Rational design of conductive MXenes-based networks by Sn and Sn₄P₃ nanoparticles for durable sodium-ion battery

MXene has been recognized as a promising anode for sodium-ion batteries (SIBs) owing to its high electrical conductivity and long-term durability. But the low energy density and agglomeration-prone nature extensively preclude their application similar to that of other two-dimensional (2D) materials. This work transformed 2D MXene to a three-dimensional (3D) conductive network by incorporating Sn and Sn4P3 nanoparticles between the MXene sheets. The homogenous distribution of ultrasmall Sn nanoparticles (similar to 4 nm) ensures a highly conductive network not only along the MXene planes but also perpendicular to them, while the covalent-bonded Sn4P3 nanoparticles significantly reinforce the structural stability. Additionally, in/ex situ characterizations reveal a considerably high reversibility of the Na+ insertion/extraction process in the network. Benefiting from the rational design, the 3D conductive network yields an enhanced capacity, long-term cycling stability (127.2 mAh g(-1) after 1000 cycles at 5 A g(-1)), and superior pseudocapacitive properties.