A green and scalable electrochemical route for cost-effective mass production of MXenes

17 August 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

One of the most unique properties of two-dimensional carbides and nitrides of transition metals (MXenes) is their excellent water dispersibility and yet possessing superior electrical conductivity but their industrial-scale application is limited by their costly chemical synthesis methods. In this work, the niche feature of MXene was capitalized in the packed-bed electrochemical reactor (PBER) to produce MXene at an unprecedented reaction rate and yield with minimal chemical waste. A simple NH4F solution was employed as the green electrolyte which could be used repeatedly without any loss in its efficacy. Surprisingly, both fluoride and ammonium were found to play critical roles in the electrochemical etching, functionalization, and expansion of the layered parent materials (MAXs) through which the liberation of ammonia gas was observed. The electrochemically produced MXenes (eMXenes) with excellent conductivity, applied as supercapacitor electrodes, could deliver an ultra-high volumetric capacity (1408 F cm-3) and volumetric energy density (75.8 Wh L-1). This revolutionary green, energy efficient and scalable electrochemical route will not only pave the way for industrial-scale production of MXene but also open up a myriad of versatile electrochemical modifications for improved functional MXenes.

Keywords

MXene
Electrochemical Etching
Packed-bed Electrochemical Reactor
Green
Cost-Effective
Scalable

Supplementary materials

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Description
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Video S1
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pH testing of evolved gas with wetted pH indicator strips from divided MAX anode and Pt cathode compartment
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Supporting Information
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Supporting data and results
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