Fluoride-free synthesis and microstructure evolution of novel two-dimensional Ti3C2(OH)2 nanoribbons as high-performance anode materials for lithium-ion batteries

Abstract

Herein, we develop a fluoride-free hydrothermal etching approach using the small amounts of water-assisted potassium hydroxide as ingenious etching agents to produce novel two-dimensional Ti3C2(OH)2-MXene nanoribbons (Ti3C2(OH)2 NRs). The as-produced Ti3C2(OH)2 NRs possess less Al atoms, more abundant hydroxyl functional groups on their surface, and more open structure features compared with their pristine counterparts and the other etching products. Simultaneously, the resulting Ti3C2(OH)2 NRs show significantly enhanced Li ions storage capabilities with outstanding specific capacity of 143.4 mA h g−1 obtained at 100 mA g−1 after 250 cycles, excellent cycling stability, and good rate property, being significantly superior than the parent Ti3AlC2 phases and the sugarcane-like transitional etching products. The superior electrochemical properties of Ti3C2(OH)2 NRs could be ascribed to the unique nanoribbon architectures with rich hydroxyl terminal groups and few Al atoms, which facilitates the adsorption and storage of a growing number of Li ions on the surface active sites of Ti3C2(OH)2 NRs and the transport of electrons and ions effectively. What's more, this study provides a simple, effective, green, and nontoxic fluoride-free etching procedure to synthesize other more MXenes nanoribbons including but not limited to Ti3C2(OH)2 NRs as promising anode candidates for advanced lithium-ion batteries.