Investigating the asymmetric electrochemical, structural and electronic properties of Mn-rich Li(Mn,Fe)PO 4 electrode materials

Journal article

Olivine-type phosphates LiMnxFe1−xPO4 are attracting increasing interest as positive electrode materials for lithium-ion batteries due to their low cost and good electrochemical performance. However, the effects of the mixed Mn/Fe composition on lithium intercalation and ion transport are not fully characterised, especially in Mn-rich compositions. In this study, the electrochemical, structural and ion transport properties of Mn-rich LiMnxFe1−xPO4 (x = 0.6, 0.7, 0.8) (LMFP) are investigated using a combination of experimental and materials modelling techniques. Considerable asymmetry in charge/discharge profiles is found, which highlights the complexity of the mixed-metal system. An intricate lithium intercalation mechanism is observed, including both solid solution and two-phase regions. While the Fe/Mn cation disorder causes the oxidation to proceed mostly via a solid solution mechanism, the Mn plateau remains associated with a two-phase process. Ab initio simulations indicate that Li+ diffusion occurs along one-dimensional channels parallel to the crystallographic b-axis following a curved trajectory, and find favourable Li/Fe and Li/Mn anti-site defect formation. Analysing the band gaps of the lithiated and delithiated phases revealed that Mn substitution of Fe can improve the electronic conductivity, suggesting asymmetric electronic behaviour.

Authors: Ricci, B; Mocanu, F; Chatzogiannakis, D; Fuentes, V; Black, AP

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Journal of Materials Chemistry A: materials for energy and sustainability
• Publication date: 2026-02-09
• Acceptance date: 2026-02-06
• DOI: 10.1039/d5ta10330d
• EISSN: 2050-7496
• ISSN: 2050-7488
• Language: English
• Keywords: Electrode; Electrochemistry; Electronics; Nanoarchitectures for lithium-ion batteries