Dicationic ionic liquids have been attracting attention due to their high thermal storage density, which is attributed to an increase in the number of cations. However, there is no information about the effect that the dianionic structure has on the thermophysical properties of dicationic ionic liquids. Thus in this study, imidazolium-based dicationic dicarboxylate ionic liquids (C_n (MIM)₂[C_m (CO₂)₂], n = 4, 6, 8 or 10 and m = 0,1,2,3,4,5) were synthesized and their thermal properties were determined. The results showed that the dicarboxylate's spacer length has no effect on the melting point; however, a trend in which the heat of fusion of ionic liquids increases with the increase in the spacer chain length of the dication and dianions was observed. Moreover, dicationic dicarboxylate ionic liquids have a greater heat capacity than monocationic ionic liquids, but a smaller heat capacity than analogous dicationic ionic liquids with bromine. Our results also showed that the anion has a strong effect on the heat capacity of dicationic ionic liquids. In terms of thermal storage, [C₆ (MIM)₂][C₂] and [C₆ (MIM)₂][C₅] were the most promising ionic liquids, because they have thermal storage higher than monocationic ILs and mineral oil and compared with analogues ILs with bromine, they are potentially less toxic. All of the ionic liquids were soluble in protic polar solvents and DMSO, and were insoluble in aprotic and nonpolar–polar solvents. The study and determination of these properties is extremely important for future applications.

阳离子阳离子液体由于其高的储热密度而引起了人们的关注，这归因于阳离子数量的增加。但是，没有关于双阴离子结构对阳离子型离子液体的热物理性质的影响的信息。因此，在这项研究中，咪唑基二羧酸二羧酸盐离子液体（C _n（MIM）₂ [C _m（CO ₂）₂ ]，n 合成4、6、8或10，m ＝ 0、1、2、3、4、5），并确定它们的热性能。结果表明，二羧酸根的间隔长度对熔点没有影响。然而，观察到一种趋势，其中离子液体的熔融热随着指示剂和二价阴离子的间隔链长度的增加而增加。而且，二羧酸二羧酸盐离子液体具有比单阳离子离子液体更大的热容量，但是比具有溴的类似二羧酸离子液体具有更小的热容量。我们的结果还表明，阴离子对阳离子型离子液体的热容量有很强的影响。在蓄热方面，[C ₆（MIM）₂ ] [C ₂ ]和[C ₆（MIM）₂] [C ₅ ]是最有前途的离子液体，因为它们的蓄热性高于单阳离子ILs和矿物油，并且与含溴的类似物ILs相比，它们的毒性可能较小。所有的离子液体都可溶于质子极性溶剂和DMSO，不溶于质子惰性和非极性溶剂。这些特性的研究和确定对于将来的应用极为重要。