Potential Applications of Heterostructures of TMDs with MXenes in Sodium-Ion and Na-O2 Batteries
Chao Tang 1, Yuxiang Min 1, Chongyang Chen 1, Weiwei Xu 1, Lai Xu 1,*
1Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-AiRoad, Suzhou 215123, China.
Na-ion batteries are viewed as the alternative to Li-ion batteries for similar electrochemical properties, while they always suffer from a low capacity. Na–O2 batteries are important due to their high energy density; however, they are usually limited by high overpotential. In this manuscript, 16 different heterostructures of TMDs with MXenes (bare and O-terminated case) are constructed and their potential in the application of sodium-ion batteries (SIBs) and Na–O2 batteries is explored. Among these structures, it is proved that only the heterostructures of VS2 with O-terminated MXenes could load five layers of Na+ ions, while the others will have a distortion when Na+ ions intercalate or diffuse in the interlayer or the second adsorption layer. The ultrasmall diffusion barrier of Na+ ion denotes that these structures have a fast charge/discharge speed, and the ultrasmall open circuit voltages (OCVs) of 0.18 and 0.21 V prove that they are promising candidates for SIBs. The ultralow overpotential 0.55 V/0.20 V for the ηORR/ηOER means that the O facet of the VS2/Ti2CO2 heterostructure also has a great potential in the application of Na–O2 batteries. These simulations prove that the heterostructures constructed by TMDs with MXenes have great potential in SIBs and Na–O2 batteries and are important for future battery design.