期刊
ADVANCED ENERGY MATERIALS
卷 8, 期 18, 页码 -出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/aenm.201703635
关键词
GeSe2; healable structures; high coulomb efficiencies; layered structures; lithium-ion batteries
类别
资金
- National Natural Science Foundation of China [21571073]
- Ministry of Science and Technology of the People's Republic of China [2015CB932600]
- Hubei Provincial Natural Science Foundation of China [2016CFA031]
- National Key Research and Development Program of Strategic Advanced Electronic Materials [2016YFB0401100]
- Shenzhen Science and Technology Project [JCYJ20170307154129933]
- Fundamental Research Funds for the Central University
The metal sulfide or selenides have attracted increasing attention for high-energy lithium-ion batteries due to their unique layer structure flexibility, higher conductivity, and lower voltage polarization than metal oxides. However, low initial coulomb efficiency (ICE), serious structure destruction, and irreversible bonding chemistry are still big challenges for their practical application. Herein, layer GeSe2 and its carbon composite are synthesized by high-energy ball milling and it is surprisingly found that crystalline c-GeSe2 possesses higher reversible capacity and better rate performances than their amorphous counterparts. More specially, the broken GeSe bondings upon lithiation are also observed to regenerate after delithiation. These unusual phenomena are investigated by both experimental tools and theoretical calculations. Compared to other typical MX2 (M = Mo, W, X = S, Se), the electronegativity of Ge is more close to selenium and the formation energy of GeSe bonding is much smaller. Thus, a mild driven force such as thermoheating at low temperature can recover the ordered layer structure, helping to heal the high conductivity and unimpeded Li diffusion pathways for crystalline GeSe2. Similarly, electrochemical delithium force also triggers the rebuilding of GeSe bonding upon Li-extraction, boosting GeSe2/C with large capacity (1050 mA h g(-1)), ultrahigh ICE (94%), and cycling stability.
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