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3D ternary MX/CNT@MoSe 2 microspheres comprising MXene, MoSe 2 , and carbon nanotube were successfully synthesized via a facile spray-drying process and subsequent thermal treatment. This 3D porous structure effectively suppressed the volume expansion of the active material and enhanced the electron/ion transportation, resulting in an electrode with greater structural robustness and electrical conductivity. When employed as an anode for potassium-ion battery, the 3D ternary MX/CNT@MoSe 2 microspheres produce a superior K+ storage performance in terms of cycling stability and capacity. We believe that the facile method proposed in this study provides the foundation for the future practical use of 3D MXene-based composites in energy-storage applications. [Display omitted] • p-MX/CNT@MoSe 2 microsphere was successfully synthesized by spray drying method. • 3D structuring of MXene nanosheets effectively inhibited their restacking issue. • p-MX/CNT@MoSe 2 electrode showed excellent cycling performance in K-ion storage. • p-MX/CNT@MoSe 2 delivered a capacity of 272 mA h g−1 after 600 cycles at 0.5 A/g. • p-MX/CNT@MoSe 2 delivered a superior rate capacity at a 2.0 A g−1 high current density. This study presents a novel spray-drying method for fabricating three-dimensional (3D) porous composite microspheres (p-MX/CNT@MoSe 2) as anodes for potassium-ion batteries (KIBs). These microspheres exhibited a well-defined porous structure formed by decomposition of latex beads and consisted of uniform MoSe 2 sheets on a conductive MXene substrate and carbon nanotube (CNT) backbone. The precursor microspheres were synthesized from an aqueous solution containing MXene nanosheets, CNTs, latex beads, and molybdenum salts via spray-drying. The microspheres were homogeneously integrated into a 3D structure, establishing strong interactions. Single-step heat treatment under an inert atmosphere decomposed the latex beads, generating numerous pores, enhancing electrolyte permeation, and facilitating potassium-ion transport. The close MXene-CNT association enhanced the electronic conductivity and mitigated MoSe 2 volume fluctuations during cycling. This architecture offers exceptional benefits, including efficient ion and electron transport, reduced potassium-ion diffusion distances, and excellent tolerance to volume changes. Electrochemical tests revealed the remarkable electrochemical performance of p-MX/CNT@MoSe 2 , with a specific capacity of 272 mA h g−1 at 0.5 A/g after 600 cycles and an outstanding rate capability, providing 225 mA h g−1 at a high 2.0 A/g current density. This study highlights the importance of rational design and synthesis for advancing next-generation electrode materials and sustainable energy storage solutions. [ABSTRACT FROM AUTHOR]

Summary: Sodium‐ion batteries (SIBs) and potassium‐ion batteries (KIBs) have received much attention as next‐generation energy storage systems owing to the abundance. Nevertheless, they face great challenges in the design of optimum electrode materials for practical applications. Herein, we prepared a unique two‐dimensional structured composite consisting of N‐doped carbon‐coated CoSe2 nanocrystals and MXene nanosheets (CoSe2@NC/MX) for efficient electrochemical Na‐ and K‐ion storage. In this strategy, a Co‐based zeolitic imidazole framework (ZIF‐67) was deposited on the surface of MXene nanosheets, and the subsequent selenization process resulted in the transformation of the ZIF‐67 into CoSe2@NCs. The unique structure can shorten the transport pathways for electrons/ions and provide sufficient space to accommodate the volume change of the active materials. Furthermore, the N‐doped carbon matrix and MXene can enhance the robustness of the electrode materials. Accordingly, the composites exhibited enhanced electrochemical performance in terms of cycle stability (317 mA h g−1 after 200 cycles at 0.5 A g−1) and rate capability (343 mA h g−1 at 7.0 A g−1) for SIBs. For KIBs, they exhibited a high reversible capacity of 358 mA h g−1 at 0.5 A g−1 after 100 cycles and 276 mA h g−1 at a high rate of 2.0 A g−1. [ABSTRACT FROM AUTHOR]

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/MoS 2 @NC) for use as an electrode material in potassium-ion batteries via a facile spray-drying method. The MX/MoS 2 @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 MoS 2 restacking. This investigation underscores the MX/MoS 2 @NC composite as a promising candidate for potassium-ion battery applications. [Display omitted] • 3D MX/MoS 2 @NC microsphere was successfully synthesized by spray drying method. • 3D structuring of MXene nanosheets effectively addresses their restacking issue. • MX/MoS 2 @NC electrode showed excellent potassium-ion storage performance. • MX/MoS 2 @NC delivered a capacity of 325 mA h g−1 after 500 cycles at 0.5 A g−1. [ABSTRACT FROM AUTHOR]

Combining nanostructured materials with two-dimensional (2D) substrates has long been considered one of the most effective strategies for the production of superior-performance lithium-ion batteries (LIBs). However, the restacking of 2D materials and the volume expansion of the active material during cycling are issues that have yet to be fully addressed. Herein, we propose a facile spray-drying process to successfully encapsulate hollow CoSnO 3 nanoboxes in MXene nanosheets (MX/HCTO), forming three-dimensional (3D) MXene-based microspheres as an anode for LIBs. This 3D structure effectively inhibits the restacking of MXene nanosheets, resulting in a higher surface area and a greater number of active sites for Li+ storage. Encapsulating hollow CoSnO 3 nanoboxes in an MXene shell can also restrict the change in volume during cycling, thus inhibiting the structural collapse of the composite even after long-term cycling. With these advantages, the proposed 3D MX/HCTO composite exhibits a high specific capacity of 670 mA h g−1 at 5.0 A g−1 that is stable over 1000 cycles and a specific capacity of 288.6 mA h g−1 at a high current density of 20.0 A g−1. It's easy synthesis process and inexpensive precursors also ensure that it has the potential to be scaled up for mass production. [Display omitted] • Hollow CoSnO 3 encapsulated with MXene is synthesized by a spray drying process. • 3D structuring of MXene nanosheets effectively inhibits their restacking issue. • Encapsulating by MXene alleviate a huge volume change of CoSnO 3 during the cycling. • 3D MX/HCTO electrode showed excellent electrochemical Li-ion storage performance. • 3D MX/HCTO delivered a capacity of 670 mA h g−1 after 1000 cycles at 5.0 A g−1. [ABSTRACT FROM AUTHOR]

Herein, ternary composite composed of Si@N-doped C coupled with 2D MXene nanosheets (Si@NC/MX) is synthesized by a facile solution-based chemical method followed by thermal treatment. In the aqueous solution, polydopamine (PDA)-coated Si nanoparticles were strongly coupled with MXene nanosheets via chemical interactions. Subsequently, the PDA layers were transformed into N-doped amorphous C during the annealing process. As anodes for Li-ion batteries (LIBs), the rational architecture of composites can effectively prevent particle aggregation and restacking between MXene nanosheets during cycling. Also, the dual protection by the C layer and MXene can alleviate the large volume expansion of the Si anode and provide conductive pathways. Accordingly, the Si@NC/MX composites exhibited a high reversible capacity of 953 mA h g−1 after 300 cycles at 1 A g−1. In addition, the electrode exerted a high reversible capacity of 849 mA h g−1 even at a high current density of 10 A g−1. [Display omitted] [ABSTRACT FROM AUTHOR]