ChemInform Abstract: Structural Study of the Li0.5Na0.5MnFe2(PO4)3 and Li0.75Na0.25MnFe2 (PO4)3 Alluaudite Phases and Their Electrochemical Properties as Positive Electrodes in Lithium Batteries.

✍ Scribed by Khiem Trad; Dany Carlier; Laurence Croguennec; Alain Wattiaux; Mongi Ben Amara; Claude Delmas

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 24 KB
• Volume: 42
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.201103005

✦ Synopsis

Structural Study of the Li 0.5 Na 0.5 MnFe 2 (PO 4 ) 3 and Li 0.75 Na 0.25 MnFe 2 (PO 4 ) 3 Alluaudite Phases and Their Electrochemical Properties as Positive Electrodes in Lithium Batteries. -LixNa1-xMnFe2(PO4)3 (x = 0, 0.5, 0.75) is synthesized by a sol-gel method from stoichiometric amounts of Na2CO3, Li2CO3, MnCO3, FeC2O4, and (NH4)H2PO4 in H2O containing HNO3 and citric acid (800 °C, 30 min). The samples are characterized by SEM, powder X-ray and neutron diffraction coupled with DFT calculations, Moessbauer spectroscopy, and electrochemical measurements. The compounds crystallize in the monoclinic space group C2/c and the lithium ions are for the first time accurately localized in the alluaudite structure. The compounds with x = 0.5 and x = 0.75 used as positive electrodes in lithium batteries in the 4.5-1.5 V potential window exhibit smaller electrochemical reversible capacity compared with the non-lithiated x = 0 compound. -(TRAD, K.;