▎ 摘　　要

NOVELTY - An imidazolidine-type compound (I) is new. USE - New imidazolidine-type compound is used for mixed ionic liquid for preparation of graphene dispersion liquid (all claimed) for electronic component e.g. energy storage electrical appliance and lithium-ion secondary battery. ADVANTAGE - The imidazolidine-type compound has excellent dispersibility. The graphene dispersion liquid is efficiently prepared by the imidazolidine-type compound. DETAILED DESCRIPTION - An imidazolidine-type compound of formula (I) is new. R1,R5=optionally substituted 1-7C linear or branched alkyl; R2=-(R6-O)m-R7-; R6,R7=1-4C linear or branched alkylene; m=1-5; R3,R4=H or optionally substituted 1-4C linear or branched alkyl; X-=counter ion;and n=0-30. INDEPENDENT CLAIMS are included for the following: (1) mixed ionic liquid, which comprises imidazolidine-type compound, and butyl methyl imidazolium hexafluorophosphate or butyl methyl imidazolium bis(trifluoromethanesulfonyl)imide; (2) graphene dispersion liquid, which contains graphene and imidazolidine-type compound; and (3) preparation of graphene dispersion liquid, which involves adding graphite to imidazolidine-type compound or mixed ionic liquid, obtaining liquid mixture and applying an ultrasonic wave or microwave to the obtained liquid mixture.