Construction of interlayer-structured MnS@MXene cathode via a electrostatic anchoring combined with confined...

MnS materials have gained prominence as a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to their exceptional electrical conductivity and superior electrochemical reactivity, but their practical applications are limited by the suboptimal reaction kinetics, inadequate cycle durability, as well as the ambiguities in the fundamental charge storage mechanisms. Herein, a unique interlayer-structured MnS@MXene cathode is designed and synthesized through an electrostatic anchoring combined with confined sulfidation approach, which enables in situ growth of MnS in MXene matrices, overcoming the challenges of weak interfacial bonding and uneven particle distribution encountered in traditional composite fabrication methods. The periodic stacking of MnS nanoparticles and MXene lamellae forms a large number of heterogeneous interfaces, which construct a good conductive network while offering an increased number of active sites for electrochemical reactions. When employed as a cathode material for AZIBs, the electrochemical activity of MnS is unlocked by the initial charging process, and it exhibits considerable capacity of 325 mAh g^-1 at a current density of 0.2 A g^-1 and superior cycling performance with a specific discharge capacity of 274 mAh g^-1 even after 400 cycles at a current density of 0.5 A g^-1. Even at a high current density of 2 A g^-1, a reversible specific capacity of 105 mA g^-1 is still achieved after 2500 cycles. The superior performance originates from the synergistic effect between the high electrical conductivity of MXene and the nanoscale dimension of MnS, which facilitates the electrochemical activation process of MnS involving a reversible conversion between MnOOH/ZnMn₂O₄ and Mn₂O₃/ZnMnO₃ accompanied by the co-insertion/extraction of H⁺ and Zn²⁺.