Mg-rich disordered rocksalt oxide cathodes for Mg-ion batteries

Journal article

The discovery of new transition metal (TM) oxide cathodes which can act as intercalation hosts for Mg2+ ions is critical for the development of high energy density Mg-ion batteries. In Li-ion batteries, disordered rocksalts with sufficiently high Li+ charge carrier ion concentration, i.e. Li : TM >1.1, can support fast Li+ diffusion and therefore deliver high capacities (∼300 mA h g−1) and rate performance. Here, we investigate a range of simple Mg-rich disordered rocksalt cathodes, Mg2TMO3 (TM = Mn, Ni, Co), which possess similar charge carrier ion concentrations and similar ratios between the ion size and interstitial tetrahedron height to Li-rich disordered rocksalts. However, even with high carbon loadings, elevated cycling temperatures and reduced particle and crystallite size, no significant Mg2+ deintercalation was observed, indicating that conventional design rules established for Li-rich DRS cannot be simply translated to Mg-rich systems. Despite the lack of activity in Mg-rich oxides, we demonstrate that Mg2+ intercalation into close-packed cubic disordered rocksalts, such as Li2−xMnO2F (x = 1), is possible, opening possible routes to activating Mg-rich systems.

Authors: Quan, Y; Ji, D; Yuan, Y; Xu, H; Qi, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Journal of Materials Chemistry A: materials for energy and sustainability
• Volume: 12
• Issue: 40
• Pages: 27303-27310
• Publication date: 2024-08-12
• Acceptance date: 2024-08-08
• DOI: 10.1039/d4ta02348j
• EISSN: 2050-7496
• ISSN: 2050-7488
• Language: English