Metal Ion-Induced Assembly of MXene Aerogels via Biomimetic Microtextures for Electromagnetic Interference Shielding, Capacitive Deionization, and Microsupercapacitors

Scaling the synergistic properties of MXene nanosheets to microporous aerogel architectures requires effective strategies to overcome the nanosheet restacking without compromising MXene's advantageous properties. Traditional assembly approaches of 3D MXene aerogels normally involve external binders/templates and/or additional functionalization, which sacrifice the electrical conductivities and electrochemical activities of MXene aerogels. Herein, inspired by the hierarchal scale textures of Phrynosoma cornutum, a crumple-textured Ti₃C₂T_x MXene platform is engineered to facilitate Mg²⁺-induced assembly, enabling conformal formation of large-area Mg²⁺-MXene aerogels without polymeric binders. Through a doctor blading technique and freeze drying, the Mg²⁺-MXene aerogels are produced with customized shapes/dimensions, featuring high surface area (140.5 m² g⁻¹), superior electrical conductivity (758.4 S m⁻¹), and high robustness in water. The highly conductive MXene aerogels show their versatile applications from macroscale technologies (e.g., electromagnetic interference shielding and capacitive deionization (CDI)) to on-chip electronics (e.g., quasi-solid-state microsupercapacitors (QMSCs)). As CDI electrodes, the Mg²⁺-MXene aerogels exhibit high salt adsorption capacity (33.3 mg g⁻¹) and long-term operation reliability (over 30 cycles), showing a superb comparison with the literature. Also, the QMSCs with interdigitated Mg²⁺-MXene aerogel electrodes demonstrate high areal capacitances (409.3 mF cm⁻²) with superior power density and energy density compared with other state-of-art QMSCs.