Genuine divalent magnesium-ion storage and fast diffusion kinetics in metal oxides at room temperature

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 118; no. 38; pp. 1 - 8
• Main Authors: Yang, Jinlin, Li, Jibiao, Gong, Wenbin, Geng, Fengxia
• Format: Journal Article
• Language: English
• Published: Washington National Academy of Sciences 21.09.2021
• Subjects: Batteries; Diffusion; Diffusion rate; Electrolytes; Flux density; Intercalation; Interlayers; Ion storage; Ions; Kinetics; Lattices; Layered materials; Lithium; Lithium-ion batteries; Magnesium; Metal oxides; Oxides; Physical Sciences; Polymers; Rechargeable batteries; Room temperature; Titanium oxide; Titanium oxides
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2111549118

Rechargeable magnesium batteries represent a viable alternative to lithium-ion technology that can potentially overcome its safety, cost, and energy density limitations. Nevertheless, the development of a competitive room temperature magnesium battery has been hindered by the sluggish dissociation of electrolyte complexes and the low mobility of Mg2+ ions in solids, especially in metal oxides that are generally used in lithium-ion batteries. Herein, we introduce a generic proton-assisted method for the dissociation of the strong Mg–Cl bond to enable genuine Mg2+ intercalation into an oxide host lattice; meanwhile, the anisotropic Smoluchowski effect produced by titanium oxide lattices results in unusually fast Mg2+ diffusion kinetics along the atomic trough direction with a record high ion conductivity of 1.8 × 10−4 S · cm−1 on the same order as polymer electrolyte. The realization of genuine Mg2+ storage and fast diffusion kinetics enabled a rare high-power Mg-intercalation battery with inorganic oxides. The success of this work provides important information on engineering surface and interlayer chemistries of layered materials to tackle the sluggish intercalation kinetics of multivalent ions.