期刊
JOURNAL OF MATERIALS CHEMISTRY A
卷 6, 期 45, 页码 22790-22797出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c8ta07662f
关键词
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资金
- Royal Academy of Engineering
- National Key RAMP
- D Program of China [2016YFA0202602]
- National Natural Science Foundation of China [U1663225, 21671155]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT_15R52]
- Fundamental Research Funds for the Central Universities [WUT: 2017III001]
Sodium-selenium (Na-Se) batteries are a promising substitute for traditional Li-ion batteries due to their high theoretical volumetric capacity (approximate to 3260 mA h cm(-3)). However, shuttle effects and large volume changes still limit their practical applications. Herein, we embed Se clusters in nitrogen-doped hierarchically radial-structured microporous carbon (N-HRMC) derived from a zinc-glutamate metal-organic framework (MOF) for advanced sodium storage. In this carbon-based composite, the micropores and the C-Se and C-O-Se bonds in N-HRMC effectively confine the Se clusters and Na2Se during the discharge-charge process. The nitrogen doping in N-HRMC strongly enhances the electrical conductivity of Se and chemical adsorption on Na2Se. In particular, density functional theory (DFT) calculations demonstrate that pyridinic-N atoms provide much more chemical adsorption of Na2Se than graphitic-N and pyrrolic-N atoms. Consequently, the cathode with Se clusters embedded in N-HRMC deliver a capacity of 612 mA h g(-1) after 200 cycles at 0.2C, with cycling stability for >500 cycles and a capacity retention of approximate to 100% from the 20(th) cycle at 0.5C, representing one of the best reported results for Na-Se batteries. Our work here suggests that embedding Se clusters in nitrogen-doped hierarchically structured microporous carbon systems presents an attractive strategy to enhance the capacity and rate capability of Na-Se batteries.
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