Fabrication of multi-shell coated silicon nanoparticles via in-situ electroless deposition as high performance anodes for lithium ion batteries

Si-based materials have been extensively studied because of their high theoretical capacity, low working potential, and abundant reserves, but serious initial irreversible capacity loss and poor cyclic performance resulting from large volume change of Si during lithiation and delithiation processes restrict their widespread application. Herein, we report the preparation of multi-shell coated Si (DS-Si) nanocomposites by in-situ electroless deposition method using Si granules as the active materials and copper sulfate as Cu sources. The ratio of Si and Cu was readily tuned by varying the concentration of copper sulfate. The multi-shell (Cu@CuxSi/SiO2) coating on Si surface promotes the formation of robust and dense SEI films and the transportation of electron. Thus, the obtained DS-Si composites exhibit an initial coulombic efficiency of 86.2%, a capacity of 1636 mAh g(-1) after 100 discharge-charge cycles at 840 mA g(-1), and an average charge capacity of 1493 mAh g(-1) at 4200 mA g(-1). This study provides a low-cost and large-scale approach to the preparation of nanostructured Si-metal composites anodes with good electrochemical performance for lithium ion batteries. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.