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Healable Structure Triggered by Thermal/Electrochemical Force in Layered GeSe 2 for High Performance Li‐Ion Batteries
Author(s) -
Wei Yaqing,
Huang Liang,
He Jun,
Guo Yanpeng,
Qin Ruihuan,
Li Huiqiao,
Zhai Tianyou
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201703635
Subject(s) - materials science , amorphous solid , electrochemistry , electronegativity , polarization (electrochemistry) , chemical engineering , ion , chemical physics , nanotechnology , crystallography , chemistry , electrode , physics , quantum mechanics , engineering
Abstract 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 GeSe 2 and its carbon composite are synthesized by high‐energy ball milling and it is surprisingly found that crystalline c‐GeSe 2 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 MX 2 (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 GeSe 2 . Similarly, electrochemical delithium force also triggers the rebuilding of GeSe bonding upon Li‐extraction, boosting GeSe 2 /C with large capacity (1050 mA h g −1 ), ultrahigh ICE (94%), and cycling stability.