کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1287456 | 1497988 | 2013 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Electrochemical behaviors of nonstoichiometric silicon suboxides (SiOx) film prepared by reactive evaporation for lithium rechargeable batteries Electrochemical behaviors of nonstoichiometric silicon suboxides (SiOx) film prepared by reactive evaporation for lithium rechargeable batteries](/preview/png/1287456.png)
• The a-SiOx films prepared by reactive evaporation were studied as the anode.
• An electrochemical reaction between nonstoichiometric SiOx and Li was described.
• The a-SiOx (x = 1.02, 1.34) performed an excellent cyclability during 30 cycles.
• Crystallization of lithiated a-Si during cycle did not occur at a-SiOx (x = 1.02, 1.34).
We investigated the electrochemical behaviors of nonstoichiometric silicon suboxides (SiOx, for x = 0.17–1.34) as the anode material for lithium rechargeable batteries. The amorphous SiOx (a-SiOx) films were synthesized by reactive evaporation of Si with oxygen gas. The initial charge (lithiation) and discharge (delithiation) capacities were strongly related to the value of x in SiOx. We proposed an electrochemical reaction model of SiOx with lithium (Li) to describe the relationships quantitatively by assuming SiOx was composed of a reversible Si and an irreversible SiO2 component. Lithiated products were identified by XPS as a fully lithiated Si, Li2O, Li silicates (Li4SiO4, Li2SiO3), and SiO2. After discharge, a portion of the Li in Li–Si was found to remain undischargeable as LizSi (z; the function of x). This was an additional factor of the irreversible capacity. Peak positions assigned to LizSi in XPS Si2p spectra suggest that the value of z depends on the value of x. The a-SiOx (for x = 1.02, 1.34) films demonstrated excellent cyclability at a range of 0.005–1.5 V vs. Li/Li+. Absence of peaks at 0.45 V in differential capacity vs. voltage (dQ/dV) profiles indicates the suppression of crystallization of lithiated a-Si, even under deep cycle conditions.
Journal: Journal of Power Sources - Volume 244, 15 December 2013, Pages 149–157