Fig. 1

Schematic diagram of the crystal structure of TiNb2O7 and possible positions of Li+ (viewed along the [010] direction)[8]"

Fig. 2

CV curves of a TNO single particle at a scan rate of 0.1 mV/s[18]"

Fig. 3

Structural changes of Li x TiNb2O7 during Li insertion-extraction. (a) In situ XRD patterns collected during initial discharge and charge at a constant current rate of C/8 between 1.0 V and 3.0 V; (b) The unit cell volume “V” and lattice parameter “b” calculated from “Le Bail fitting” as a function of “ x ” in Li x TiNb2O7 (“ x ” is derived from the capacity obtained; open circle: during discharge; solid dot: during charge)[11]"

Fig. 4

(a) FESEM images of the as prepared TiNb2O7 microspheres; (b) the multi-rate testing at the discharge currents of 0.5 C, 1 C, 2 C, 5 C, 10 C, 20 C, respectively; (c) Cycle performances of TiNb2O7 microspheres at the rate of 10 C[16]"

Fig. 5

(a) SEM image of the n-TNO; (b) Capacity retention of the n-TNO and m-TNO at different current densities; (c) Cyclic performance of n-TNO at 5 C for 10000 cycles (after aging at 0.1 C for 3 cycles)[21]"

Fig. 6

SEM image of M-TNO (a); SEM image of N-TNO (b); TEM image of M-TNO (c); TEM image of M-TNO (d);Cycle performances of M-TNO at 1 C (e); and N-TNO, M-TNO at 10 C,(f); rate capabilities of M-TNO and N-TNO at different rates[22]"

Fig. 7

(a) Charge-discharge curves at 1 C, (b) rate capabilities after charging at 1 C for TNO (black squares/lines) and Mo-TNO (red squares/lines)[23]"

Fig. 8

(a) Cycle performance of TNOMs, V0.015-TNOMs, V0.030-TNOMs and V0.045-TNOMs at 0.5 C. (b) Discharge capacities of TNOMs, V0.015-TNOMs, V0.030-TNOMs and V0.045-TNOMs at various rates (c) Cycling performance of TiNb1.97V0.03O7 at 10 C[24]"

Fig. 9

(a) Cycle performance of HTNO@C spheres (100 cycles), HTNO spheres (100 cycles) and STNO spheres (70 cycles) at 0.25 C; (b) Rate capability under different current rates of HTNO@C spheres, HTNO spheres and STNO spheres; (c) Cycle performance of HTNO@C spheres for 500 cycles at 0.25 C[38]"

Table 1

Preparation method and electrochemical properties of TiNb2O7 as LIB anode"