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Towards Highly Stable Storage of Sodium Ions: A Porous Na 3 V 2 (PO 4 ) 3 /C Cathode Material for Sodium‐Ion Batteries
Author(s) -
Shen Wei,
Wang Cong,
Liu Haimei,
Yang Wensheng
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201300005
Subject(s) - cathode , electrolyte , sodium , ion , porosity , materials science , current density , analytical chemistry (journal) , electrode , chemical engineering , chemistry , composite material , chromatography , metallurgy , physics , organic chemistry , quantum mechanics , engineering
A porous Na 3 V 2 (PO 4 ) 3 cathode material coated uniformly with a layer of approximately 6 nm carbon has been synthesized by the sol–gel method combined with a freeze‐drying process. The special porous morphology and structure significantly increases the specific surface area of the material, which greatly enlarges the contact area between the electrode and electrolyte, and consequently supplies more active sites for sodium ions. When employed as a cathode material of sodium‐ion batteries, this porous Na 3 V 2 (PO 4 ) 3 /C exhibits excellent rate performance and cycling stability; for instance, it shows quite a flat potential plateau at 3.4 V in the potential window of 2.7–4.0 V versus Na + /Na and delivers an initial capacity as high as 118.9 and 98.0 mA h g −1 at current rates of 0.05 and 0.5 C, respectively, and after 50 cycles, a good capacity retention of 92.7 and 93.6 % are maintained. Moreover, even when the discharge current density is increased to 5 C (590 mA g −1 ), an initial capacity of 97.6 mA h g −1 can still be achieved, and an exciting capacity retention of 88.6 % is obtained after 100 cycles. The good cycle performance, excellent rate capability, and moreover, the low cost of Na 3 V 2 (PO 4 ) 3 /C suggest that this material is a promising cathode for large‐scale sodium‐ion rechargeable batteries.