Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 141, Issue 17, Pages 7014-7027Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jacs.9b01589
Keywords
-
Categories
Funding
- European Union's Horizon 2020 research and innovation program under the EU Marie Sklodowska-Curie [655444, 656870]
- Sony Corporation
- Engineering and Physical Sciences Research Council (EPSRC) [EP/P003532/1]
- German Research Foundation (DFG, Research Fellowship) [GR 5342/1-1]
- Sony Energy Devices Corporation educational program
- Marie Curie Actions (MSCA) [655444] Funding Source: Marie Curie Actions (MSCA)
- EPSRC [EP/P003532/1] Funding Source: UKRI
Ask authors/readers for more resources
Silicon monoxide is a promising alternative anode material due to its much higher capacity than graphite, and improved cyclability over other Si anodes. An in-depth analysis of the lithium silicide (LixSi) phases that form during lithiation/delithiation of SiO is presented here and the results are compared with pure-Si anodes. A series of anode materials is first prepared by heating amorphous silicon monoxide (a-SiO) at different temperatures, X-ray diffraction and Si-29 NMR analysis revealing that they comprise small Si domains that are surrounded by amorphous SiO2, the domain size and crystallinity growing with heat treatment. In and ex situ Li-7 and Si-29 solid-state NMR combined with detailed electrochemical analysis reveals that a characteristic metallic LixSi phase is formed on lithiating a-SiO with a relatively high Li concentration of x = 3.4-3.5, which is formed/decomposed through a continuous structural evolution involving amorphous phases differing in their degree of Si-Si connectivity. This structural evolution differs from that of pure-Si electrodes where the end member, crystalline Li15Si4, is formed/decomposed through a two-phase reaction. The reaction pathway of SiO depends, however, on the size of the ordered Si domains within the pristine material. When crystalline domains of >3 nm within a SiO2 matrix are present, a phase resembling Li15Si4 forms, albeit at a higher overpotential. The continuous formation/decomposition of amorphous LixSi phases without the hysteresis and phase change associated with the formation of c-Li15Si4, along with a partially electrochemically active SiO2/lithium silicate buffer layer, are paramount for the good cyclability of a-SiO.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available