Turning Trash into Treasure: Additive Free MXene Sediment Inks for Screen‐Printed Micro‐Supercapacitors

TLDR

Printed functional conductive inks enable scalable smart electronics, yet formulating additive‑free inks without costly post‑deposition treatments is difficult due to the high filler concentration required. The study introduces a waste‑free MXene sediment ink strategy that turns discarded material into a scalable, sustainable screen‑printed platform for next‑generation wearable electronics. The inks are composed of the sediments of unetched precursor and multilayered MXene, normally discarded after delamination. Screen‑printed micro‑supercapacitors on paper show high resolution, uniformity, and superior areal capacitance (158 mF cm⁻²) and energy density (1.64 µWh cm⁻²), with delaminated nanosheets serving as conductive binders that preserve mechanical integrity.

Abstract

Abstract Printed functional conductive inks have triggered scalable production of smart electronics such as energy‐storage devices, antennas, wearable electronics, etc. Of particular interest are highly conductive‐additive‐free inks devoid of costly postdeposition treatments to eliminate sacrificial components. Due to the high filler concentration required, formulation of such waste‐free inks has proven quite challenging. Here, additive‐free, 2D titanium carbide MXene aqueous inks with appropriate rheological properties for scalable screen printing are demonstrated. Importantly, the inks consist essentially of the sediments of unetched precursor and multilayered MXene, which are usually discarded after delamination. Screen‐printed structures are presented on paper with high resolution and spatial uniformity, including micro‐supercapacitors, conductive tracks, integrated circuit paths, and others. It is revealed that the delaminated nanosheets among the layered particles function as efficient conductive binders, maintaining the mechanical integrity and thus the metallic conductive network. The areal capacitance (158 mF cm −2 ) and energy density (1.64 µWh cm −2 ) of the printed micro‐supercapacitors are much superior to other devices based on MXene or graphene. The ink formulation strategy of “turning trash into treasure” for screen printing highlights the potential of waste‐free MXene sediment printing for scalable and sustainable production of next‐generation wearable smart electronics.