Dense Charge Accumulation in MXene with a Hydrate-Melt Electrolyte

Kijae Kim, Yasunobu Ando, Akira Sugahara, Seongjae Ko, Yuki Yamada, Minoru Otani, Masashi Okubo, Atsuo Yamada

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

Electrochemical double-layer (EDL) capacitors operating at high charge/discharge rates are an important class of electrochemical energy storage devices. Aqueous EDL capacitors show great potential for use as inexpensive devices with much higher power; however, their energy density is severely limited by the narrow electrochemical window of water (1.23 V) and the small specific capacity of the electrodes. Here, we develop a high-voltage aqueous supercapacitor based on a highly concentrated Li+ aqueous electrolyte (hydrate melt) and a two-dimensional titanium carbide MXene electrode. Experimental and theoretical analyses reveal the existence of dense hydrated Li+ in the interlayer space of the deeply charged MXene, which is realized by the wide electrochemical window of a hydrate-melt electrolyte. The hydrate-melt electrolyte together with the large-capacitance MXene Ti2CTx improves the performance of an aqueous lithium-ion supercapacitor, offering a promising strategy for advanced aqueous capacitors.

Original languageEnglish
Pages (from-to)5190-5196
Number of pages7
JournalChemistry of Materials
Volume31
Issue number14
DOIs
Publication statusPublished - 2019 Jul 23
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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