All-MXene-Based Integrated Membrane Electrode Constructed using Ti₃C₂T as an Intercalating Agent for High-Performance...

2D-Ti₃C₂T MXene flake restacking and the small interlayer spacing of these MXenes limit their application in capacitive deionization. Here, we designed an all-MXene-based (L-S-Ti₃C₂T) flexible film electrode, enabled by large-size Ti₃C₂T (lateral dimensions of ⩾1 μm) MXene (L-Ti₃C₂T) nanosheets, which provided conductive pathways and were active substances, and by small-size Ti₃C₂T (500 nm) MXene (S-Ti₃C₂T) nanosheets, which were used as intercalation materials and active substances, for high-performance desalination in capacitive deionization applications. The as-synthesized L-S-Ti₃C₂T electrode achieved an excellent capacitance (169 F/g at 5 mV/s) and long-term cycling stability (maintained 91.7% of the initial capacitance after 5000 cycles). Additionally, these electrodes exhibited a high electroadsorption capacity (72 mg NaCl/g L-S-Ti₃C₂T, 10 mM NaCl solution). The improved electrochemical and desalination performance and outstanding long-term cycling stability can be attributed to the small Ti₃C₂T sheets that were introduced, which could be beneficial in exposing more active sites, facilitating electron transport, and shortening the diffusion path of Na ions. Our work opens up a new design space for the development of high-performance anode materials.