Pristine Titanium Carbide MXene Hydrogel Matrix

Abstract

The hydrogel matrix normally forms via covalent or noncovalent interactions that make the matrix resistant to hydration and disassembly. Herein this type of chemical transition is demonstrated in titanium carbide MXene (Ti₃C₂T_x), in which the exchange of intercalated Li⁺ with hydrated protons triggers significantly suppressed hydration in stacked Ti₃C₂T_x. Based on this intercalation chemistry behavior, pristine Ti₃C₂T_x hydrogel matrices with an arbitrary microstructures are fabricated by freezing-induced preassembly and a subsequent specially designed thawing process in protic acids. The absence of extrinsic components maximizes the materials performance of the resultant pristine Ti₃C₂T_x hydrogel, which produces a compressive modulus of 2.4 MPa and conductivity of 220.3 ± 16.8 S/m at 5 wt % solid content. The anisotropic Ti₃C₂T_x hydrogel also delivers a promising performance in solar steam generation by facilitating rapid water transport inside vertical microchannels.

Keywords: MXene; anisotropy; hydrogels; intercalation chemistry; microstructure control.