Life-Cycle Assessment of Ti3C2Tx MXene Synthesis

Abstract

MXenes, 2D transition metal carbides, nitrides, and carbonitrides, have been investigated for diverse applications since their discovery; however, their life-cycle assessment (LCA) has not been studied. Here, a “cradle to gate” LCA is performed to assess the cumulative energy demand (CED) and environmental impacts of lab-scale synthesis of Ti3C2Tx, the most researched MXene composition. Electromagnetic interface (EMI) shielding is selected as it is one of MXenes' most promising applications and LCA of Ti3C2Tx synthesis is compared to aluminum and copper foils, two typical EMI-shielding materials. Two laboratory-scale MXene synthesis systems—gram and kilogram batches—are examined. The CED and environmental implications of Ti3C2Tx synthesis are investigated based on its precursor production, selective etching, delamination processes, laboratory location, energy mix, and raw material type. These results show that laboratory electricity usage for the synthesis processes accounts for >70% of the environmental impacts. Manufacturing 1.0 kg of industrial-scale aluminum and copper foil releases 23.0 kg and 8.75 kg of CO2, respectively, while 1.0 kg of lab-scale MXene synthesis releases 428.10 kg. Chemical usage is less impactful than electricity, which suggests that recycled resources and renewable energy can make MXene synthesis more sustainable. Understanding MXene LCA helps the industrialization of this material.