Enhanced Li-Ion-Storage Performance of MoS2 through Multistage Structural Design

Inspired by a folded protein, multistage structural MoS2 is designed as an advanced anode material for lithium-ion batteries (LIBs). Density functional theory (DFT) calculations are initially performed, demonstrating that the ideal primary structure (P-MoS2) has saw-tooth-like edges terminated by Mo atoms and the desired secondary structure (C-MoS2) may form via crumpling. For the latter, more exposed (002) planes exist within the wrinkled parts, creating more active sites and promoting isotropic Li+ insertion. Importantly, the rate capability and capacity of a MoS2 anode are enhanced after such a P-MoS2 to C-MoS2 transition: a superb specific capacity of 1490 mAh/g for C-MoS2 at 0.1 A/g (vs. 1083 mAh/g for P-MoS2), an excellent cycling stability (858 mAh/g after 450 cycles at 0.5 A/g), and an improved rate capability of 591 mAh/g at 1 A/g (vs. 465 mAh/g) are documented. The curving effects and mechanical properties of a single C-MoS2 particle are further visualized by insitu TEM. Drastically enlarged spacing changes upon Li-insertion and high elasticity are confirmed, which lead to enhanced LIB performances and the excellent mechanical strength of C-MoS2. The present multistage design of a MoS2 structure should pave the way toward high-energy MoS2 anode materials for future LIBs.