Pomegranate-like MoC@C composites as stable anode materials for lithium-ion batteries

By Qi, Jun; Shi, Zhangping; Li, Xiang; Gao, Boxu; Wang, Hui; Yang, Lichun; Tang, Yi; Zhu, Min
Published in Journal of Alloys and Compounds 2019

Abstract

Transition metal carbides serving as anode materials for lithium-ion batteries attract increasing attention owing to their high capacity and excellent conductivity. In this article, pomegranate-like granules assembled by carbon coated molybdenum carbide nanocrystallites (MoC@C) are fabricated through facile carburization of metal-organic framework precursor of trimesic acid Molybdenum (Mo3(BTC)2). The pomegranate-like structure not only offers short diffusion paths for Li+, but also relieves the volume variations during the Li+ insertion/extraction process. The size of MoC nanocrystallites and the content of carbon coating can be optimized by adjusting the carburization temperature. The optimal MoC@C-700 sample exhibits superior cycle stability and high-rate performance. At 200 mA g?1, it shows reversible capacity of 647.3 mAh g?1. Even when the current density increases to 1 A g?1, it still delivers 570.6 mAh g?1 in the first cycle and maintains 509.8 mAh g?1 after 500 cycles. The high capacity and stable cycling performance indicate the pomegranate-like MoC@C composites may be promising for high-performance lithium-ion batteries anode.

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