Front Cover: In article number BTE2.20230021, Lianghao Yu and co-workers have shown that in the future, MXene will be utilized as a negative electrode material for sodium-ion batteries applied in wind, solar, and power grids. The molten salt F-free etching method is highly secure and enables the preparation of MXene negative electrodes on a significant scale, which aligns with the concept of sustainable development. In the image, a bullet train powered by MXen-based materials is traveling under the blue sky and white clouds, transporting passengers between green plants. On both sides of the bullet train are various energy storage devices, indicating the widespread use of MXene material obtained via molten salt F-free etching method as a negative electrode material for sodium-ion batteries, as well as its safety and environmental friendliness.