Transition metal dichalcogenides (TMDs) have emerged as potential electrode materials for efficient alkali metal ion storage due to their low cost and high theoretical capacity. However, their practical application is limited by critical issues such as severe volume expansion, low conductivity, and electrochemical inertia. In this talk, the speaker introduces nanostructure design, defect engineering, and interfacial coupling strategies into TMDs, combining Density Functional Theory (DFT) calculations for controllable model construction, electronic property optimization, and energy storage mechanism analysis to achieve efficient, high-capacity, and stable alkali metal ion storage.
1. DFT calculations demonstrate that atomic doping and strong interfacial coupling can help modulate the electronic structure of TMDs and lower diffusion barriers, thereby optimizing ion adsorption behavior and accelerating charge transfer kinetics. Guided by these theoretical calculations, we designed a MOF-derived Cu2S heterostructure supported on an N, S co-doped carbon matrix (Cu2S@NSC). When applied as a negative electrode for lithium-ion batteries, this material exhibits excellent electrochemical performance, maintaining a specific capacity of 512.7 mAh g-1 after 1000 cycles at a current density of 1 A g-1. This systematic theoretical and experimental investigation opens up new avenues and application prospects for high-performance alkali metal-ion battery anodes.

2.  To optimize charge transfer in TMDs and mitigate volume expansion during charging and discharging, we carefully designed a composite material (CoSe0.5S1.5/GA) consisting of highly conductive carbon layers loaded with CoSe0.5S1.5 particles rich in defect sites. The CoSe0.5S1.5 nanoparticles are uniformly grown in situ on porous GA nanosheets. The CoSe0.5S1.5/GA anode maintains a capacity of 310.1 mAh g-1 after 2000 cycles at a current density of 1 A g-1, and the energy density of the CoSe0.5S1.5/GA//AC sodium-ion capacitor can reach 237.5 Wh kg-1. Additionally, DFT calculations reveal that the introduction of Se atoms promotes charge reconstruction and accumulation around S atoms, increasing the defect concentration and bulk disorder, effectively improving the material's electronic structure. The defect engineering strategy and heterointerface modulation employed in this study provide valuable insights for the development of high-performance Na+ energy storage devices.

Transition metal dichalcogenides ，;sodium-ion battery;DFT