LiCl-KCl eutectic molten salt as an original and efficient medium to intercalate metals into graphite: Case of europium

Abstract

We present the successful intercalation of europium into graphite by using an original method based on LiCl-KCl molten salts mixture. After solubilization of europium in the liquid chlorides mixture at 450 °C, reactivity toward graphite is investigated. We evidence the formation of the first stage EuC6 Graphite Intercalation Compound (GIC) with a repeat distance Ic = 487 pm.Using 00l X-ray diffraction and ion beam analysis, we show that europium is intercalated into the bulk with remarkable degree of homogeneity. This is also confirmed by magnetic measurements that clearly put in evidence the antiferromagnetic transition at about TN = 40 K.Below such temperature the characteristic step-like behavior of metamagnetic transitions was found by isothermal magnetization measurements, that is generally visible only in highly pure samples.

Original synthesis route of bulk binary superconducting graphite intercalation compounds with strontium, barium and ytterbium

“…Later, fully intercalated Eu-GIC has been synthesized. 19,23 Several tries were made to obtain a bulk YbC6 intercalation compound, however attempts reported in the literature remained unsuccessful. 16 Varying experimental parameters, ytterbium intercalation has been performed using the molten salt method.…”

“…By this way, europium was successfully intercalated leading to a remarkably homogeneous bulk EuC6 GIC. 23 The present paper deals with the intercalation of three other divalent metals (Sr, Ba and Yb) using this new method in order to synthesize pure bulk corresponding binary MC6 allowing future accurate studies of their superconductivity.…”

Crystal structure of first stage strontium-graphite intercalation compound

“…Recently, the use of a solid-liquid method derived from the latter lead to the achievement of producing a fully intercalated first stage EuC 6 GIC [11]. As a matter of fact, native lithium immediately intercalates into graphite and is then progressively substituted with europium up to formation of the wanted EuC 6 compound [12].…”

Topotactic Mechanisms Related to the Graphene Planes: Chemical Intercalation of Electron Donors into Graphite

“…A graphite platelet is plunged in the molten eutectic containing dissolved europium. The final reaction product is the first stage EuC 6 compound for which all the graphitic intervals are occupied by mono‐atomic europium layers . The intercalation of europium occurs by a three steps mechanism.…”