The First Report on Excellent Cycling Stability and Superior Rate Capability of Na₃V₂(PO₄)₃ for Sodium Ion Batteries

Abstract

Sodium ion batteries are attractive for the rapidly emerging large‐scale energy storage market for intermittent renewable resources. Currently a viable cathode material does not exist for practical non‐aqueous sodium ion battery applications. Here we disclose a high performance, durable electrode material based on the 3D NASICON framework. Porous Na3V2(PO4)3/C was synthesized using a novel solution‐based approach. This material, as a cathode, is capable of delivering an energy storage capacity of ∼400 mWh/g vs. sodium metal. Furthermore, at high current rates (10, 20 and 40 C), it displayed remarkable capacity retention. Equally impressive is the long term cycle life. Nearly 50% of the initial capacity was retained after 30,000 charge/discharge cycles at 40 C (4.7 A/g). Notably, coulombic efficiency was 99.68% (average) over the course of cycling. To the best of our knowledge, the combination of high energy density, high power density and ultra long cycle life demonstrated here has never been reported before for sodium ion batteries. We believe our findings will have profound implications for developing large‐scale energy storage systems for renewable energy sources.

Anionic redox chemistry in Na-rich Na 2 Ru 1−y Sn y O 3 positive electrode material for Na-ion batteries

“…Like their Li-analogue, Na 2 Ru 1−y Sn y O 3 shows capacities that exceed theoretical capacity calculated from the cationic redox species. The high capacity was found, by means of XPS analysis, to be associated to the accumulation of both cationic (Ru ) redox processes.…”

High-capacity antimony sulphide nanoparticle-decorated graphene composite as anode for sodium-ion batteries

“…With optimization, the first cycle efficiency can be improved and we expect the energy density can be increased to 100 Wh kg À 1 . In addition, if other cathode material such as Na 3 V 2 (PO 4 ) 2 F 3 28 , Na 3 V 2 (PO 4 ) 3 29 or NaFe 0.5 Co 0.5 O 2 30 , with capacity 4115 mAh g À 1 is used, energy density could be further increased to 4150 Wh kg À 1 by reducing the amount of cathode materials. For comparison, a LiFePO 4 -Li 4 Ti 5 O 12 LIB system has a voltage of 1.9 V, in which cathode and anode contribute about 150 mAh g À 1 each.…”

Role of intermediate phase for stable cycling of Na 7 V 4 (P 2 O 7 ) 4 PO 4 in sodium ion battery

“…As another example, the vanadium-based NASICON structure Na 3 V 2 (PO 4 ) 3 exhibits a single plateau without intermediate phases at low current rates; however, it shows a peak split at high current rates, as in the VODP (40). In the fast charge/discharge conditions, thermodynamically inaccessible intermediate phases in slow rates can be viable owing to the increased polarizations.…”