Cu3Si-doped porous-silicon particles prepared by simplified chemical vapor deposition method as anode material for high-rate and long-cycle lithium-ion batteries

• Published in: Journal of alloys and compounds Vol. 701; pp. 425 - 432
• Main Authors: Woo, Jae-Young, Kim, A-Young, Kim, Min Kyu, Lee, Sang-Hyup, Sun, Yang-Kook, Liu, Guicheng, Lee, Joong Kee
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.04.2017
• Subjects: Anode material; Cu3Si doping; Lithium-ion batteries; Porous silicon particles; Simplified CVD method; Simplified CVD method; Lithium-ion batteries; Anode material; Porous silicon particles; Cu3Si doping
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.01.137

To provide a possible proposal for the large-scale production of a high performance silicon-based anode material in the lithium battery industry, a Cu3Si nanoparticle doped porous-silicon particles was prepared via a simplified chemical vapor deposition (CVD) process and heat treatment for the first time. In this work, the Cu3Si doping content was optimized by discharge/charge, transmission electron microscopy and electrochemical impedance spectroscopy tests. The results show that compared with the porous-silicon (PS) particles, the Cu3Si doping significantly enhanced the discharge capacity, coulombic efficiency, capacity retention, and high-rate performance of the silicon-based anode. The optimum performance with a discharge capacity of 3036.4 mA h g−1 and a coulombic efficiency of 90.49% at the first cycle (after the first three formation cycles) and a capacity retention of 58.72% after 100 cycles occurred at a Cu3Si doping content of 2 wt%. The reasons for this are as follows: the PS particles with a similarly silicon nanorod structure accommodated the volume change to maintain the mechanical stability of the electrode during the cycling process; during the simplified CVD process, the nanostructure of silicon was retained; the high conductivity due to Cu3Si doping decreased the formation resistance of the solid-electrolyte interphase (SEI) film and enhanced the diffusion coefficient of Li+ inside the silicon-based material; both fewer Cu3Si doping and aggregation particles resulting from excessive Cu3Si doping yielded insufficient electrical conductivity and decreased the formation resistance of the SEI film for the silicon-based material. •Using simplified CVD process for promoting mass production of Cu3Si doped porous Si material.•Si nanorods accommodate volume change to maintain stability of anode during cycling.•High conductivity caused by Cu3Si doping decreases formation resistance of SEI film.•PS with uniform 2 wt% Cu3Si doping possesses the highest performance.