Synthesis and electrochemical characterization of anode material with titanium-silicon alloy solid core/nanoporous silicon shell structures for lithium rechargeable batteries

초록

Composite materials composed of titanium silicon alloy (Ti-Si alloy) core and porous Si shell (core -shell (C/S) composite) are prepared, and their electrochemical performance as anode materials for lithium-ion batteries is reported. The C/S composites are fabricated by selective etching of the titanium suicide phase in the surface region of a Ti-Si alloy that consists of titanium suicide and Si phases. The Ti Si alloy is mechanically alloyed (MA) by ball-milling a mixture containing elemental Si and TiH2. Prior to the etching treatment, some of the MA samples are annealed at temperatures ranging from 600 to 800 degrees C to further develop the crystalline structure; annealing leads to the increase in the crystallite size of the Si and silicide phases. Thereby, the core and shell structure of the C/S composites and their electrochemical behaviors are controlled. Electrodes prepared by blending the C/S composites with graphite show good cycle performance and rate capability. (C) 2015 Elsevier B.V. All rights reserved.

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