The volume expansion behavior and volumetric energy densities of metal alloy negative electrodes (A x M) for metal-ion batteries based on A = Li, Na, K, Mg, Ca and Al are compared. It was found that each metal ion, A, occupies a characteristic volume in alloys which is almost insensitive to the host metal, M. All alloy systems, with the exception of K x M alloys, were found to have similar or greater volumetric energy density than conventional graphitic anodes in Li-ion cells. It is predicted that both the Mg x M and Al x M systems might achieve higher energy densities than possible with any Li-ion negative electrode known and operate at potentials at which organic electrolytes are known to be stable.

Mg[N(SO 2 CF 3 ) 2 ] 2 /Acetonitrile electrolyte was evaluated for use in Mg-ion cells. It was found to have a stable potential range between about −0.2 V and 2.8 V vs. Mg against a stainless steel working electrode. Higher voltages resulted in stainless steel corrosion, while lower voltages resulted in acetonitrile reduction. No Mg plating was observed. Reversible intercalation of Mg into Mo 6 S 8 was demonstrated in this electrolyte with significantly lower irreversible capacity, compared to cycling in Grignard-based electrolytes. Mg[N(SO 2 CF 3 ) 2 ] 2 /Acetonitrile electrolyte may be useful for Mg-ion batteries, if the negative electrode has sufficiently high voltage to avoid acetonitrile reduction.

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High-temperature nanoindentation coupled with in-situ electrical measurements has been used to investigate the temperature dependence (25-200oC) of the phase transformation behavior of diamond cubic (dc) silicon at the nanoscale.1 Along with in-situ indentation and electrical data, Raman and cross-sectional transmission electron microscopy have also been used to reveal the indentation-induced deformation mechanisms in crystalline Si wafer. This study finds that phase transformation and defect propagation within the crystal lattice are not mutually exclusive deformation processes at elevated temperature. Depending on the temperature and loading conditions both the deformation mechanisms can occur up to 150oC but to different extents. It is observed that phase transformation is dominant below 100oC but deformation by twinning along {111} planes dominates at 150oC and 200oC. This work, therefore, provides clear insight into the temperature dependent deformation mechanisms in dc-Si at the nanoscale and helps to clarify previous inconsistencies in the literature.1 1M.

Two and three-electrode electrochemical test cells based on low cost and readily available Conflat vacuum fittings are described. Two-electrode Conflat cells were found to have the same performance as two-electrode coin cells at room temperature, while threeelectrode Conflat cells are much easier to assemble than three-electrode coin cells. Such cells maintain good stack pressure, tolerate high vapor pressure solvents and can operate at temperatures up to 200 • C. Conflat cells are especially useful for high temperature and magnesium battery research, where the need for three-electrode cells operated at elevated temperatures with volatile solvents makes the use of coin cell hardware impractical.