<p>The scalable synthesis of high-quality MXenes with minimal layer stacking remains a critical challenge for their practical applications. Here, we report a modified molten salt-assisted strategy to construct a 3D porous Ti₃C₂T_<i>x</i>@K₂Ti₈O₁₇ heterostructure, simultaneously addressing MXene restacking and enhancing electrochemical performance. By exfoliating Ti₃C₂T_<i>x</i> in a LiCl-AlCl₃ molten salt medium followed by in-situ KOH-induced transformation, K₂Ti₈O₁₇ nanoflakes are uniformly embedded between MXene layers, acting as permanent spacers to inhibit aggregation while creating a conductive, catalytic network. As a proof of concept, the engineered Ti₃C₂T_<i>x</i>@K₂Ti₈O₁₇ heterostructure is implemented as a multifunctional separator for zinc-iodine batteries (ZIBs), the optimized ZIBs demonstrates exceptional cycling stability with ultralow capacity decay (0.0008% per cycle at 50&#xa0;C over 7000 cycles) and remarkable rate capability (137.4 mAh g^− 1 at 50&#xa0;C), far outperforming commercial polypropylene separator based ZIBs. The excellent performances of the ZIBs can be attributed to the following factors: (1) iodine redox kinetics is significantly accelerated by the conductive MXene matrix, (2) polyiodide shuttle effects are suppressed through chemisorption on K₂Ti₈O₁₇ spacers, and (3) electrolyte permeability is improved by the hierarchically porous architecture. This strategy combines strong adsorption with fast electrochemical reactions, providing a simple and effective solution for optimizing the performance of Zn-I₂ batteries.</p>