期刊
ACS APPLIED MATERIALS & INTERFACES
卷 8, 期 1, 页码 197-207出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsami.5b08340
关键词
nitrogen-doped carbon; SnO2; Sn; three-dimensional graphene; lithium ion battery
资金
- National Natural Science Foundation of China [51502043, 21073241, 51276044, 51302042, 21176045, U1401246]
- Guangdong Province [U1401246]
- Natural Science Foundation of Guangdong Province of China [2014A030310382]
- Science and Technology Program of Guangdong Province of China [2014B010106005, 2015B010135011, 2015A050502047]
- Science and Technology Program of Guangzhou City of China [201508030018]
- Guangdong Province Science & Technology Bureau [2014A010106029]
- Major International (Regional) Joint Research Project [51210002]
- National Basic Research Program of China [2015CB932304]
- Pearl River New Star Plan of Science and Technology of Guangzhou City of China [2013J2200038]
A peculiar nanostructure consisting of nitrogen-doped, carbon-encapsulated (N-C) SnO2@Sn nanoparticles grafted on three-dimensional (3D) graphene-like networks (designated as N-C@SnO2@Sn/3D-GNs) has been fabricated via a low-cost and scalable method, namely an in situ hydrolysis of Sn salts and immobilization of SnO2 nanoparticles on the surface of 3D-GNs, followed by an in situ polymerization of dopamine on the surface of the SnO2/3D-GNs, and finally a carbonization. In the composites, three-layer core-shell N-C@SnO2@Sn nanoparticles were uniformly grafted onto the surfaces of 3D-GNs, which promotes highly efficient insertion/extraction of Li+. In addition, the outermost N-C layer with graphene-like structure of the N-C@SnO2@Sn nanoparticles can effectively buffer the large volume changes, enhance electronic conductivity, and prevent SnO2/Sn aggregation and pulverization during discharge/charge. The middle SnO2 layer can be changed into active Sn and nano-Li2O during discharge, as described by SnO2 + Li+ -> Sn + Li2O, whereas the thus-formed nano-Li2O can provide a facile environment for the alloying process and facilitate good cycling behavior, so as to further improve the cycling performance of the composite. The inner Sn layer with large theoretical capacity can guarantee high lithium storage in the composite. The 3D-GNs, with high electrical conductivity (1.50 x 103 S m(-1)), large surface area (1143 m(2) g(-1)), and high mechanical flexibility, tightly pin the core-shell structure of the N-C@SnO2@Sn nanoparticles and thus lead to remarkably enhanced electrical conductivity and structural integrity of the overall electrode. Consequently, this novel hybrid anode exhibits highly stable capacity of up to 901 mAh g(-1), with similar to 89.3% capacity retention after 200 cycles at 0.1 A g(-1) and superior high rate performance, as well as a long lifetime of 500 cycles with 84.0% retention at 1.0 A g(-1). Importantly, this unique hybrid design is expected to be extended to other alloy-type anode materials such as silicon, germanium, etc.
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