LAUSR

We report Layer-by-Layer (LbL) self-assembly of pillared two-dimensional (2D) multilayers, from water, onto a wide range of substrates. This LbL method uses a small molecule, tris(2-aminoethyl) amine (TAEA), and a colloidal dispersion of Ti3C2Tx MXene to LbL self-assemble (MXene/TAEA)n multilayers, where n denotes the number of bilayers. Assembly with TAEA results in highly ordered (MXene/TAEA)n multilayers where the TAEA expands the interlayer spacing of MXene flakes by only ~ 1 Å and reinforces the interconnection between them. The TAEA-pillared MXene multilayers show the highest electronic conductivity of 7.3 × 104 S m−1 compared with all reported MXene multilayers fabricated by LbL technique. The (MXene/TAEA)n multilayers could be used as electrodes for flexible all-solid-state supercapacitors delivering a high volumetric capacitance of 583 F cm−3 and high energy and power densities of 3.0 Wh L−1 and 4400 W L−1, respectively. This strategy enables large-scale fabrication of highly conductive pillared MXene multilayers, and potentially fabrication of other 2D heterostructures.Layer-by-layer self-assembly method using small molecules holds promise to precisely combine atomically thin materials and enable fabrication of pillared structures with superior device performance. Here, the authors report controlled synthesis of supercapacitor electrodes based on 2D Ti3C2Tx MXene multilayers with a volumetric capacitance of 583 F/cm3.