Crystal Structure and Cation Transport Properties of the Layered Monodiphosphates: Li9M3(P2O7)3(PO4)2(M=Al, Ga, Cr, Fe)

Electrochemical performance of LiFe1−xVxPO4/carbon composites prepared by solid-state reaction

“…Yin et al reported that Li 3 V 2 (PO 4 ) 3 is a promising cathode material due to its good ion mobility, high reversible capacity and high operating voltage [13]. For LiFe 1−x V x PO 4 /C (x = 0.1, 02, 0.3, 0.4) samples, Li 9 Fe 3 P 8 O 29 peaks can be observed, which is a Li-inert compound for its balanced valence and unstable structure [14]. From LiFe 0.9 V 0.1 PO 4 /C to LiFe 0.6 V 0.4 PO 4 /C, the intensities of Li 9 Fe 3 P 8 O 29 peaks become smaller which is attributed to the synthesis of Li 3 V 2 (PO 4 ) 3 .…”

“…4b, the peaks I and IV centered around 3.5 V which has a peak separation of 0.5 V correspond to the charge/discharge reaction of Fe 3+ /Fe 2+ . The peaks II and III centered around 4.05 V are the first Li ion insertion/extraction in Li 3 V 2 (PO 4 ) 3 , the peaks V and VI centered around 3.7 V are the second Li ion insertion/extraction, and the only reduction peak without oxidation peak at about 3.5 V may be the third Li ion [14]. In LiFe 0.7 V 0.3 PO 4 /C and LiFe 0.6 V 0.4 PO 4 /C, there is another reduction peak VIII without oxidation peak at about 3.75 V which may be attributed to the redox reactions among vanadium of different valences in composite.…”

New monodiphosphate Li9Cr3(P2O7)3(PO4)2: X-ray crystal structure and vibrational spectroscopy

“…At the present, we are interested in the preparation of single crystals of Li 6 Cr 2 (P 2 O 7 ) 3 diphosphate from melted samples under phosphate flux. In the this work, we discuss about the synthesis and the single-crystal X-ray structure of the new phase Li 9 Cr 3 (P 2 O 7 ) 3 (PO 4 ) 2 , which resulted to be isostructural within trigonal space group P 3 3c1 to Li 9 Me 3 (P 2 O 7 ) 3 (PO 4 ) 2 (Me ¼ Al(III), Fe(III)) 2 [1], and about the results of IR and Raman spectroscopy.…”

The first investigation of the synthetic mechanism and lithium intercalation chemistry of Li9Fe3(P2O7)3(PO4)2/C as cathode material for lithium ion batteries

“…(PO 4 ) 3− and (P 2 O 7 ) 4− , coexist in Li 9 Fe 3 (P 2 O 7 ) 3 (PO 4 ) 2 which employs earth-abundant iron as the redox center. Its crystal structure was first described by Poisson et al in 1998, 25 and it was not until 2010 that it found its application as a photocatalyst working under visible light. 33 Until now, there is no report on its application as a cathode material for lithium battery.…”

“…Mixed-polyanion compounds such as LiFe 2 (SO 4 ) 2 (PO 4 ), 22 [25][26][27] and Li x Na 4−x Fe 3 (PO 4 ) 2 (P 2 O 7 ) (x = 0-3) 28 have two kinds of polyanions. Some of them show fascinating physicochemical characteristics as cathode materials for lithium batteries.…”