氯化镁熔盐水合物的电化学性质研究

doi:10.19964/j.issn.1006-4990.2023-0147

Abstract

Abstract:

Molten salt hydrates（MSHs） are inorganic salt melts in general，in which the molar ratio of water-to-salt is less than or equal to the hydration number or coordination number of the cation.To comprehend the dehydration procedure and mechanism of inorganic salt hydrates thoroughly，it is essential to study their characteristics.The conductivity of the MgCl₂-H₂O system at various temperatures was measured，as well as the lowest temperature at which the system with different compositions existed in liquid form.By employing the cyclic voltammetry technique，the electrochemical characteristics of the MgCl₂-H₂O and MgCl₂-KCl-H₂O systems were comprehensively investigated.The conductivity was increased initially and then was steadily decreased when the water content of the MgCl₂-H₂O system was decreased at the same temperature.The conductivity was gradually increased when the temperature was increased at the same water content in dilute solution.The conductivity was decreased with the decrease of water content in concentrated solutions or MSHs at the same temperature；The anodic and cathodic currents in the MgCl₂-H₂O system were dramatically increased with increasing water content after reaching the oxidation or reduction potential in cyclic voltammetry tests.The concentration of Cl^- in the molten salt hydrate system was increased after adding KCl，and Cl^- replaced some water molecules in the hydrated magnesium ions，making hydrogen reduction easier.In the dehydration of MgCl₂·6H₂O，the addition of Cl^- could decrease the hydrolysis reaction of MgCl₂·6H₂O，making it more conducive to dehydration of MgCl₂·6H₂O.

Key words: magnesium chloride, molten salt hydrate, conductivity, cyclic voltammetry

CLC Number:

O646

DONG Mingzhe, LI Kexin, YE Xiushen, MA Zhen, LI Shengting, LI Quan, WU Zhijian. Study on electrochemical properties of magnesium chloride molten salt hydrates[J]. Inorganic Chemicals Industry, 2024, 56(2): 51-56.

Figures/Tables 6

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Table 1

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n（MgCl₂）∶ n（H₂O）	阴阳极峰值电流/A
n（MgCl₂）∶ n（H₂O）	阳极峰值电流	阴极峰值电流1	阴极峰值电流2
1∶20	0.212	-0.199	—
1∶15	0.202	-0.196	—
1∶10	0.122	-0.128	—
1∶9	0.288	-0.144	-0.308
1∶8	0.259	-0.112	-0.264
1∶7	0.223	-0.079	-0.212
1∶6.5	0.150	-0.039	-0.211
1∶6	0.116	-0.024	-0.003

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Study on electrochemical properties of magnesium chloride molten salt hydrates

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