Electron-rich driven electrochemical solid-state amorphization in Li-Si alloys.
The physical and chemical behaviors of materials used in energy storage devices, such as lithium-ion batteries (LIBs), are mainly controlled by an electrochemical process, which normally involves insertion/extraction of ions into/from a host lattice with a concurrent flow of electrons to compensate charge balance. The fundamental physics and chemistry governing the behavior of materials in response to the ions insertion/extraction is not known. Herein, a combination of in situ lithiation experiments and large-scale ab initio molecular dynamics simulations are performed to explore the mechanisms of the electrochemically driven solid-state amorphization in Li-Si systems. We find that local electron-rich condition governs the electrochemically driven solid-state amorphization of Li-Si alloys. This discovery provides the fundamental explanation of why lithium insertion in semiconductor and insulators leads to amorphization, whereas in metals, it leads to a crystalline alloy. The present work correlates electrochemically driven reactions with ion insertion, electron transfer, lattice stability, and phase equilibrium.
Department of Applied Physics, University of Electronic Science and Technology of China , Chengdu, 610054, P. R. China.
Zhiguo
Z
Wang
Meng
M
Gu
Yungang
Y
Zhou
Xiaotao
X
Zu
Justin G
JG
Connell
Jie
J
Xiao
Daniel
D
Perea
Lincoln J
LJ
Lauhon
Junhyeok
J
Bang
Shengbai
S
Zhang
Chongmin
C
Wang
Fei
F
Gao
D000497:Alloys; D011211:Electric Power Supplies; D004583:Electrons; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D044367:Phase Transition; D012825:Silicon / Q000737:chemistry*
D000497:Alloys; D007477:Ions; D008094:Lithium; D012825:Silicon