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Cu 9 S 5 Nanoflower Cathode for Mg Secondary Batteries: High Performance and Reaction Mechanism
Author(s) -
Wu Mengyi,
Zhang Yujie,
Wu Hao,
Qin Aiqiong,
Li Xue,
Shen Jingwei,
Chen Zhongxue,
Cao Shunan,
Li Ting,
Xu Fei
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201800777
Subject(s) - nanoflower , cathode , polysulfide , electrolyte , dissolution , copper sulfide , copper , materials science , chemical engineering , battery (electricity) , diffusion , sulfide , energy storage , nanotechnology , electrode , chemistry , metallurgy , nanostructure , power (physics) , physics , quantum mechanics , engineering , thermodynamics
Mg secondary batteries have attracted widespread attention as a promising large‐scale energy storage system with high safety and high natural abundance, but their development is hindered by the limited cathode materials. Herein, a Cu 9 S 5 nanoflower as a high‐performance conversion cathode for Mg secondary batteries is reported. This material delivers a reversible capacity of 200 mAh g −1 at 20 mA g −1 , a good rate capability of 90 mAh g −1 at 1000 mA g −1 , and a superior long‐term cycleability over 400 cycles. The reversible conversion reaction mainly occurs between Cu 1.96 S and Cu/MgS. Significantly, the outstanding performance is ascribed to the moderate dissolution of the copper polysulfide intermediate in the electrolyte, which substitutes a fast liquid‐phase copper ion diffusion for the sluggish solid‐phase Mg 2+ ion diffusion, and thus facilitates the reaction kinetics. A scientific insight into the abnormally high performance of copper sulfide as a Mg battery cathode and a significant hint for the performance enhancement of Mg‐S batteries are provided.