2025 AIChE Annual Meeting

(720d) Characteristics of Titanium Nitride Mxene in Lithium-Ion Energy Storage

Authors

Abdoulaye Djire, Texas A&M University
Mark Barteau, Texas A&M University
The continued rise in renewable energy demand requires innovation of energy storage devices. The ideal device must have high energy and power densities. The intercalation of cations in 2D materials, such as MXenes, shows promise in meeting both requirements. We recently demonstrated hydronium intercalation into a Ti4N3Tx MXene in 1M H2SO4 that resulted in high capacitance in excess of 600 F g-1 at 2 mV s-1. Since this was performed in aqueous electrolyte, the resulting energy density was limited by the small voltage window provided by water. Here, we hypothesize that the same intercalation mechanism can occur in non-aqueous electrolytes, but with much larger voltage window that enables higher energy density. To this end, we have investigated a non-aqueous electrolyte lithium hexafluorophosphate (LiPF6) using the Ti4N3Tx electrode. Specifically, we used 1M LiPF6 in 1:1 volume dimethyl carbonate and ethylene carbonate to further understand the intercalation chemistry of the Li ions. In this electrolyte, cyclic voltammetry (CV) experiments performed on the electrode displayed a wider voltage window relative to aqueous systems, reaching 2 V, while maintaining the intercalation chemistry. Galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) experiments were performed to gain further information on the capacity, energy density, and cell characteristics. Furthermore, the precursor Ti4AlN3 and derivative delaminated Ti4N3Tx, were studied. This helped demonstrate how accessible termination groups impact the charge storage mechanism. In summary, MXenes, especially nitrides, could play a significant role in electrochemical charge storage, but further studies are needed to understand the mechanism of these novel materials.