Construction of mesoporous N-doped carbon-coated MXene-MoS2 heterostructured microspheres via a spray-drying method as a high capacity and long cycle-life anode for potassium-ion batteries

Heterostructured materials with 2D architecture capitalizing on the unique benefits of each component and the emergent properties from their synergy have ignited considerable interest in the field of rechargeable batteries. Nevertheless, inhibiting the restacking issue inherent to 2D materials and optimizing the structural design to enhance the electrochemical reactions continue to pose substantial challenges. In this study, we successfully fabricated porous 3D N-doped carbon microspheres consisting of MXene and molybdenum disulfide (MX/MoS2 @NC) for use as an electrode material in potassium-ion batteries via a facile spray-drying method. The MX/MoS2 @NC electrode showcased excellent electrochemical properties as an anode, delivering stable cycling performance and minimal capacity decay (350 mA h g−1 at 0.5 A g−1 after 400 cycles). It also exhibits improved rate capability and enhanced ion transport kinetics (219 mA h g−1 at 2.0 A g−1). The high performance of this composite can be traced back to its 3D microspherical structure facilitating efficient ion transport, the synergy between MXene and N-doped carbon enhancing its structural robustness and electrical conductivity, and the 2D MXene nanosheets preventing MoS2 restacking. This investigation underscores the MX/MoS2 @NC composite as a promising candidate for potassium-ion battery applications.