Accelerated Lanthanide Intercalation into Graphite Catalyzed by Na

TL;DR

This paper presents a Na-catalyzed method for rapidly synthesizing lanthanide-intercalated graphite ($Ln$C$_6$), enabling efficient production with potential applications in superconductors and batteries.

Contribution

The study introduces a novel Na-catalyzed synthesis process for $Ln$C$_6$, significantly accelerating intercalation into graphite compared to traditional methods.

Findings

Successful synthesis of $Ln$C$_6$ with high yield

Formation of NaC$_x$ intermediate facilitates the process

Pellets exhibit low residual Na and are suitable for characterization

Abstract

Lanthanides ($Ln$) are notoriously difficult to intercalate into graphite. We investigated the possibility of using Na to catalyze the formation of $Ln$-intercalated graphite and successfully synthesized $Ln$C$_6$ ($Ln$ = Sm, Eu, and Yb) significantly rapidly in high yields. The synthesis process involves the formation of the reaction intermediate NaC$_x$, through the mixing of Na and C, which subsequently reacts with $Ln$ upon heating to form $Ln$C$_6$. Well-sintered $Ln$C$_6$ pellets with low residual Na concentrations ($Ln$:Na = 98:2) were fabricated by the two-step method. The pellets enabled the evaluation of $Ln$C$_6$ by powder X-ray diffraction and electrical resistivity measurements. This study highlights the versatility of the Na-catalyzed method and lays the foundation for the rapid mass production of $Ln$C$_6$, with potential applications in superconducting and rechargeable battery materials.