Failure mechanisms of single-crystal silicon electrodes in lithium-ion batteries.
Long-term durability is a major obstacle limiting the widespread use of lithium-ion batteries in heavy-duty applications and others demanding extended lifetime. As one of the root causes of the degradation of battery performance, the electrode failure mechanisms are still unknown. In this paper, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lithiation/delithiation cycles, using electrochemical testing, microstructure characterization, fracture mechanics and finite element analysis. Anisotropic lithium invasion causes crack initiation perpendicular to the electrode surface, followed by growth through the electrode thickness. The low fracture energy of the lithiated/unlithiated silicon interface provides a weak microstructural path for crack deflection, accounting for the crack patterns and delamination observed after repeated cycling. On the basis of this physical understanding, we demonstrate how electrolyte additives can heal electrode cracks and provide strategies to enhance the fracture resistance in future lithium-ion batteries from surface chemical, electrochemical and material science perspectives.
Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Feifei
F
Shi
Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA.
Zhichao
Z
Song
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Philip N
PN
Ross
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Chemistry, University of California, Berkeley, California 94720, USA.
Gabor A
GA
Somorjai
Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Robert O
0000-0002-0501-6998
RO
Ritchie
Department of Mechanical Engineering, University of California, Berkeley, California 94720, USA.
Kyriakos
K
Komvopoulos