Figure 1
From: High energy density rechargeable magnesium battery using earth-abundant and non-toxic elements
Preparation of ion-exchanged MgFeSiO4 and charge-discharge profiles.
(a) Schematic illustration of the ion-exchange methodology for the electrochemical synthesis of MgFeSiO4 from Li2FeSiO4. Two-dimensional (2D) framework of Li2FeSiO4 and three-dimensional (3D) framework of FeSiO4 and MgFeSiO4. The 3D framework can incorporate Mg ions in the interspace (void). (b) Charge–discharge profiles for ion exchange process from Li2FeSiO4 to MgFeSiO4. For Li extraction process, two-electrode cells using lithium as counter electrodes were used. Electrolyte was 1 M LiClO4 in propylene carbonate. For Mg insertion process, three-electrode cells (using Mg metal counter electrode and silver reference electrode) were used. Electrolyte was 0.5 M magnesium (trifluoromethylsulfonyl)imide (Mg(TFSI)2) in acetonitrile as solvent. Measurement temperature was 55°C. Current density was 6.62 mA·g−1 (Li2FeSiO4). (c) Charge–discharge profiles of ion-exchanged MgFeSiO4. Three-electrode cells using Mg metal counter electrode and silver reference electrode were used. Electrolyte was 0.5 M magnesium (trifluoromethylsulfonyl)imide (Mg(TFSI)2) in acetonitrile (solvent). Measurement temperature was 55°C. Current density was 6.62 mA·g−1 (MgFeSiO4).
