Effect of heteroatoms-doped carbon decoration on the cathode surface for sodium-ion batteries

Critical review of the recent progress and challenges of polyanion Na3V2(PO4)3 cathode materials in rechargeable sodium-ion batteries

“…171 Further, Shaji et al for the first time successfully synthesized an N, S-doped carbon-decorated NVP (NSC@NVP) cathode utilizing l -cysteine as the only source of carbon doped with heteroatoms in SIBs. 182 In the NSC@NVP composite, 5 wt% of l -cysteine (5-NSC@NVP) delivered a high discharge capacity of 115.8 mA h g −1 at 0.1C (pristine NVP-94.6 mA h g −1 at 0.1C) and retained a capacity of 101 mA h g −1 at 1C after 300 cycles. The high electrochemical performance of 5-NSC@NVP is mainly ascribed to the improvement in electron and ion synergy conductivity enabled by the defects and active sites in the N, S-doped carbon.…”

Nanoporous Cathode Material for High-Energy-Density Sodium-Ion Batteries

“…In contrast, polyanionic cathode materials with high-voltage plateau and stable crystal structure have attracted the attention of researchers. , NASICON-type Na 3 V 2 (PO 4 ) 3 with a 3D structural framework is the most typical polyanionic cathode material. The [V 2 (PO 4 ) 3 ] 3– is a “lantern-shaped” skeleton consisting of a VO6 octahedron and a PO 4 tetrahedron co-topped along the c -axis. , In addition, Na + occupies the vacant position/channel of [V 2 (PO 4 ) 3 ] 3– , with two Na + occupying the Na(2) position (6b) along with one Na + occupying the Na(1) position (18e). When NVP is charged to voltage plateau (3.4 V), the 2 Na + in the Na(2) position are completely removed, consequently a theoretical specific capacity of 117 mAh g –1 was produced. − At that time, polyhedral channels formed by the joining of three VO 6 octahedra and three PO 4 tetrahedra have an approximate diameter equal to twice the sum of their radii of Na + and O. − The open three-dimensional framework and wide sodium-ion diffusion channels enable NVP to have excellent Na + migration ability .…”

“…The [V 2 (PO 4 ) 3 ] 3− is a "lantern-shaped" skeleton consisting of a VO6 octahedron and a PO 4 tetrahedron co-topped along the caxis. 19,20 In addition, Na + occupies the vacant position/channel of [V 2 (PO 4 ) 3 ] 3− , with two Na + occupying the Na(2) position (6b) along with one Na + occupying the Na(1) position (18e).…”