New Cathode Materials for Rechargeable Lithium Batteries: The 3-D Framework Structures Li3Fe2(XO4)3(X=P, As)

✍ Scribed by C. Masquelier; A.K. Padhi; K.S. Nanjundaswamy; J.B. Goodenough

• Book ID: 102604216
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 367 KB
• Volume: 135
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7629

✦ Synopsis

Electrochemical insertion of lithium into four Li 3 Fe 2 (XO 4 ) 3 polymorphs (X ‫؍‬ P or As) with 3-D framework structures was carried out in ''Li/LiClO 4 (PC:DME)/cathode'' coin cells. Approximately 2 Li per formula unit could be reversibly inserted into the three different structures, which corresponds to the reduction of all Fe 3؉ to Fe 2؉ between 2.5 and 3.5 V vs lithium. The position of the Fe 3؉ /Fe 2؉ redox couple below the lithiumanode Fermi energy is nearly independent of the structure and of whether X ‫؍‬ P or As. There is, however, a clear dependence of (i) the shape of the V cc vs x curves for Li 3#x Fe 2 (XO 4 ) 3 and (ii) the charge-discharge rate capabilities on the crystal structure of the cathode material.