Cu3P Binary Phosphide: Synthesis via a Wet Mechanochemical Method and Electrochemical Behavior as Negative Electrode Material for Lithium-Ion Batteries

• Published in: Advanced energy materials 2013-02, Vol.3 (2), p.231-238
• Main Authors: Stan, Marian Cristian, Klöpsch, Richard, Bhaskar, Aiswarya, Li, Jie, Passerini, Stefano, Winter, Martin
• Format: Article
• Language: English
• Subjects: Cu3P; cycling stability; Electrodes; Lithium; lithium-ion battery; mechanochemical synthesis; negative electrode; rate performance
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201200655

Mechanochemical synthesis of Cu3P in the presence of n‐dodecane results in a material with a secondary particle size distribution of 10 μm, secondary particles which consist of homogeneously agglomerated 20 nm primary particles. The electrochemical performance of Cu3P with lithium is influenced by the reaction depth, in other words by the lower potential cut‐off. During the electrochemical reaction, the displacement of copper by lithium from the Cu3P structure until the formation of Li3P and Cu deteriorates the capacity retention. Improved performance was obtained when the charge potential was limited to 0.50 V (vs. Li/Li+) and the formation of the LixCu3‐xP phase (0 ≤ × ≤ 2). In this case, when the potential is limited to 0.5 V, the capacity is stable for more than 50 cycles. Acceptable electrochemical performances in Li‐ion cells within the voltage range 0.50–2.0 V (vs. Li/Li+) were shown when Cu3P was used as an anode and Li1.2(Ni0.13Mn0.54Co0.13)O2 and LiNi0.5Mn1.5O4 as positive electrode materials. Increasing the current density of the Cu3P electrode material during the C‐rate test results in an increase of the voltage hysteresis. Furthermore, limiting the lower cut‐off potential to 0.50 V versus Li/Li+ improves both cycling and the C‐rate performance as compared to the case when the Cu3P electrode material is charged to 0.02 V versus Li/Li+.