Highly electrically conductive and air-stable metal chloride ternary graphite intercalation compounds with AlCl3-FeCl3 and AlCl3-CuCl2 prepared from flexible graphite sheets

•Metal chlorides ternary GICs were fabricated from PGS and GRAFOIL graphite sheets.•Electrical conductivity and air-stability of ternary GICs were investigated.•Ternary GICs have higher electrical conductivity than binary GICs.•AlCl3-CuCl2-GIC prepared from PGS is highly conductive and air-stable.

Ternary graphite intercalation compounds (GICs) incorporating two kinds of metal chlorides, namely, AlCl3-FeCl3-GIC and AlCl3-CuCl2-GIC, were synthesized from two types of graphite sheets, PGS and GRAFOIL. Their electrical conductivities and air-stabilities were evaluated in an attempt to identify highly electrically conductive and air-stable GICs. Their electrical conductivities were found to be higher than those of binary GICs such as FeCl3- and CuCl2-GICs. Especially, the AlCl3-CuCl2-GIC prepared from a PGS graphite sheet was found to have a high conductivity and high air-stability; the highest electrical conductivity was in excess of 1.0 × 105 Scm−1. Most AlCl3-CuCl2-GICs have a mixed structure of AlCl3-CuCl2-ternary GIC domains and/or AlCl3-GIC domains. The proportion of each domain was dependent on the reaction time and the type of the host graphite. AlCl3-FeCl3-GICs prepared from PGS were found to consist only of FeCl3-GICs, and their electrical conductivity and air-stability were slightly inferior to those of AlCl3-CuCl2-GICs. We concluded that an AlCl3-CuCl2-ternary GIC prepared from a PGS graphite sheet is highly electrically conductive and highly air-stable. Therefore, this is a promising candidate as a highly conductive and air-stable GIC for use in practical applications as a conducting material.