Electrochemical performance and interfacial investigation on Si composite anode for lithium ion batteries in full cell

JOURNAL OF POWER SOURCES

卷:359

Article

Shobukawa, Hitoshi^1,2  Alvarado, Judith^1,3  Yang, Yangyuchen^1,3  Meng, Ying Shirley¹ 

[1] Univ Calif San Diego, Dept NanoEngn, 9500 Gilman Dr, La Jolla, CA 92093 USA

[2] Asahi Kasei, Corp Res & Dev Ctr, Chiyoda Ku, 1-105 Kanda Jinbocho, Tokyo 1018101, Japan

[3] Univ Calif San Diego, Mat Sci & Engn Program, La Jolla, CA 92093 USA

关键词: Lithium ion battery;    Silicon anode;    Full cell;    SEI;   

DOI  :  10.1016/j.jpowsour.2017.05.044

来源: Elsevier

【 摘 要 】

Lithium ion batteries (LIBs) containing silicon (Si) as a negative electrode have gained much attention recently because they deliver high energy density. However, the commercialization of LIBs with Si anode is limited due to the unstable electrochemical performance associated with expansion and contraction during electrochemical cycling. This study investigates the electrochemical performance and degradation mechanism of a full cell containing Si composite anode and LiFePO4 (lithium iron phosphate (LFP)) cathode. Enhanced electrochemical cycling performance is observed when the full cell is cycled with fluoroethylene carbonate (FEC) additive compared to the standard electrolyte. To understand the improvement in the electrochemical performance, x-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) are used. Based on the electrochemical behavior, FEC improves the reversibility of lithium ion diffusion into the solid electrolyte interphase (SEI) on the Si composite anode. Moreover, XPS analysis demonstrates that the SEI composition generated from the addition of FEC consists of a large amount of LiF and less carbonate species, which leads to better capacity retention over 40 cycles. The effective SEI successively yields more stable capacity retention and enhances the reversibility of lithium ion diffusion through the interphase of the Si anode, even at higher discharge rate. This study contributes to a basic comprehension of electrochemical performance and SEI formation of LIB full cells with a high loading Si composite anode. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

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