Cathode properties of pyrophosphates for rechargeable lithium batteries

Titanium phosphates as positive electrode in lithium-ion batteries: composition, phase purity and electrochemical performance

“…By increasing the P/Ti molar ratio, the first two plateaux (Fig. 5d), raising a discharge and charge plateau of 2.6 V which is consistent with previous work [10,56,63] or even slightly shifted from these values [64].…”

“…The peaks of sample P-c were more broad compared to the sharp peaks of sample P-d where the all tetragonal (TiO 2 ) not converted fully to cubic (TiP 2 O 7 ), which are dependent on the amount of P/ Ti, once the P/Ti increased, all the tetragonal converted into cubic. The reported 2.6 V for insertion of lithium ion into TiP 2 O 7 [63] is very similar to the value reported here in our work, the little shift of around 20-30 mV could be ascribed to the presence of mixed phase or due to the particle size changing which can have this effect as discussed above. At such a high temperature of 800°C for 3 h, surprisingly, anatase TiO 2 still exists (sample P-c), which we ascribed to the stabilizing effect of phosphate ions and the inhibition effect of conversion into the rutile phase by phosphate, as discussed above.…”

“…Figure 5c showed three plateaux at 1.75, 1.9 and 2.6 V. The first two plateaux are typical characteristics for insertion and extraction of Li + into/from anatase TiO 2 structure, respectively. The extraction of lithium at higher redox potential showed as the third plateau at 2.6 V. The redox value corresponds to the presence of Ti 4+ /Ti 3+ in TiP 2 O 7 [63]. The absence of the corresponding discharge plateau is unclear; however, a mixture of TiP 2 O 7 and TiO 2 might present with a higher percent of the latter.…”

AC conductivity and dielectric behavior in lithium and sodium diphosphate LiNa3P2O7

“…It has also a waked great interest relation to its potential technological applications [3,4] it can be used as catalysts [5], ionic conductors [6], and some of them have been proposed as cathode materials for lithium batteries [7,9]. In deed there are a large number of crystalline materials containing P 2 O 7 groups in the literature for example the new non-centrosymmetric NCS diphosphate compounds with the general formula LiM 3 P 2 O 7 (Li: monovalent, M=Na, K…monovalent) which are potentially applicable as NLO materials.…”

Electrical conduction and thermodynamic properties of K2NiP2O7

“…These and other related diphosphates have awaked great interest in relation to their potential technological applications, as some of them may have magnetic and useful catalytic properties [5][6][7]. Besides, some of them have been proposed as cathode materials for lithium batteries [8,9] and even, as nanoparticles, for decontamination and remediation of water [10].…”