Ultrafast lithium storage of high dispersed silicon and titanium oxide nanoparticles in carbon

Abstract

Silicon and carbon composites as an anode material in lithium-ion batteries are the most promising candidates to replace conventional graphite, owing to their synergetic effects of high capacity and excellent mechanical stability. Despite these appealing merits, the significant challenge is directly related to the poor dispersion of Si nanoparticles in the carbon nanofiber (CNF) matrix, leading to a structural collapse after cycling due to the large volume change (similar to 300%) of Si. Thus, we synthesized unique composites of high-dispersed Si and titanium oxide (TiO2) nanoparticles in the CNF matrix (Si/TiO2/CNF) using the complexation of TiO2 nanoparticles in order to the high-dispersed Si nanoparticles. The Si/TiO2/CNF electrode presents enhanced electrochemical properties including excellent cycling stability and high specific capacity (947 mA h g(-1) at 100 mA g(-1) after 100 cycles), remarkable high-rate performance (612 mA h g(-1) at 2000 mA g(-1)), and outstanding ultrafast cycling stability (478 mA h g(-1) at 2000 mA g(-1) after 100 cycles). It is revealed that the high-dispersed Si nanoparticles can maintain the initial structure after cycling, which definitely demonstrates the superiority of our concept. (C) 2017 Elsevier B.V. All rights reserved.