Some embodiments include a method of producing metal diboride nanomaterials having thickness down to the atomic scale and lateral areas from 10 nm to over 1 μm by preparing a mixture of a metal diboride and a suspending solution. The suspending solution can be an organic solvent or a solution containing water, and optionally can include a dispersion agent, such as a surfactant, a polymer, small molecule, or biopolymer. Further, the method includes exfoliating the metal diboride by exposing the mixture to ultrasonic energy, centrifuging the mixture forming supernatant that includes a dispersion of exfoliated metal diborides, and extracting the dispersion from the supernatant. Some embodiments include extracting the supernatant and casting the solution by diluting the dispersion with a second suspending solution that includes dissolved polymer. This can result in a composite film includes a dispersion of the exfoliated metal diborides and provides improved mechanical properties.