Electrochemical and in-situ X-ray diffraction studies of Ti 3 C 2 T x MXene in ionic liquid electrolyte

Abstract

2D titanium carbide (Ti 3 C 2 T x MXene) showed good capacitance in both organic and neat ionic liquid electrolytes, but its charge storage mechanism is still not fully understood. Here, electrochemical characteristics of Ti 3 C 2 T x electrode were studied in neat EMI-TFSI electrolyte. A capacitive behavior was observed within a large electrochemical potential range (from −1.5 to 1.5 V vs. Ag). Intercalation and de-intercalation of EMI + cations and/or TFSI − anions were investigated by in-situ X-ray diffraction. Interlayer spacing of Ti 3 C 2 T x flakes decreases during positive polarization, which can be ascribed to either electrostatic attraction effect between intercalated TFSI − anions and positively charged Ti 3 C 2 T x nanosheets or steric effect caused by de-intercalation of EMI + cations.The expansion of interlayer spacing when polarized to negative potentials is explained by steric effect of cation intercalation.

Fabrication of Cobaltosic Oxide Nanoparticle‐Doped 3 D MXene/Graphene Hybrid Porous Aerogels for All‐Solid‐State Supercapacitors

“…[20] The peaks at 780.5 and 796.4 eV correspond to Co 3 + ,a nd those at 781.9 and 797.8 eV to Co 2 + . [21] Furthermore, the peaks at 786.2 and 803.2 eV can be ascribed to the shake-up satellite peaks of Co 2 + .…”

MXene-based materials for electrochemical energy storage

“…Lin et al . [158] for the first time proposed the utilization of Ti 3 C 2 T x MXene as supercapacitor electrodes in ionic liquid electrolytes (1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl) imide (EMI-TFSI)) with a large voltage window of 3 V. Subsequently, the electrochemical characters of Ti 3 C 2 T x electrodes were investigated through in situ XRD in neat EMI-TFSI electrolytes [159] . Besides, MXene was also applied to solid-state supercapacitors.…”

MXene as a novel intercalation-type pseudocapacitive cathode and anode for capacitive deionization

“…While most works in the literature have investigated cation intercalation in MXenes, 22 recent works provide experimental evidence also for anion insertion derived from in situ X-ray diffraction experiments. 33 By that virtue, MXene is an interesting model material for applying faradaic anion and cation immobilization towards pseudocapacitive desalination.…”