Polyoxometalate-coupled graphene via polymeric ionic liquid linker for supercapacitors

Min Ho Yang, Bong Gill Choi, Sung Chul Jung, Young Kyu Han, Yun Suk Huh, Sang Bok Lee

Research output: Contribution to journalArticlepeer-review

115 Scopus citations

Abstract

The integration of electrical double-layer capacitive and pseudocapacitive materials into novel hybrid materials is crucial to realize supercapacitors with high energy and power densities. Here, high levels of energy and power densities are demonstrated in supercapacitors based on a new type of nanohybrid electrode consisting of polyoxometalate (POM)-coupled graphene in which a polymeric ionic liquid (henceforth simply PIL) serves as an interfacial linker. The adoption of PIL in the construction of nanohybrids enables a uniform distribution of discrete POM molecules along with a large surface area of graphene sheets. When testing electrochemical characteristics under a two-electrode system, as-prepared supercapacitors exhibit a high specifi c capacitance (408 F g -1 at 0.5 A g -1 ), rapid rate capability (92% retention at 10 A g -1 ), a long cycling life (98% retention during 2000 cycles), and high energy (56 Wh kg -1 ) and power (52 kW kg -1 ) densities. First-principles calculations and impedance spectroscopy analysis reveal that the PILs enhance the redox reactions of POMs by providing effi cient ion transfer channels and facilitating the charge transfer in the nanohybrids.

Original languageEnglish
Pages (from-to)7301-7309
Number of pages9
JournalAdvanced Functional Materials
Volume24
Issue number46
DOIs
StatePublished - 10 Dec 2014

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