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Hybrid capacitors should ideally exhibit high volumetric energy density, favorable lowtemperature performance and safe operation. Here we describe a negative electrode comprising an intercalated metal-organic framework, 4,4′-biphenyl dicarboxylate dilithium [4,4′-Bph(COOLi) 2 ], which forms a repeating organic-inorganic layered structure of π-stacked biphenyl and tetrahedral LiO 4 units. The electrode shows a stepwise two-electron transfer and has a capacity of 190 mAh g −1 at 0.7 V vs. Li/Li + , which can suppress the lithium metal deposition reaction occurring an internal short circuit. A hybrid capacitor containing 4,4′-Bph(COOLi) 2 negative and activated carbon positive electrodes possesses high volumetric energy density of approximately 60 Wh L −1 and good high-rate performance, particularly at the low temperature of 0°C, because of low charge-transfer resistance along with low activation energy. Hopping mobility calculations suggest the observed low resistance properties are the result of high electron mobility arising from two electron-hopping pathways between adjacent molecules in the π-stacked biphenyl packing layer by lithium intercalation.

We demonstrate an extremely thick iMOF electrode prepared by self-assembly of the active material and conductive nanocarbon with an amphiphilic polymer, which possessed efficient electron and Li+transport and therefore exhibited an outstanding area capacity of over 2.5 mA h cm−2for high volumetric energy asymmetric capacitors.

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