Minimized Volume Expansion in Hierarchical Porous Silicon upon Lithiation
Journal Article
·
· ACS Applied Materials and Interfaces
- Pennsylvania State Univ., University Park, PA (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Kwangwoon Univ., Seoul (Korea, Republic of)
Silicon (Si) remains one of the most promising anode materials for next-generation lithium-ion batteries (LIBs). The key challenge for Si anodes is the huge volume change during lithiation-delithiation cycles that leads to electrode pulverization and rapid capacity fading. Here, we report a hierarchical porous Si (hp-Si) with a tailored porous structure [tunable primary pores (20-200 nm) and secondary nanopores (~3-10 nm)] that can effectively minimize the volume expansion. An in situ transmission electron microscopy (TEM) study revealed that the hp-Si material with the same porosity but larger primary pores can more effectively accommodate lithiation-induced volume expansion, giving rise to a much reduced apparent volume expansion on both material and electrode levels. Chemomechanical modeling revealed that because of the different relative stiffnesses of the lithiated and unlithiated Si phases, the primary pore size plays a key role in accommodating the volume expansion of lithiated Si. The higher structural stability of the hp-Si materials with larger primary pores also maintains the fast diffusion channels of the connective pores, giving rise to better power capability and capacity retention upon electrochemical cycling. Our findings point toward an optimized hp-Si material with minimal volume change during electrochemical cycling for next-generation LIBs.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1909181
- Report Number(s):
- PNNL-SA-162078
- Journal Information:
- ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Journal Issue: 14 Vol. 11; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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