Influence of Shell on the Electrochemical Properties of Si Nanoparticle
Si 나노입자에서 shell이 전기화학적 특성에 미치는 영향

Jeong-eun Lee, Jeong-boon Koo, Bo-yun Jang, Sung-Soo Kim
2016 Journal of the Korean Institute of Electrical and Electronic Material Engineers  
Effects of SiO x or C shells on electrochemical properties of Si nanoparticles were investigated. SiO x shells with thickness of 10~15 nm were formed on homogeneously crystalline Si nanoparticles. Incase of Si-C nanoparticles, there were 30~40 layers of C with a number of defects. Li-ion batteries were fabricated with the above-mentioned nanoparticles, and their electrochemical properties were measured. Pristine Si shows a high IRC (initial reversible capacity) of 2,517 mAh/g and ICE (initial
more » ... and ICE (initial columbic efficiency) of 87%, but low capacity retention of 22%, respectively. SiO x shells decreased IRC (1,534 mAh/g) and ICE (54%), while the retention increased up to 65%, which can be explained by irreversible phases such as LiO 2 and Li 2 SiO 3 . C shells exhibited no differences in IRC and ICE compared to the pristine Si but an enhanced retention of 54%, which might be from proper defect structures. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 새로운 음극 물질로서 가장 적합한 물질인 것으로 알려 졌다. 하지만, 리튬 이온을 물질 내로 삽입하는 과정에 서 발생되는 300%에 이르는 큰 부피 변화로 인해 활 물질의 분쇄(pulverization)가 발생하여 전극 수명 특 성이 급격히 저하되는 문제점을 가지고 있다 [2-6]. Si부피변화를 완화하기 위하여 Si 입자의 나노구조 화 [7], Si-C 복합체 이용 [8], Si과 비활성 혹은 활성 물질의 복합화 [9]등 다양한 연구가 진행 되고 있다. 특히, 다음과 같은 Core-Shell 구조를 이용한 활물질 제조와 Si-C 복합체에 관한 많은 연구가 진행되고 있다. Homma 등은 100 cycle에서 1,000 mAh/g 이상의 높 은 가역용량을 갖는 C 코팅된 Si-Core와 SiO x -Shell 나노입자를 PS-PVD (plasma spray physical vapor deposition)법을 이용하여 제조 보고한 바 있다 [10].
doi:10.4313/jkem.2016.29.4.255 fatcat:rl6x7pkjebh2vcyjvb37ald6c4