Ti3C2Tx MXene@carbon dots hybrid microflowers as a binder-free electrode material toward high capacity capacitive deionization

Owing to the exceptional electrical conductivity and high hydrophilic surface area, MXene is regarded as one of the most glaring capacitive deionization (CDI) electrode materials. However, the self-stacking of pure MXene nanosheets though van der Waals forces seriously hinders its electrochemical performance. Therefore, A novel pathway to prepare flexible and binder-free MXene@carbon dots (MXene@CDs) electrodes materials for CDI using electrostatic self-assembly between negatively charged Ti3C2Tx MXene and positively charged CDs is presented. The 2D MXene nanosheets are bended and formed hybrid microflowers. This unique structure can reduce the self-stacking of MXene during film formation, accelerating ion transport and increasing ion storage. The binder-free electrode MXene@CDs-2 shows an excellent deionization capacity of 86.4 mg/g in 10 mM NaCl solution. Moreover, the relativity low energy consumption (0.13 kWh/kg-NaCl) and high energy recovery (12.61 %) are achieved. This strategy of combining zero-dimensional and two-dimensional nanomaterials to form microflowers can promote the CDI performance of MXene-based materials.

Automated summary

The study presents a novel pathway to prepare flexible and binder-free MXene@carbon dots (MXene@CDs) electrodes using electrostatic self-assembly. The unique microflower structure of the MXene-based materials reduces self-stacking, improves ion transport, and enhances ion storage. The electrode exhibits excellent deionization capacity and high energy recovery.