High-rate, ultralong cycle-life lithium/sulfur batteries enabled by nitrogen-doped graphene.
Nano Lett
; 14(8): 4821-7, 2014 Aug 13.
Article
en En
| MEDLINE
| ID: mdl-25073059
ABSTRACT
Nitrogen-doped graphene (NG) is a promising conductive matrix material for fabricating high-performance Li/S batteries. Here we report a simple, low-cost, and scalable method to prepare an additive-free nanocomposite cathode in which sulfur nanoparticles are wrapped inside the NG sheets (S@NG). We show that the Li/S@NG can deliver high specific discharge capacities at high rates, that is, â¼ 1167 mAh g(-1) at 0.2 C, â¼ 1058 mAh g(-1) at 0.5 C, â¼ 971 mAh g(-1) at 1 C, â¼ 802 mAh g(-1) at 2 C, and â¼ 606 mAh g(-1) at 5 C. The cells also demonstrate an ultralong cycle life exceeding 2000 cycles and an extremely low capacity-decay rate (0.028% per cycle), which is among the best performance demonstrated so far for Li/S cells. Furthermore, the S@NG cathode can be cycled with an excellent Coulombic efficiency of above 97% after 2000 cycles. With a high active S content (60%) in the total electrode weight, the S@NG cathode could provide a specific energy that is competitive to the state-of-the-art Li-ion cells even after 2000 cycles. The X-ray spectroscopic analysis and ab initio calculation results indicate that the excellent performance can be attributed to the well-restored C-C lattice and the unique lithium polysulfide binding capability of the N functional groups in the NG sheets. The results indicate that the S@NG nanocomposite based Li/S cells have a great potential to replace the current Li-ion batteries.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Nano Lett
Año:
2014
Tipo del documento:
Article
País de afiliación:
China