Staging Phenomena in Lithium-Intercalated Boron-Carbon.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Condensed Matter Physics

Background:

• Hole-doped LiBC is a material of interest for high-temperature superconductivity and rechargeable lithium batteries due to its structural resemblance to MgB$_{2}$ and graphenelike BC hexagons.
• Limited synthesis studies have hindered comprehensive understanding of Li$_{x}$BC's structural, electronic, and application properties.

Purpose of the Study:

• To synthesize hole-doped Li$_{0.5}$BC and characterize its structural and electronic properties.
• To investigate the influence of lithium content and intralayer motion on the material's structural and electronic behavior.

Main Methods:

• Successful synthesis of hole-doped Li$_{0.5}$BC.
• Detailed structural modeling based on X-ray diffraction data, revealing a stage-2 Daumas-Hérold-type domain structure.
• Compressibility measurements on Li$_{0.85}$BC and Li$_{0.48}$BC to study structural properties.

Main Results:

• The synthesis of hole-doped Li$_{0.5}$BC was successful.
• Extraordinary structural properties, including staging and staging disorder, were observed, driven by intralayer motion of guest Li islands.
• Compressibility results indicated anisotropic behavior for Li$_{0.85}$BC (B$_{0}$ ∼ 134 GPa) and isotropic behavior for Li$_{0.48}$BC (B$_{0}$ ∼ 190 GPa).
• Li deficiency enhances conductivity, but temperature-dependent conductivity is governed by thermal excitation in a disordered regime with localized states.

Conclusions:

• The study successfully synthesized and characterized hole-doped Li$_{0.5}$BC, elucidating its unique structural and electronic properties.
• The findings highlight the significant role of lithium island dynamics and Li deficiency in influencing the material's structural integrity and electrical conductivity.
• The research provides a foundation for further exploration of Li$_{x}$BC in potential applications such as superconductivity and energy storage.