Enhanced reversibility and electrochemical performances of mechanically alloyed Cu 3 P achieved by Fe addition

• Published in: RSC advances 2016, Vol.6 (32), p.26800-26808
• Main Authors: Zhou, Aijun, Yang, Bin, Wang, Weihang, Dai, Xinyi, Zhao, Mingjuan, Xue, Jing, Han, Mangui, Fan, Cong, Li, Jingze
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C6RA01637E

Cu 3 P is a potential anode material for lithium-ion batteries with its comparable gravimetric capacity, but several times higher volumetric capacity (4732 mA h cm −3 ) than graphite. However, the cycling stability of Cu 3 P is poor at low discharge potentials and high current densities. In this work, Fe addition is employed as a simple strategy to modulate the composition and phase constitution of Cu 3 P nanopowders synthesized by wet mechanical alloying, and thereby to tune the electrochemical performance of the anode. The addition of Fe results in a composite constitute containing Cu 3 P as the major phase and some other minor phases including Cu, α-Fe and FeP, which are combinationally determined by X-ray diffraction, energy dispersive X-ray spectroscopy and Mössbauer spectroscopy. Electrochemical tests reveal that both the cycling stability and the rate capability of the electrodes are improved by Fe addition. The Cu 3 P electrode with 10% Fe addition shows the best cell performance, with the capacity being remarkably improved by over 100%, from 82 mA h g −1 to 178 mA h g −1 after 50 cycles at 0.75C between 2.0 V and 0.5 V vs. Li/Li + . The improvement of the electrochemical performance is engendered by a synergetic effect of the microstructure change of the powders and the presence of Fe-related minor phases, leading to increased electronic conductivity as well as enhanced electrochemical reversibility of the electrode.