Universal in Situ Crafted MOx-MXene Heterostructures as Heavy and Multifunctional Hosts for 3D-Printed Li–S Batteries

The Li-S battery has emerged as a promising next-generation system for advanced energy storage. Notwithstanding the recent progress, the problematic polysulfide shuttling, retarded sulfur redox, and low output of volumetric capacity remain daunting challenges toward its practicability. In response, this work demonstrates herein a universal approach to in situ craft MO_x-MXene (M: Ti, V, and Nb) heterostructures as heavy and multifunctional hosts to harvest good battery performances with synchronous polysulfide immobilization and conversion. Theoretical calculations indicate that the in situ implanted oxides boost the reaction kinetics of polysulfide transformation without affecting the intrinsic conductivity of MXene. As a result, the representative VO_x-V₂C/S electrode enables a high volumetric capacity (offering 1645.98 mAh cm^-3 at 0.2 C) and cycling stability (retaining 631.17 mAh cm^-3 after 1500 cycles at 2.0 C with a capacity decay of 0.03% per cycle). More encouragingly, 3D-printed sulfur electrodes harnessing VO_x-V₂C hosts readily harvest an areal capacity of 9.74 mAh cm^-2 at 0.05 C under an elevated sulfur loading of 10.78 mg cm^-2, holding promise for the development of practically viable Li-S batteries.