Direct synthesis and chemical vapor deposition of 2D carbide and nitride MXenes

TL;DR

This paper introduces a scalable, direct chemical vapor deposition method for synthesizing 2D MXenes, including new phases, with high energy storage capacity and complex morphologies, bypassing traditional MAX phase etching.

Contribution

It presents a novel direct synthesis route for MXenes, enabling scalable production and new phases, with applications in energy storage and complex nanostructure formation.

Findings

Direct synthesis of MXenes achieved without MAX phases

MXenes exhibit high energy storage capacity for Li-ion intercalation

CVD growth produces complex morphologies like spherulite-like structures

Abstract

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) are a large family of materials actively studied for various applications, especially in the field of energy storage. To date, MXenes are commonly synthesized by etching the layered ternary compounds, MAX phases. Here we demonstrate a direct synthetic route for scalable and atom-economic synthesis of MXenes, including phases that have not been synthesized from MAX phases, by the reactions of metals and metal halides with graphite, methane or nitrogen. These directly synthesized MXenes showed excellent energy storage capacity for Li-ion intercalation. The direct synthesis enables chemical vapor deposition (CVD) growth of MXene carpets and complex spherulite-like morphologies. The latter form in a process resembling the evolution of cellular membranes during endocytosis.