Two-dimensional monoelement nanosheets produced from bulk crystals for potassium-ion storage

Two-dimensional (2D) nanomaterials, particularly anisotropic monoelemental semiconductors, have attracted considerable attention for optoelectronic and electronic applications. Herein, a general substrate-free solution process is presented to prepare 2D non-layered selenium (Se)/tellurium (Te) and layered antimony (Sb) from bulk crystals. As a representative anode for K+ storage, the 2D Sb/mesoporous carbon (CMK-3) composite exhibits a high capacity up to 390.1 mAh/g at 50 mA g+1 and ultra-high retention of 98.9 % after 200 cycles, demonstrating that the reduced particle size and expanded interlayer distance effectively shorten the ionic diffusion pathway for fast kinetics.