Gadolinium/chloride co-doping of lithium vanadium phosphate cathodes for lithium-ion batteries

Improved Na storage performance of Na3V2(PO4)3 cathode material for sodium-ion batteries by K-Cl co-doping

“…Table 1 shows that the lattice parameters of a, b, c, and V of the K + and Cl − co-doped NVP are larger than those of the undoped one. The reason for this could be attributed to fact that the radius of K + (1.38 Å) is larger than the Na + (1.02 Å) and the Cl − influence on the electronic cloud of PO 4 3− [29,33], which could broaden the Na + channel. Furthermore, there are no diffraction peaks corresponding to the carbon coating in the XRD patterns of the four groups of composite materials; this is related to the carbon in the material that exists in an amorphous form, or the carbon content is relatively small .…”

“…110.4 at 0.2 C Na 2.90 K 0.10 V 2 (PO 4 ) 3 /C 81.7 at 5 C - [33] 105 at 0.2 C Na 2.79 K 0.07 Ca 0.07 V 2 (PO 4 ) 3 /C 88.6 at 5 C 91% at 1 C after 50 cycles [41] 104 at 0.2 C Na 3 V 1.7 Mn 0.3 (PO 4 ) 3 /C 92 at 2 C - [42] 107.9 at 0. This is due to the synergy of K + and Cl − , which can generate more Na vacancies and expand the diffusion channels, thereby improving the rate performance of NVP [29,31,35]. It is worth noting that the amount of K + and Cl − doping also has a non-negligible impact on the NVP rate performance.…”

“…In addition, doping with cations and anions could be further improved due to the synergy of cations and anions [28]. Chen et al [29] synthesized the Gd 3+ and Cl − co-doped Li 3 V 2 (PO 4 ) 3 via a rheological phase method reaction. Thanks to the effects of the co-doping strategy, the sample delivered much higher discharge capacity, which also proved that this strategy did not destroy the electrochemical performance.…”