Rod-Like LiBC Anode with High Specific Capacity in Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Lithium borocarbide (LiBC) is a graphite-like material known for superconductivity.
• LiBC also shows potential as an electrode material in lithium-ion batteries due to its high specific capacity, attributed to B-B bonds.
• Existing synthesis methods may not fully optimize the formation of these beneficial B-B bonds.

Purpose of the Study:

• To synthesize a novel rod-like lithium borocarbide (Ti-LiBC) material.
• To investigate the effect of synthesis atmosphere and precursors on LiBC morphology and electrochemical properties.
• To enhance the specific capacity and performance of LiBC as a lithium-ion battery electrode.

Main Methods:

• High-temperature sintering of lithium hydride (LiH), boron (B), and graphite precursors within a sealed titanium (Ti) tube.
• Comparative synthesis using a SUS304 stainless steel tube (SUS-LiBC).
• Electrochemical characterization including specific capacity, rate capability, and cycle performance testing.

Main Results:

• The synthesized Ti-LiBC exhibited a rod-like morphology with abundant B-B bonds and a strong Electron Paramagnetic Resonance (EPR) signal.
• Ti-LiBC delivered a significantly higher specific capacity (approx. 500 mAh g⁻¹) compared to SUS-LiBC.
• Excellent rate and cycle performances were observed for the Ti-LiBC electrode material.

Conclusions:

• A hydrogen-free atmosphere is crucial for synthesizing rod-like LiBC with optimal electrochemical properties.
• The use of Ti metal and LiH precursor, under specific conditions, promotes the formation of B-B bonds and rod-like structures.
• This synthesis strategy offers a pathway for improving graphite-like materials for energy storage applications.