Filter, Flip, and Fabricate: A Wax-Assisted Stamp-Transfer Approach for Flexible Ti ₃ C ₂ T _<i>x</i> MXene Electrochemical Transducers

Combining additive-free solution processing of MXenes with template-assisted transfer represents an innovative approach for the fabrication of electrochemical sensors. Herein, we introduce a wax-assisted templating and stamp-transfer (<i>WAST</i>) approach to fabricate monolithic MXene transducers. To this end, two configurations were developed: (A) <i>MXene-at-all electrodes</i>, where the working, counter, and reference electrodes were entirely composed of MXene, and (B) MXene working electrodes combined with an Ag/AgCl pseudoreference and carbon counter electrodes. Additive-free MXene inks, at different concentrations and volumes, were filtered onto wax-templated PVDF membranes to form stampable patterns. Voltammetric characterization revealed consistent anodic and cathodic peak currents (<i>I</i>_pa and <i>I</i>_pc) and steady peak-to-peak separation <i>(</i>Δ<i>E</i>_p) across three independent batches, indicating excellent reproducibility with <i>I</i>_pa = 87.9 ± 1.7 μA, <i>I</i>_pc = -81.3 ± 1.5 μA, and Δ<i>E</i>_p = 255.9 ± 4.6 mV for configuration A, and <i>I</i>_pa = 43.8 ± 0.6 μA, <i>I</i>_pc <i>=</i> -62.8 ± 1.2 μA, with a 3-fold lower peak separation (Δ<i>E</i>_p = 87.6 ± 0.9 mV) in the case of configuration B (mean ± SE, <i>n</i> = 15). Primary benchmarking with similar commercial systems signifies the efficacy of <i>WAST</i>-produced transducers to mimic commercial electrode performance and provides a robust alternative to conventional deposition methods. In addition, a proof-of-concept experiment for Hg²⁺ ion sensing validated its potential for practical applications. The <i>WAST</i> method offers a robust fabrication, configuration choice, and tool-light patterning that can accelerate lab-scale prototyping of stand-alone flexible electrochemical devices.