Phase-inversion constructed Mo2C@NC microreactor with optimized pyridinic N p-band center for high-performance Li-S batteries.

Nitrogen-doped carbon (NC) is widely employed as a conductive matrix in Li-S batteries, yet its intrinsic catalytic contribution is often overlooked when combined with metal compounds. Herein, we propose a hierarchical microreactor architecture that integrates conductive and catalytic functions through an intimately coupled Mo2C@NC interface. Density functional theory calculations demonstrate that coupling NC with Mo2C induces pronounced electron redistribution of N atoms, with pyridinic N exhibiting the strongest charge transfer from Mo2C, making the p-band center closest to the Fermi level, thereby endowing superior LiPSs adsorption activity. Guided by this insight, a phase-inversion strategy is employed using pyridinic-N-rich polyacrylonitrile (PAN) and MoO3 precursors to construct a cross-linked MoO3@PAN network, which is subsequently transformed into Mo2C@NC microreactors after carbonization. In this structure, Mo2C nanowires are uniformly confined within pyridinic-N-rich carbon shells, forming a zero-distance conductive-catalytic interface that enables efficient electron transfer from Mo2C to NC. This integrated microreactor provides continuous electron pathways, abundant catalytic sites, and unobstructed ion transport, effectively avoiding pore blockage commonly encountered in conventional composite cathodes. Consequently, the Mo2C@NC cathode exhibits high cycling stability over 1000 cycles at 2.0 C with a low decay rate of 0.052% per cycle. Even at 4.0 C, it retains 790.6 mAh g-1 for over 400 cycles with only 0.027% fading per cycle.