Electrochemical etching: towards a scalable production of MXene

Official URL: https://dx.doi.org/10.1002/admt.202501403

MXenes, a class of 2D transition metal carbides, nitrides, and carbonitrides, are gaining attention for their remarkable properties, including high electrical conductivity, large surface area, and excellent electrochemical performance. These attributes make MXenes suitable for applications in energy storage, sensors, catalysts, and electromagnetic interference shielding. However, one of the significant challenges with MXene synthesis is the use of hazardous hydrofluoric acid (HF) in the etching process, which also presents environmental concerns, thereby limiting their scalability and broader use. This has prompted significant research into alternative synthetic methods by using safer fluoride-containing salts or electrochemical etching techniques. The electrochemical etching process provides larger lateral dimensions of MXene flakes due to the controlled etching process, surpassing HF decomposition. The slow etching also leads to uniform and larger-sized MXene sheets along with relevant functional groups, which can be advantageous for certain applications. This review dives into the electrochemical etching route for preparing MXenes, elaborating on the effect of time, voltage, and electrolyte composition on the morphology, electrical conductivity, surface termination, and performance of the obtained MXenes on the target application. The potential to achieve a sustainable mass production is briefly explored to guide future research directions in this growing area.