The Electrodeposition of Magnesium

Paving the Way towards Highly Stable and Practical Electrolytes for Rechargeable Magnesium Batteries

“…[8] However, the relatively low oxidation stability of most Grignard reagents (about 1.5 V vs. Mg; Table 1) and their reactivity towards many cathode materials precluded their use as electrolytes in battery systems. [8] However, the relatively low oxidation stability of most Grignard reagents (about 1.5 V vs. Mg; Table 1) and their reactivity towards many cathode materials precluded their use as electrolytes in battery systems.…”

“…Over 80 years ago, it was discovered that ethereal solutions of Grignard reagents were capable of supporting the plating of highly pure Mg metal. [8] However, the relatively low oxidation stability of most Grignard reagents (about 1.5 V vs. Mg; Table 1) and their reactivity towards many cathode materials precluded their use as electrolytes in battery systems. [9, 5a] Capitalizing on their compatibility with Mg metal, initial research and development efforts relied on organomagnesium compounds as platforms to create electrolytes with increased anodic stability.…”

Electrochemistry of Organomagnesium Compounds

“…Aqueous solutions as well as those of the most common organic solvents cannot be used for this purpose. On the other hand, exceptionally good results were obtained using ethereal solutions of 5, following evidence of magnesium deposition from these solutions reported in early studies 13,14,30,90 . Patented methods 91 -93 preferably used THF solutions of 5b, if 8g was added after starting electrodeposition at a rate sufficient to dissolve sponge-like magnesium deposits but low enough to avoid corrosion of the magnesium compact layer 91 .…”

Progress of Electrolytes for Magnesium Rechargeable Batteries and Future Challenges

“…マグネシウム金属の電析の研究は，1900 年代初頭にさかの ぼる[14][15][16][17][18][19] ．Fig. 1 に示すように，マグネシウムは非常に卑な金属なので，水溶液からの電析はほぼ不可能で，非プロトン 性有機溶媒，特にエーテル溶液中からのマグネシウム金属の 電析が古くから研究されてきた．例えば 1927 年に Gaddum の THF 溶液の組成の最適化を行うとともに，その他の塩， 特に Mg(BBu 2 Ph 2 ) 2 などの有機ほう酸塩 (Bu は n-ブチル基) や，種々の正極活物質の提案を行った 20) ．さらに同論文中で は，グリニャール試薬/THF 溶液への AlCl 3 添加により，マ 3 と PhMgCl を 1:2 で混合した THF 溶液，いわゆる all phenyl complex (APC)溶 液 が 報 告 さ れ た 9,10) ． さ ら に， EtMgCl と hexamethyldisilazane から合 成した hexamethyldisilazide magnesium chloride (HMDS-MgCl) と AlCl 3 を溶 解させ た THF 溶液 25) や tris(3,5-dimethylphenyl)borane, (3,5-xylyl) 3 B/ PhMgCl の THF 溶液 26) が報告され，電位窓は最大で 3.5 V 程 度まで拡大した．なお，論文中では(3,5-xylyl) 3 B を Mes 3 B と 記 載 されているが， Mes は 通 常 メシチル基 (2,4,6-trimethylphenyl 基) を意味するため，ここではより一般的な表現で記 マグネシウムボロハイドライド Mg(BH 4 ) 2 をマグネシウム塩 と し て 用 い た， THF も し く は 1,2-dimethoxyethane (monoglyme, G1) 電解液を報告している 31) ．電位窓の酸化端はおよ そ 2 Vvs.…”