Iron and Manganese Pyrophosphates as Cathodes for Lithium-Ion Batteries

Journal Article · Thu Oct 15 00:00:00 EDT 2015 · Chem. Mater.

DOI:https://doi.org/10.1021/cm102922q· OSTI ID:1026532

Zhou, Hui; Upreti, Shailesh; Chernova, Natasha A.; Hautier, Geoffroy; Ceder, Gerbrand; Whittingham, M. Stanley ^[1]

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1. Binghamton

The mixed-metal phases, (Li{sub 2}Mn{sub 1-y}Fe{sub y}P{sub 2}O{sub 7}, 0 {le} y {le} 1), were synthesized using a 'wet method', and found to form a solid solution in the P2{sub 1}/a space group. Both thermogravimetric analysis and magnetic susceptibility measurements confirm the 2+ oxidation state for both the Mn and Fe. The electrochemical capacity improves as the Fe concentration increases, as do the intensities of the redox peaks of the cyclic voltammogram, indicating higher lithium-ion diffusivity in the iron phase. The two Li{sup +} ions in the three-dimensional tunnel structure of the pyrophosphate phase allows for the cycling of more than one lithium per redox center. Cyclic voltammograms show a second oxidation peak at 5 V and 5.3 V, indicative of the extraction of the second lithium ion, in agreement with ab initio computation predictions. Thus, electrochemical capacities exceeding 200 Ah/kg may be achieved if a stable electrolyte is found.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: DOE - BASIC ENERGY SCIENCES
• OSTI ID: 1026532
• Journal Information: Chem. Mater., Vol. 23, Issue (2) ; 01, 2011; ISSN 0897-4756
• Country of Publication: United States
• Language: ENGLISH