121st General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code MAT.P-397
Subject Si@C yolk-shell structures with Improved Initial Coulombic Efficiency for Lithium-ion Batteries
Authors Min seok Kang, Won Cheol Yoo*
Department of Applied Chemistry, Hanyang University, Korea
Abstract As current electronic devices need more capacity and long-lived energy storage, new materials that possess more energy storage are of highly desirable. Silicon presents capacity of 3580 mAh/g as anode material for lithium-ion batteries (LIBs), of which capacity is much higher than the capacity (372 mAh/g) of current graphite anode; thus it has been believed as a next-generation anode material for LIBs. Silicon anode suffers from several technical issues, however, which are of severe volume change up to 400 % during cycling and low electric conductivity. In addition, at the first cycle, silicon reacts excessively with the electrolyte to generate solid-electrolyte interface layer (SEI layer) due to volume expansion, which reduce the coulombic efficiency (CE), eventually resulting in lower the capacity of the battery. Herein, we present the relationship between size of Si nanocrystal and the 1st CE using Si@C yolk-shell structure. The Si@C yolk-shell structure is prepared from SiO2@C composite via magnesiothermic reduction. To confirm the relationship between crystal size and initial CE, we control the crystal size of Si through additional aging process at high temperature. As a result, it was confirmed that the initial CE of Si@C was improved as the crystal size of Si increased.
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