期刊
CHEMICAL ENGINEERING JOURNAL
卷 461, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2023.141957
关键词
Antimony telluride; Potassium-ion batteries; Anode materials; Conversion-alloying mechanism
Nanoplate-structured Sb2Te3 anchored on graphene and N-doped C (Sb2Te3@rGO@NC) is used as an anode material for potassium-ion batteries, exhibiting a dual encapsulation effect that can effectively restrain large volume expansion and enhance electronic transfer and ion adsorption. The resulting Sb2Te3@rGO@NC electrode delivers high charge capacity, rate capability, and long-term lifetime, demonstrating the potential of Sb2Te3-based anodes for potassium-ion batteries and providing insights into the K-ion storage mechanism.
Anode materials with conversion-alloying dual mechanism are crucial for the development of high energy density potassium-ion batteries (PIBs), while large volume expansion and poor dynamic behavior hinder its development. Herein, nanoplate-structured Sb2Te3 anchored on graphene and N-doped C (Sb2Te3@rGO@NC) is regarded as anode material for PIBs for the first time. The dual encapsulation effect of Sb2Te3@rGO@NC composite with strong chemical bonding of Sb-C can not only significantly restrain the large volume expansion to maintain the electrode integrity, but also efficiently enhance the electronic transfer, K-ion adsorption and diffusion ability, verified by first principles calculations and electrochemical kinetics study. As a result, the resultant Sb2Te3@rGO@NC electrode delivers a high initial charge specific capacity of 384.9 mAh.g(-1) at 50 mA.g(-1), great rate capability and long-term lifetime over 200 cycles at 200 mA.g(-1). Ex situ TEM and XPS results clarify that the electrode undergoes typical conversion-alloying dual-mechanisms with 12 mol K-ion transfer per formula employing Sb-ion as redox site (Sb2Te3 + 12 K+ + 12e(-) <-> 3K(2)Te + 2K(3)Sb). This work could pave the way for the fast development of Sb2Te3-based anode for PIBs, and help to understand the K-ion storage mechanism.
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