Electrochemical Property:  Structure Relationships in Monoclinic Li_3-yV₂(PO₄)₃

Abstract

Monoclinic lithium vanadium phosphate, alpha-Li(3)V(2)(PO(4))(3), is a highly promising material proposed as a cathode for lithium-ion batteries. It possesses both good ion mobility and high lithium capacity because of its ability to reversibly extract all three lithium ions from the lattice. Here, using a combination of neutron diffraction and (7)Li MAS NMR studies, we are able to correlate the structural features in the series of single-phase materials Li(3-y)V(2)(PO(4))(3) with the electrochemical voltage-composition profile. A combination of charge ordering on the vanadium sites and lithium ordering/disordering among lattice sites is responsible for the features in the electrochemical curve, including the observed hysteresis. Importantly, this work highlights the importance of ion-ion interactions in determining phase transitions in these materials.

Vanadium-based nanostructure materials for secondary lithium battery applications

“…Its VO 6 octahedra and PO 4 tetrahedra are connected through oxygen vertices, where three crystallographic interstitial voids are available for the occupancy of lithium. 94 Their structural differences result in distinct electrochemical reactions. Rhombohedral LVP is reported to undergo a twophase transition between the compositions of Li 3 V 2 (PO 4 ) 3 and LiV 2 (PO 4 ) 3 (3.7 V), involving a V 3+ /V 4+ redox couple.…”

The Electrochemical Performance of Li3V2(PO4)3/Graphene Nano-powder Composites as Cathode Material for Li-ion Batteries

“…4a shows the first charge-discharge curves of the LVP and LVP/ graphene composite in the potential range of 3.0-4.3 V at 0.1 C. As shown in Fig. 4a, all the composites showed obviously three charge and discharge plateaus, which are identified as the two-phase transition processes during electrochemical reactions [6][7][8][9]30]. The first oxidation peaks around 3.6 and 3.7 V correspond to the removal of first Li in two steps, since there is an ordered Li 2.5 V 2 (PO 4 ) 3 phase.…”

“…However, despite of these advantages, the intrinsic low electronic conductivity of about 2.3 × 10 −8 Scm −1 at room temperature, which is major drawback for the application of the LIBs, limits its rate capability [6,10]. In order to improve the low electronic conductivity, many efforts such as minimizing the particle size, doping with metal or surface coating with conducting materials were conducted [11][12][13][14][15][16][17][18][19][20][21][22].…”

“…As the properties of the cathode material determine the performance of the LIB, it is essential to develop the new active materials for the cathode in advanced battery systems. Recently, the monoclinic Li 3 V 2 (PO 4 ) 3 has been considered as cathode materials for the advanced LIBs due to the lithium ion mobility, high reversible capacity, high operating voltage and safety [4][5][6][7][8][9]. It can also reversibly extract/insert two lithium ions between 3.0 and 4.3 V based on the V 3+ / V 4+ redox couple (1 C = 133 mAh g…”

Synthesis and Electrochemical Properties of Li3V2(PO4)3-LiMnPO4Composite Cathode Material for Lithium-ion Batteries

“…The diffraction patterns of our prepared composite clearly overlay olivine LiMnPO 4 and monoclinic Li 3 V 2 (PO 4 ) 3 , which is consistent with those previously reported. [13][14][15] The diffraction patterns were indexed and their lattice parameters are calculated based on Li 3 V 2 (PO 4 ) 3 structure in Table 1 and LiMnPO 4 structure in Table 2. The lattice parameters are clearly increased in our composite sample, indicating the change in the lattice distance for the lithium de-/intercalations in the compounds.…”