Studies on electrochemical lithium insertion in isostructural titanium niobate and tantalate phases with shear ReO3 structure

Lithium insertion properties of Li TiNb2O7 investigated by neutron diffraction and first-principles modelling

“…The theoretical average voltages obtained are consistent with the reversible electrochemical charge/discharge results in the range 2 to 1 V [4,7,8,12]. For a detailed comparison, the experimental discharge curve shown in Fig.…”

“…X-ray powder patterns of (I) Li 3.33 TiNb 2 O 7 obtained by chemical lithiation of TiNb 2 O 7 in this work, and (II) of an electrochemically discharged sample to 1 V as reported in Ref [8]. Fig.…”

“…1(I). For comparison, the diffractogram obtained by Saritha and Varadaraju [8] on a sample of electrochemically lithiated Li x TiNb 2 O 7 after discharge to 1 V against a Li anode, and shown in Fig. 6(b) of their paper, is also displayed in Fig.…”

“…4 of Ref. [8] was considered, and by integrating it numerically in the x ranges 0 to 2.67 and 0 to 3.33 Li/f.u. the average voltages of 1.62 and 1.55 V were obtained, respectively.…”

“…However some of these materials, like the yet promising Li 4 Ti 5 O 12 spinel [3], show a rather limited specific capacity around 150 mA h g À 1 . On the other hand, in recent years the mixed oxide TiNb 2 O 7 was proved to intercalate lithium reversibly with a capacity of 285 mA h g À 1 in the 1.0 to 2.0 V range [4,7,8], thus displaying top qualities for anode applications. Further investigations on this material showed that its performance can still be improved by nanoconfinement techniques [9], or by synthesis in form of nanofibers [10,11] and porous mesostructures [12,13].…”