SiOx/C Composite Anode for Lithium-Ion Battery with Improved Performance Using Graphene Quantum Dots and Carbon...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Graphene quantum dots (GQDs) are promising anode materials for secondary batteries.
• Silicon oxide (SiOx) can enhance battery capacity but suffers from volume expansion issues.
• Carbon nanoparticles (CNPs) can act as structural stabilizers.

Purpose of the Study:

• To investigate the effect of varying silicon oxide content (0-30 wt%) on the performance of GQD/SiOx/C composite anode materials.
• To evaluate the role of carbon nanoparticles as a structural stabilizer for silicon oxide in secondary battery anodes.
• To determine the optimal composition for a high-performance GQD-based anode material.

Main Methods:

• Fabrication of GQD/SiOx/C composites with different SiOx wt%.
• Characterization of physical properties using XRD, SEM, and EDS.
• Electrochemical performance testing including charge-discharge cycles, rate capability, and impedance analysis.

Main Results:

• CNPs formed internal cavities, alleviating SiOx volume expansion and ensuring uniform particle distribution.
• Optimal SiOx content was found to be 15 wt%, yielding an initial discharge capacity of 595 mAh/g.
• The 15 wt% SiOx composite demonstrated 92% capacity retention and a rate performance of 81 at 2 C/0.1 C.
• Low initial efficiency was observed at 5 wt% SiOx, and poor cycle stability above 30 wt% SiOx.

Conclusions:

• The GQD/SiOx/C composite with 15 wt% SiOx and CNPs exhibits excellent electrochemical performance for secondary battery anodes.
• Carbon nanoparticles effectively mitigate silicon oxide volume expansion, enhancing anode stability and capacity.
• This composite shows significant potential as a high-efficiency anode material for next-generation energy storage devices.