The self-discharge behavior of zinc-air batteries is a critical issue induced by corrosion and hydrogen evolution reaction (HER) of zinc anode. The corrosion reaction and HER can be controlled by a gelling agent and concentration of potassium hydroxide (KOH) solution. Various concentrations of KOH solution and polyacrylic acid have been used for gel electrolyte. The electrolyte solution is prepared with different concentrations of KOH (6 M, 7 M, 8 M, 9 M). Among studied materials, the cell assembled with 6 M KOH gel electrolyte exhibits the highest specific discharge capacity and poor capacity retention. Whereas, 9 M KOH gel electrolyte shows high capacity retention. However, a large amount of hydrogen gas is evolved with 9 M KOH solution. In general, the increase in concentration is related to ionic conductivity. At concentrations above 7 M, the viscosity increases and the conductivity decreases. As a result, compared to other studied materials, 7 M KOH gel electrolyte is suitable for Zn-air batteries because of its higher capacity retention (92.00 %) and specific discharge capacity (351.80 mAh/g) after 6 hr storage.

Background : Alpinia Officinarum Rhizome (高良薑) is recorded as a roots of Alpinia officinarum Hance (Zingiberaceae) in Korea Pharmacopoeia and there is no established confirmation test and method for quantitative determination using marker compound. Using the six marker compounds, pinocembrin, (5S)-5-hydroxy-7- (4-hydroxy-3-methoxyphenyl) -1-phenyl-3-heptanone, pinocembrin, galangin, kaemferide, galangin 3-methyl ether, A simultaneous analysis method was developed to utilize the quality control. Methods and Results : In this study, YMC-pack column (ODS C18, 250 × 4.6 ㎜, 5 ㎛) from YMC was used and the temperature was set at 30℃. A soultion of 0.1% formic acid was using water (mobile phase A) and acetonitrile (mobile B), respectively, and the mobile phase B was set to 15 - 35% for 0 - 15 minutes and 35 - 40% for 15 - 60 minutes. And 270 ㎚ was set as the detection wavelength. The order of the components is pinocembrin (1, Rt: 23.2 min), (5S)-5-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-heptanone (2, Rt: 37.8 min), pinocembrin (3, Rt: 44.9 min), galangin (4, Rt: 46.7 min), kaemferide (5, Rt: 48.6 min), galangin 3-methyl ether (6, Rt: 52.8 min) and Based on the retention time, ultraviolet spectrum and MS value, it was confirmed by comparison with standard compounds. Conclusion : In this study, we developed the simultaneous analysis method by six marker components of the Alpina officinarum Hance extract to develop a quality test method to scientifically identify Alpinia officinarum Hance.