Dual‐Functional V₂C MXene Assembly in Facilitating Sulfur Evolution Kinetics and Li‐Ion Sieving toward Practical Lithium–Sulfur Batteries

Abstract Lithium–sulfur (Li–S) batteries are considered as one of the most promising candidates to achieve an energy density of 500 Wh kg⁻¹. However, the challenges of shuttle effect, sluggish sulfur conversion kinetics, and lithium‐dendrite growth severely obstruct their practical implementation. Herein, multiscale V₂C MXene (VC) with a spherical confinement structure is designed as a high‐efficiency bifunctional promotor for the evolution of sulfur and lithium species in Li–S batteries. Combining synchrotron X‐ray 3D nano‐computed tomography (X‐ray 3D nano‐CT), small‐angle neutron scattering (SANS), and first‐principle calculations, it is revealed that the activity of VC can be maximized by tuning the scale, and the as‐attained functions are conducted as follows: (i) the VC acts as the efficient lithium polysulfide (LiPS) scavenger due to the large number of active sites; (ii) the VC exhibits significantly improved electrocatalytic function for the Li₂S nucleation and decomposition reaction kinetics owing to the scale effect; and (iii) the VC can regulate the dynamic behavior of Li‐ions and thus stabilize the lithium plating/stripping effectively on account of the unique ion‐sieving effect.