Effects of Zr doping to improve ionic conductivity and lithium-diffusion kinetics of β-LiVOPO4 cathode material

Improved cycling stability of V2O5 modified spinel LiMn2O4 cathode at high cut‐off voltage for lithium‐ion batteries

“…The D Li+ estimated from the CV indicates three magnitude orders higher than the D Li+ obtained from EIS technique. This is most likely due to the fact that EIS measurements were taken under more equilibrium conditions 62,63 . Additionally, the large difference in D Li+ values is mostly because of the different assumptions about the geometric factors (such as the uncertainty of true cross‐sectional area, A ) and the different approximate formula used to compare the values, which should affect the absolute value of D Li+ 64 .…”

“…This is most likely due to the fact that EIS measurements were taken under more equilibrium conditions. 62,63 Additionally, the large difference in D Li+ values is mostly because of the different assumptions about the geometric factors (such as the uncertainty of true cross-sectional area, A) and the different approximate formula used to compare the values, which should affect the absolute value of D Li+ . 64 Though the calculated value of the D Li+ varies depending on technique used, both EIS and CV techniques confirm that V 2 O 5 coating layer considerably improves the lithium-ion mobility, giving rise to the increased D Li+ value.…”

Recent Developments of Nanomaterials and Nanostructures for High‐Rate Lithium Ion Batteries

“…[101] Similarly, the influence of doping zirconium (Zr) in β-LiVOPO 4 cathode on diffusion coefficients was analysed by Park et al by three different techniques, including slow-scan cyclic voltammetry (SSCV), standard potentiostatic electrochemical impedance spectroscopy (SPEIS), and potentiostatic intermittent titration technique (PITT). [102] As shown in Figure 11a, the diffusivity (evaluated by all three techniques) of Zr-doped β-LiVOPO 4 (β-LiV 0.97 Zr 0.03 OPO 4 ) is higher than that of pristine β-LiVOPO 4 . This is because the volume of crystal unit is expanded from 336.38 to 336.49 Å 3 after Zr doping, which facilitates the diffusion of lithium ions during intercalation/deintercalation.…”

“…This is because the volume of crystal unit is expanded from 336.38 to 336.49 Å 3 after Zr doping, which facilitates the diffusion of lithium ions during intercalation/deintercalation. [102] In addition, co-doping Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 with niobium (Nb) and fluorine (F) has been experimentally proved to increase the diffusion coefficient of lithium ions from 0.85 × 10 À 11 to 2.61 × 10 À 11 cm 2 s À 1 (estimated based on the results from electrochemical impedance spectroscopy), which is due to an increase in the interlayer distance of (003) facets from 0.468 to 0.474 nm. [103] In addition to experimental studies, there are also some theoretical reports investigating the influence of doping on lithium ion migration.…”

“…Antisite defect is considered as one type of point defects, which is formed when two or more atoms exchange their positions , and PITT (circles). [102] Reproduced with permission from Ref. [102].…”