2022 Fiscal Year Final Research Report
Feasibility Studies of Graphite as a Negative Electrode Material for Mg-Ion Batteries: Reconsideration from the Potentials of Counter Electrodes
| Project/Area Number |
20H02840
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 36020:Energy-related chemistry
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| Research Institution | Shinshu University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 黒鉛層間化合物 / 多価カチオン電池 / 弱配位性電解液 / ラマン分光解析 / 配位子 / エレクトロクロミック |
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| Outline of Final Research Achievements |
Rechargeable Mg-ion batteries which are independent of Li have attractive much attention as a next-generation energy device. This is motivated by the high theoretical capacity and the element abundance of Mg (2205 mA h g－1/3832 mA h cm－3). There are few reports on the use of graphite as a negative electrode material even when its scope is expanded to include not binary but ternary Mg-graphite intercalation compounds (GICs). In this work, we studied the electrochemical formation of Mg-GICs in DMF-based electrolytes to achieve a capacity of 180 mA h g－1 by reversible intercalation/deintercalation of solvated Mg2+. In addition, we focused on size and donor number of solvent and investigated the solvent effect on the formation of ternary Mg-GICs. It was found that Mg ions encapsulated by 15-crown-5-ether or18-crown-6-ether were inserted into graphite interlayers in EC:DEC and DME-based electrolytes, respectively.
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| Free Research Field |
電気化学・材料化学・溶液化学
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| Academic Significance and Societal Importance of the Research Achievements |
マグネシウム二次電池におけるMg金属負極の析出－溶解（充放電）の可逆性を高めるうえではハロゲン化物を電解液に含む系が多く，蓄電池デバイスの構成要素である集電体などを腐食する懸念がある．本研究で見い出した黒鉛電極の充放電（Mgイオンの共挿入）反応においては，溶媒には選択肢が限られるものの，Mg塩には腐食性を示さない塩化物を必要とせずデバイス構築においては利点があるものと考えられる．また，仮に黒鉛を電極活物質として利用することができれば，従来のLIBの生産プロセスをそのまま踏襲することができ，学術的だけでなく産業的にも意義があるだろう．
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