Aleksey E. Kuznetsov

Aromatic Mercury Clusters in Ancient Amalgams

nonuniform strain during delithiation produces a new-class of cathode materials, which are extremely tolerant to electrochemical cycling. Note that the lattice constant c of the ZrO2coated LiCoO2 exhibits negligible shift in the range 0< x< 0.7, which indicates that the original hexagonal symmetry is unaffected by delithiation. A sol ± gel coating of ZrO2, which has the highest fracture toughness, leads to the formation of a fracture-toughened thin-film solid solution (tens of nm thick) near the particle surface. This film significantly improves the structural stability of the cathode material by suppressing c-axis expansion (or phase transition), thereby preventing capacity fading during electrochemical cycling. In conclusion, the encapsulation of LiCoO2 powders by thin-film coating of high-fracture-toughness oxides effectively suppresses the lattice-constant changes during electrochemical cycling and thereby suppresses phase transitions. The order of capacity retention correlates well with the fracture toughness of the coated thin-film oxides. This innovative technology can be applied to any cathode material that has an accompanying lattice strain (or phase transition) during cycling. The commercial potential of a rechargeable Li-ion battery is enormous.

Theoretical Evidence of Aromaticity in X3− (X = B, Al, Ga) Species

We investigated the electronic structure and chemical bonding of the B3−, Al3−, and Ga3− anions, and the gas phase NaB3, NaAl3, and NaGa3 molecules. We found that the ground state of the neutral gas phase salts contains an equilateral triangular anion interacting with a Na+ cation. The B3−, Al3−, and Ga3− anions possess two delocalized π electrons and are found to be aromatic. The triangular anions have been shown to be related to recently synthesized organometallic compound containing an aromatic -Ga32− unit, but they are differ from them by four valence electrons. The reason for earlier appearance of the π-orbital in the B3−, Al3−, and Ga3− anions is discussed.