Ultrafast electrochemical lithiation of individual Si nanowire anodes

Xiao Hua Liu, Li Qiang Zhang, Li Zhong, Yang Liu, He Zheng, Jiang Wei Wang, Jeong Hyun Cho, Shadi A. Dayeh, S. Tom Picraux, John P. Sullivan, Scott X. Mao, Zhi Zhen Ye, Jian Yu Huang

Research output: Contribution to journalArticlepeer-review

309 Scopus citations

Abstract

Using advanced in situ transmission electron microscopy, we show that the addition of a carbon coating combined with heavy doping leads to record-high charging rates in silicon nanowires. The carbon coating and phosphorus doping each resulted in a 2 to 3 orders of magnitude increase in electrical conductivity of the nanowires that, in turn, resulted in a 1 order of magnitude increase in charging rate. In addition, electrochemical solid-state amorphization (ESA) and inverse ESA were directly observed and characterized during a two-step phase transformation process during lithiation: crystalline silicon (Si) transforming to amorphous lithium - silicon (LixSi) which transforms to crystalline Li15Si4 (capacity 3579 mAhg-1). The ultrafast charging rate is attributed to the nanoscale diffusion length and the improved electron and ion transport. These results provide important insight in how to use Si as a high energy density and high power density anode in lithium ion batteries for electrical vehicle and other electronic power source applications.

Original languageEnglish (US)
Pages (from-to)2251-2258
Number of pages8
JournalNano letters
Volume11
Issue number6
DOIs
StatePublished - Jun 8 2011

Keywords

  • Silicon nanowire
  • carbon coating
  • doping
  • fast lithiation
  • lithium ion battery

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