Hydrogen-Bond Restructuring of Water-in-Salt Electrolyte Confined in Ti3C2Tx MXene Monitored by Operando Infrared Spectroscopy.
J Phys Chem Lett
; 14(6): 1578-1584, 2023 Feb 16.
Article
in En
| MEDLINE
| ID: mdl-36748744
ABSTRACT
Highly concentrated water-in-salt aqueous electrolytes exhibit a wider potential window compared to conventional, dilute aqueous electrolytes. Coupled with MXenes, a family of two-dimensional transition metal carbides and nitrides with impressive charge storage capabilities, water-in-salt electrolytes present a potential candidate to replace flammable and toxic organic solvents in electrochemical energy storage devices. A new charge storage mechanism was recently discovered during electrochemical cycling of Ti3C2Tx MXene electrodes in lithium-based water-in-salt electrolytes, attributed to intercalation and deintercalation of solvated Li+ ions at anodic potentials. Nevertheless, direct evidence of the state of Li+ solvation during cycling is still missing. Here, we investigate the hydrogen bonding of water intercalated between MXene layers during electrochemical cycling in a water-in-salt electrolyte with operando infrared spectroscopy. The hydrogen-bonding state of the confined water was found to change significantly as a function of potential and the concentration of Li+ ions in the interlayer space. This study provides fundamentally new insights into the electrolyte structural changes while intercalating Li+ in the MXene interlayer space.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Chem Lett
Year:
2023
Document type:
Article
Affiliation country:
Germany