Various kinds of fluoroalkyl ethers were investigated as diluents to reduce the high viscosity of highly concentrated LiBF4/PC electrolyte solutions. 1,1,2,2–tetrafluoroethyl 2,2,3,3–tetrafluoropropyl ether (HFE) was the most suitable diluent because of a high solubility of LiBF4. 2.50 mol kg−1 LiBF4/PC+HFE (2:1 by volume) was a reasonable compromise to attain a low viscosity (51.7 mPa s) and a low PC/Li molar ratio (2.39). Raman spectroscopy revealed that the fraction of free PC molecules in 2.50 mol kg−1 LiBF4/PC+HFE (2:1) was much smaller than 2.50 mol kg−1 LiBF4/PC (PC/Li molar ratio = 4.00), and that the interactions of HFE with Li+ cations and BF4− anions were very weak. LiNi0.5Mn1.5O4 positive electrodes showed high charge/discharge performance with low irreversible capacities in 2.50 mol kg−1 LiBF4/PC+HFE (2:1), which showed that the highly concentrated LiBF4/PC system can be diluted with HFE without losing the high stability against oxidation.

Charge and discharge properties of spinel LiNi 0.5 Mn 1.5 O 4 positive electrodes were investigated using propylene carbonate (PC)-based concentrated electrolyte solutions in the range of 0.83 (ca. 1 mol dm-3) to 4.45 (nearly saturated) mol kg-1. The solvation state of PC in the concentrated electrolyte solution was studied by Raman spectroscopy. The HOMO energy of PC in Li + (PC) n was evaluated by first-principle calculation to assess the oxidative stability of PC molecules solvating lithium ion. Charge and discharge measurements revealed that the irreversible capacity due to solvent decomposition decreased with increasing the concentration of LiPF 6 , while discharge capacity increased. In addition, cycle performance of LiNi 0.5 Mn 1.5 O 4 positive electrodes was remarkably improved by the use of graphitized Ketjenblack as a conductive additive.

Charge and discharge properties of spinel LiNi 0.5 Mn 1.5 O 4 positive electrodes were investigated using concentrated LiBF 4 /propylene carbonate (PC) electrolyte solutions in the range of 0.833 (ca. 1 mol dm −3 ) to 7.25 (nearly saturated) mol kg −1 . The irreversible decomposition of electrolyte solution was effectively suppressed with an increase in concentration. In addition, the polarization in charge/discharge reactions remained small in the nearly saturated 7.25 mol kg −1 LiBF 4 /PC even though the viscosity was very high and the ionic conductivity was low. The rate capability was higher than that obtained with nearly saturated 4.3 mol kg −1 LiPF 6 /PC. The structure, viscosity, and ionic conductivity of the concentrated LiBF 4 /PC were investigated. Based on the experimental results, the rapid charge/discharge reactions at LiNi 0.5 Mn 1.5 O 4 electrodes were discussed.

In the secondary ion mass spectrometry (SIMS) of organic substances, the molecular weight of the intact ions currently detectable is at best only as high as 1000 Da, which for all practical purposes prevents the technique from being applied to biomaterials of higher mass. We have developed SIMS instrumentation in which the primary ions were argon cluster ions having a kinetic energy per atom, controlled down to 1 eV. On applying this instrumentation to several peptides and proteins, the signal intensity of fragment ions was decreased by a factor of 10(2) when the kinetic energy per atom was decreased below 5 eV; moreover, intact ions of insulin (molecular weight (MW): 5808) and cytochrome C (MW: 12 327) were detected without using any matrix. These results indicate that fragmentation can be substantially suppressed without sacrificing the sputter yield of intact ions when the kinetic energy per atom is decreased to the level of the target's dissociation energy. This principle is fully applicable to other biomolecules, and it can thus be expected to contribute to applications of SIMS to biomaterials in the future.

Charge/discharge characteristics of nickel-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode was investigated in highly concentrated lithium tetrafluroborate (LiBF 4 )/dimethylcarbonate (DMC) electrolytes with better electrochemical stability against oxidation. Raman spectra indicated that almost all DMC solvent molecules coordinated Li + ions, and BF 4 − anions were likely to form aggregates (AGGs) with Li + ions and DMC in the nearly saturated 8.67 mol kg −1 electrolyte. A LiNi 0.8 Co 0.1 Mn 0.1 O 2 |Li half-cell using the nearly saturated 8.67 mol kg −1 LiBF 4 /DMC showed a good cycle performance up to 50 cycles at C/10 rate with a capacity retention of 93.3%. Furthermore, cross-sectional SEM images and EDX mappings revealed that the highly concentrated electrolyte effectively suppressed not only oxidative decomposition of electrolyte solution on the particle surface, but also the particle fracture caused by crack propagation.

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Oxidation of Cu3Au(100) using a hyperthermal O2 molecular beam (HOMB) was investigated by x-ray photoemission spectroscopy in conjunction with a synchrotron light source. From the incident energy dependence of the O-uptake curve, it was determined that the dissociative adsorption of O2 implies a higher activation barrier and therefore less reactivity compared to Cu, owing to the Au alloying. The dissociative adsorption progresses with the Cu segregation on the surface. No prominent growth of Cu2O even for 2eV HOMB suggests that the Au alloying of Cu can serve as a protective layer against further oxidation into the bulk.

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