Ion-Confinement-Assisted Erasure Purifies Oxidized MXene for Reuse

Titanium carbide (Ti₃C₂T_x) MXene has attracted broad interest owing to its versatile functional properties. However, its intrinsic instability in aqueous environments drives spontaneous surface oxidation to insulating TiO₂, resulting in pronounced performance degradation and posing a major obstacle to practical utilization. Here, we propose an erasure-purification strategy that selectively targets surface-derived oxide phases on oxidized MXene. By constructing an ion-confined interfacial environment followed by a brief acid-washing step, further oxidation is mitigated while pre-existing TiO₂ is selectively removed. The recovered MXene exhibits restored colloidal stability and can be reassembled into conductive films delivering high volumetric capacitance and favorable rate performance. In addition, the purified MXene demonstrates competitive low-frequency electromagnetic attenuation and low infrared emissivity in assembled forms. This approach is applicable to MXene with different morphologies and oxidation states, offering a practical and generalizable route for reclaiming and reusing oxidized MXene materials.