Carbon-Coated Na₃V₂(PO₄)₃ Embedded in Porous Carbon Matrix: An Ultrafast Na-Storage Cathode with the Potential of Outperforming Li Cathodes

Abstract

Sodium ion batteries are one of the realistic promising alternatives to the lithium analogues. However, neither theoretical energy/power density nor the practical values reach the values of Li cathodes. Poorer performance is expected owing to larger size, larger mass, and lower cell voltage. Nonetheless, sodium ion batteries are considered to be practically relevant in view of the abundance of the element Na. The arguments in favor of Li and to the disadvantage of Na would be completely obsolete if the specific performance data of the latter would match the first. Here we present a cathode consisting of carbon-coated nanosized Na3V2(PO4)3 embedded in a porous carbon matrix, which not only matches but even outshines lithium cathodes under high rate conditions. It can be (dis)charged in 6 s with a current density as high as 22 A/g (200 C), still delivering a specific capacity of 44 mAh/g, while up to 20 C, the polarization is completely negligible.

Polyanion‐Type Electrode Materials for Sodium‐Ion Batteries

“…k) Facile soft chemistry‐based double carbon‐embedding approach for (C@NVP)@pC. Reproduced with permission 135. Copyright 2014, American Chemical Society.…”

Phosphate Framework Electrode Materials for Sodium Ion Batteries

“…Recently, the use of hierarchical carbon to decorate the Na 3 V 2 (PO 4 ) 3 electrode has been widely adopted to make high‐performance Na 3 V 2 (PO 4 ) 3 electrodes 11, 12, 60, 105, 111, 112, 113, 114, 115, 116. Zhu et al reported a carbon‐coated Na 3 V 2 (PO 4 ) 3 embedded in porous carbon with remarkable rate capability of 44 mAh g –1 at a current rate of 200 C ( Figure 6 d) 114.…”

“…Zhu et al reported a carbon‐coated Na 3 V 2 (PO 4 ) 3 embedded in porous carbon with remarkable rate capability of 44 mAh g –1 at a current rate of 200 C ( Figure 6 d) 114. Xu et al have also synthesized a layer‐by‐layer Na 3 V 2 (PO 4 ) 3 @rGO material with ≈3% rGO and 0.5% amorphous carbon, which shows excellent rate capability (41 mAh g –1 at a current rate of 200 C) and cyclability (70.0% capacity retention after 15 000 cycles at 50 C) 112.…”

“…Copyright 2015, Wiley‐VCH. (b,d) Reproduced with permission 114. Copyright 2014, American Chemical Society.…”

Sulfur‐Doped Carbon with Enlarged Interlayer Distance as a High‐Performance Anode Material for Sodium‐Ion Batteries

“…To promote the practical application of the SIB technology, it is urgent to explore new host materials for Na + ions. A number of transition metal oxides, poly‐anionic, and Prussian blue compounds have been identified as promising cathode materials for SIBs 3. Meanwhile, the choices for anodes seem limited:4 only a few materials such as disordered carbons, Ti‐based intercalation compounds, a few metal alloys, oxides, and sulfides have displayed satisfactory Na + ‐ion storage capacities, among which low crystalline hard carbons are the most attractive ones for commercial application of SIBs due to their low price.…”