Molecular Ligand‐Mediated Assembly of Multicomponent Nanosheet Superlattices for Compact Capacitive Energy Storage

Inspired by the self-assembly of nanoparticle superlattices, we report herein a general methodology that exploits long-chain molecular ligands to induce ordered assembly of colloidal nanosheets (NSs), resulting in 2D laminate superlattices with high packing density. Co-assembly of two types of NSs further enables 2D/2D heterostructured superlattices. As a proof of concept, co-assembly of Ti 3 C 2 T x and graphene oxide (GO) NSs followed by thermal annealing leads to MXene-rGO superlattices with tunable microstructures, which exhibit significantly higher capacitance than their filtrated counterparts, delivering an ultrahigh volumetric capacitance of 1443 F cm -3 at 2 mV S -1 . Moreover, the as-fabricated binder-free symmetric supercapacitors show a high volumetric energy density of 42.1 Wh L -1 , which is among the best ever reported for MXene-based materials in aqueous electrolytes. This work paves the way toward rational design of 2D material-based superstructures for energy applications.