Improved Alkali Intercalation of Carbonaceous Materials in Ammonia Solution

Abstract

Alkali‐intercalated graphite compounds represent a compelling modification of carbon with significant application potential and various fundamentally important phases. The intercalation of graphite with alkali atoms (Li and K) using liquid ammonia solution as a mediating agent is reported. Alkali atoms dissolve well in liquid ammonia, which simplifies and speeds up the intercalation process, and it also avoids the high temperature formation of alkali carbides. Optical microscopy, Raman, and electron spin‐resonance spectroscopy attest that the prepared samples are highly and homogeneously intercalated to a level approaching stage‐I intercalation compounds. The method and the synthesis route may serve as a starting point for the various forms of alkali‐atom‐intercalated carbon compounds (including carbon nanotubes and graphene), which can be exploited in energy storage and further chemical modifications.

Ultralong spin lifetime in light alkali atom doped graphene

“…We optimized the procedure to yield a material with no traces of amides. 98 We emphasize at this point that while we refer to the material as "Na doped FLG", Na dopes exclusively the monolayer graphene content inside the sample.…”

Intercalation as a versatile tool for fabrication, property tuning, and phase transitions in 2D materials

“…This method does not generate electric currents as a result of intercalation; thus, liquid phase intercalation should not be confused with some electrochemical intercalation methods which involve a liquid electrolyte. The liquid source for intercalants could either be a solution containing intercalants 17,46,47 or the molten state of the intercalants itself 19,48 . The intercalation process in the liquid phase is governed by the kinetic and thermodynamic nature of the liquid-intercalant source and host.…”

“…The metal ion moves freely in the medium and eventually creeps into the layers of the host material. After the intercalation, the ejected electron is donated back from ammonia and attaches to the intercalated compound resulting in zerovalent intercalation of metals 46 . The color of the metal-ammonia solution changes from dark blue to yellowishbrown when the metal concentration is changing from low to high, which can be used as an indicator for the progress of intercalation.…”

“…Liquid ammonia and some organic solvents like methylammonium and tetrahydrofuran are known to dissolve alkali and alkaliearth metals 46 . As a result, especially liquid ammonia has been widely used to intercalate alkali and alkali-earth metals into , and black phosphorous (BP) 60 .…”

Development of a home-made experimental set-up for in situ coupling under vacuum of conductivity measurements, x-ray absorption and Raman Spectroscopies on bundles of single-walled carbon nanotubes intercalated with alkali metals

“…To overcome this two issues, many studies dealing with alkali metal intercalation into nanotubes [7][8][9][10][11][12][13][14][15][16] and even graphene [10,[17][18][19][20] have been reported. Alkali metal intercalation (also called doping in the following) leads to a significant decrease of the resistivity [5,12,21,22] together with an electronic density of states modification, evidenced by optical absorption.…”