No abstract

High-performance thin-film LiCoO2 cathodes were successfully fabricated by aluminum-oxide coating. Both the galvanostatic charge−discharge experiments and the cyclic voltammograms (CVs) showed enhanced electrochemical properties in the Al2O3-coated LiCoO2 films compared to those in the uncoated ones. The improved cycling behaviors in the coated samples are caused by the suppression of cobalt dissolution from the LiCoO2 thin films, with the formation of an aluminum-oxide solid electrolyte residing between the LiCoO2 cathode and liquid electrolyte. Galvanostatic intermittent titration technique (GITT) results clearly showed that the Al2O3-coated samples had higher Li diffusivities than the uncoated ones after 80 cycles. The effect of Al2O3 thickness on the electrochemical properties up to 300 nm was also studied.

Packed to capacity: The incorporation of mesoporous structures as a buffer layer enhances the structural stability of tin phosphate and alleviates the volume expansion of the tin phosphate anode during Li alloying/dealloying (see TEM image). The mesoporous tin phosphate/Sn2P2O7 composite anode shows a large initial capacity (721 mA h g−1) and excellent cyclability (587 mA h g−1 at the 30th cycle).

Mn-doped zinc sulfide nanoparticles were synthesized using a liquid-solid-solution method, as a simple synthetic route for preparing nearly monodispersed nanocrystals with a diameter of 7.3±0.7nm. The influence of doping concentration for optimum luminescence properties was studied with the nonuniform distribution of local strain and the capping effect. The improved photoluminescence properties of the 450°C-annealed samples with 1.0at.% Mn doping are attributed to both the removal of water/organics and the enhanced crystallinity (reduced local strain).