2D Porous Ti₃C₂ MXene as Anode Material for Sodium-Ion Batteries with Excellent Reaction Kinetics

Sodium-ion batteries (SIBs) are a promising electrochemical energy storage system but face great challenges in developing fast-charging anodes. MXene-based composites are a new class of two-dimensional materials that are expected to be widely used in SIB energy storage due to their excellent electrical conductivity and stable structure. However, MXenes tend to experience interlayer stacking during preparation, which can result in poor electrochemical performance and a lower actual capacity compared to the theoretical value. In this study, the porous structure was created using a chemical oxidation method from a microscopic perspective. The porous MXene (referred to as PM) was prepared by using a low concentration of hydrogen peroxide as the pore-forming solution, which enlarged the interlayer spacing to facilitate the transport of sodium ions in the electrolyte solution. The PM with the addition of hydrogen peroxide solution achieved high-rate performance, with a capacity of 247 mAh g^-1 at 0.1 A g^-1 and 114 mAh g^-1 at 10 A g^-1. It also demonstrated long-cycle stability, with a capacity of 117 mAh g^-1 maintained over 1000 cycles at 5 A g^-1.