiO_x anode performance.
• The developed method is low-cost, scalable, and suitable for industrial applications.
• This approach offers a promising pathway for producing high-performance SiO_x anodes for next-generation batteries.