Achieving Full Redispersion of Dried MXene Monoliths via Trace Metal Cation Intercalation.

MXenes, a class of 2D transition metal carbides and nitrides, exhibit exceptional electrical conductivity and solution dispersibility, making them promising materials for various applications. However, their long-term stability remains a critical challenge due to oxidation in aqueous dispersions. While the transformation of these dispersions into water-redispersible dry monoliths is highly desirable, achieving this has proven difficult. This study introduces a facile approach to enhance the redispersion yield of dried MXene monoliths by incorporating trace amounts of metal cations (Li, Mg, and Al) into aqueous dispersions prior to lyophilization. These cations intercalate between MXene sheets, acting as atomic pillars that inhibit face-to-face restacking and facilitate water infiltration during redispersion. Systematic investigations reveal that optimal cation concentrations significantly improve redispersion efficiency without inducing flocculation, achieving yields of up to 100% for Li-modified MXenes. Characterization of redispersed MXene nanosheets confirms preserved morphology and structural integrity. Furthermore, compared to the pristine MXene counterparts, MXene films made from cation-aided redispersions show higher electrical conductivity and electromagnetic interference shielding performances. This simple yet effective strategy addresses key challenges in MXene storage and processing, enabling reliable solution-based fabrication for energy storage, sensing, and electronic applications.