Molybdenum Atom Engineered Vanadium Disulfide for Boosted High-Capacity Li-Ion Storage.

A drawback with lithium-ion batteries (LIBs) lies in the unstable lithium storage which results in poor electrochemical performance. Therefore, it's of importance to improve the electrochemical functionality and Li-ion transport kinetics of electrode materials for high-performance lithium storage. Here, a subtle atom engineering via injecting molybdenum (Mo) atoms into vanadium disulfide (VS2 ) to boost high capacity Li-ion storage is reported. By combining operando, ex situ monitoring and theoretical simulation, it is confirmed that the 5.0%Mo atoms impart flower-like VS2 with expanded interplanar spacing, lowered Li-ion diffusion energy barrier, and increased Li-ion adsorption property, together with enhanced e- conductivity, to boost Li-ion migration. A "speculatively" optimized 5.0% Mo-VS2 cathode that exhibits a specific capacity of 260.8 mA h g-1 at 1.0 A g-1 together with a low decay of 0.009% per cycle over 500 cycles is demonstrated. It is shown that this value is ≈1.5 times compared with that for bare VS2 cathode. This investigation has substantiated the Mo atom doping can effectively guide the Li-ion storage and open new frontiers for exploiting high-performance transition metal dichalcogenides for LIBs.

Highly thermostable white-emitting Ca9ZnK(PO4)7:Ce3+,Dy3+ single-phase phosphor with tunable photoluminescence and energy transfer.

White light-emitting diodes (WLEDs) fabricated with single-phase white phosphor are currently widely used in lighting and displays. Herein, we describe the development of a single-component white-emitting micro-sized powder Ca9ZnK(PO4)7 (CZKP):Ce3+,Dy3+ with high thermal stability. Theoretical and experimental investigations confirmed that the phosphate CZKP with a whitlockite-like structure was suitable as a phosphor host. The photoluminescence of cerium/dysprosium single- and co-doped samples was comprehensively studied. Dipole-dipole interaction resulted in the Ce3+ → Dy3+ energy transfer, which contributed to the spectral regulation for acquiring the white-emitting performance. Moreover, the superior thermal stability of the representative CZKP:0.10Ce3+,0.15Dy3+ phosphor was revealed. Finally, we explored the working performance of single-phase white phosphor-converted WLEDs. The corresponding work shows a successful design for achieving a single-component white phosphor via the Ce3+ → Dy3+ energy transfer approach.