Lithium chloride-modified magnesium hydroxide is a candidate material for thermochemical energy storage. In this work, the effects of lithium chloride mixing ratio, hydration temperature, and water vapor pressure on the hydration behavior of the material are investigated. Heat output densities for all experimental conditions are evaluated. The heat output density per unit weight of lithium chloride-modified magnesium hydroxide, at a molar mixing ratio of 0.10 mol of lithium chloride per mol of magnesium hydroxide, is 1.40 × 103 kJ kg–1 at a hydration temperature of 110 °C and a water vapor pressure of 57.8 kPa. This value is higher than the heat output density of authentic magnesium hydroxide.

The dehydration behaviors of metal-salt-added magnesium hydroxide as chemical heat storage media were studied. Dehydration temperature of magnesium hydroxide, which was corresponding to heat storage temperature, was dropped from 277 to 233 °C by addition of lithium chloride. The heat storage capacity of 6.8 wt % LiCl/Mg(OH)2 (816 MJ m−3) was 11 times as high as one of authentic Mg(OH)2 under the heat storage operation at 280 °C.

The mixing effect of transition metal ion into magnesium hydroxide on dehydration and hydration reactivity was studied to develop a new material for chemical heat-storage, because the mixing effect was expected to reduce dehydration-temperature, corresponding to heat-storage temperature, of authentic magnesium hydroxide. Two-components composite materials mixed with some content of nickel ion or cobalt ion into magnesium hydroxide were tested, respectively. It was demonstrated that the dehydration-temperatures of the composites were shifted to lower temperature below 300°C with increase of nickel or cobalt content in comparison with dehydration-temperature of authentic magnesium oxide of 350°C. These composites showed higher hydration reactivity than that for authentic magnesium oxide under the same reaction condition, and were expected to be applicable to heat utilization of middletemperature waste heat less than 300°C.

An efficient σ-Lewis acidic Ag(I) complex has been obtained by complexation with an electron-donating π-conjugated molecule as a side-on π ligand. The σ-Lewis acidity is possibly derived from the controlled linear coordination around Ag(I) due to the π ligand. A combination of UV-Vis absorption spectroscopy and X-ray absorption near-edge structure analyses clearly revealed that the complex is formed by π ligand-to-Ag(I) charge-transfer interaction. The σ-Lewis acidity was evaluated by IR spectroscopy using 2,6-dimethyl-γ-pyrone as the σ-Lewis basic molecule.

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