Engineering MnS Cathodes via Full-Voltage H+/Zn2+ Coinsertion and Synergistic Carbon Dot Regulation for Zinc-Ion Storage

Manganese sulfide (MnS) is regarded as an ideal cathode for zinc-based energy storage devices. Nevertheless, its practical application is constrained by an underutilized theoretical capacity, slow reaction kinetics, deficient structural stability, and unclear energy storage mechanisms. Inspired by density functional theory (DFT) calculations and d-band center theory, a synergistic modification strategy of vacancy/heterojunction engineering and size regulation is employed to synthesize vacancy-rich and heterostructured MnS/carbon dots (CDs) hollow microspheres through a multifunctional CDs-regulated liquid sulfur template method. Interestingly, an energy storage mechanism of continuous synchronous coinsertion/extraction of H⁺/Zn²⁺ across the full voltage range is proposed. The coupling of the multifunctional CDs-regulated modification strategy and the H⁺/Zn²⁺ coinsertion mechanism enables the MnS/CDs cathode for high-performance zinc-ion batteries/capacitors (ZIBs/ZICs). Specifically, the as-constructed MnS/CDs//Zn ZIBs achieve ultrahigh specific capacity (478.2 mAh g^-1 at 0.1 A g^-1), excellent rate property (145.1 mAh g^-1 at 5 A g^-1), and ultralong cyclic life (up to 10,000 cycles). More encouragingly, the as-fabricated MnS/CDs//porous carbon (PC) ZICs deliver ultrahigh energy density (153.9 Wh kg^-1), splendid power density (10.7 kW kg^-1), and ultralong cyclic life (up to 50,000 cycles). This study provides scientific insights and guidance for comprehending the energy storage mechanisms of MnS and advancing the exploitation of high-performance zinc-based energy storage devices.