1-aza-15-crown-5 functionalized graphene oxide for 2D graphene-based Li⁺-ion conductor

Abstract

Attachment of Li⁺ ion on graphene surface to realize Li⁺-ion conductor is a real challenge because of the weak interaction between the ions and the functional groups of graphene oxide; although, a large number of theoretical results are already available in the literature. To overcome this problem, graphene oxide is functionalized by 1-aza-15-crown-5, the cage-like structure containing four oxygens that can bind Li⁺ ion through electrostatic interaction. Li⁺ migration on graphene surface has been investigated using ac relaxation mechanism. Perfect Debye-type relaxation behavior with β (relaxation exponent) value ≈1 resulting from single ion is observed. The activation energy of Li⁺ migration arising due to cation-π interaction is found to be 0.37 eV, which agrees well with recently reported theoretical value. It is believed that this study will help to design isolated ion conductors for Li⁺-ion battery.