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Super Stable Antimony-carbon Composite Anodes for Potassium-ion Batteries

Abstract

Potassium-ion batteries (PIBs) have been considered as promising alternatives to lithium-ion batteries due to the high natural K abundance of 2.09 wt.% (vs. 0.0017 wt.% for Li) and low K/K+ redox potential of −2.93 V (vs. -2.71 V for Na/Na+). However, PIB electrodes still suffer huge challenges due to the large K-ion radius and slow reaction dynamics. Herein, we report a high-capacity Sb@CSN composite anode with Sb nanoparticles uniformly encapsulated by carbon sphere network (CSN) for PIBs. First-principles computations and electrochemical characterizations confirm a reversible sequential phase transformation of KSb2, KSb, K5Sb4, and K3Sb during potassiation/depotassiation process. In a concentrated 4M KTFSI/EC+DEC electrolyte, the Sb@CSN anode delivers a high reversible capacity of 551 mAh/g at 100 mA/g for 100 cycles with an extremely slow capacity decay of only 0.06% per cycle from the 10th to 100th cycling; when up to a high current density of 200 mA/g, Sb@CSN anode still maintains a capacity of 504 mAh/g for 220 cycles. The Sb@CSN anodes demonstrate one of the best electrochemical performances for all K-ion batteries anodes reported to date. The exceptional performances of Sb@CSN should be attributed to the efficient capsulation of small Sb nanoparticles into conductive carbon network as well as the formation of a robust KF-rich SEI layer on Sb@CSN anode in the concentrated 4M KTFSI/EC+DEC electrolyte.

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Publication details

The article was received on 27 Sep 2018, accepted on 08 Jan 2019 and first published on 08 Jan 2019


Article type: Paper
DOI: 10.1039/C8EE02836B
Citation: Energy Environ. Sci., 2019, Accepted Manuscript
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    Super Stable Antimony-carbon Composite Anodes for Potassium-ion Batteries

    J. Zheng, Y. Yang, X. Fan, G. Ji, X. Ji, H. Wang, S. Hou, M. Zachariah and C. Wang, Energy Environ. Sci., 2019, Accepted Manuscript , DOI: 10.1039/C8EE02836B

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