Electrode Engineering of Conversion-based Negative Electrodes for Na-ion Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion (Na-ion) batteries are a cost-effective alternative to lithium-ion (Li-ion) batteries due to sodium's abundance and lower cost.
• Electrode engineering, particularly composition, is critical for Na-ion battery performance, especially for conversion-reaction materials that undergo significant volume changes during cycling.

Purpose of the Study:

• To investigate the impact of tin (Sn) particle size and conductive additive type on the electrochemical performance of Sn-based electrodes for Na-ion batteries.
• To evaluate the role of carbon fibers (VGCF) as a conductive additive in buffering volume changes in Sn electrodes.

Main Methods:

• Fabrication of Sn-CMC electrodes using different Sn particle sizes (micro- and nanoparticles).
• Evaluation of electrode performance using electrochemical cycling tests.
• Analysis of the interaction between conductive additives (VGCF) and Sn particles of varying sizes.

Main Results:

• Carbon fibers (VGCF) effectively surround micrometer-sized Sn particles, improving electrode performance.
• VGCF showed less effective encapsulation of nanometer-sized Sn particles, limiting performance improvements.
• Nanoparticles exhibited limited long-term cycling performance at high active material loadings (>3.5 mg/cm(2)).

Conclusions:

• The combination of VGCF with micrometer-sized Sn particles is a promising strategy for developing high-performance electrodes for Na-ion batteries utilizing conversion reaction mechanisms.
• Optimizing electrode composition and particle morphology is crucial for overcoming challenges associated with volume expansion in conversion-based battery materials.