Layer-by-layer self-assembly of pillared two-dimensional multilayers

Abstract 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 Ti 3 C 2 T x 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 × 10 4 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.