Graphene coating on silicon anodes enabled by thermal surface modification for high-energy lithium-ion batteries

Journal Article · 24 February 2022 · MRS Bulletin

DOI: https://doi.org/10.1557/s43577-021-00191-4 · OSTI ID:1867424

Kim, Sang Cheol ^[1]; Huang, William ^[1]; Zhang, Zewen ^[1]; Wang, Jiangyan ^[1]; Kim, Yongseok ^[2]; Jeong, You Kyeong ^[1]; Oyakhire, Solomon T. ^[1]; Yang, Yufei ^[1]; Cui, Yi ^[3]

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1. Stanford Univ., CA (United States)
2. Stanford Univ., CA (United States); Samsung SDI (Korea, Republic of)
3. Stanford Univ., CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES)

Silicon is a high-energy density anode material for lithium-ion batteries, but it possesses shortcomings such as poor electronic conductivity, interfacial instability and mechanical fracturing that hinder its battery cycling. Carbon coating has been an important strategy for stabilizing silicon anodes, but the effects of the silicon surface properties on carbon coating morphology and the consequent silicon cycling stability have not been clearly elucidated. Herein, we find that thermal oxidation of the silicon anodes followed by chemical vapor deposition of carbonaceous precursors leads to a well-ordered graphene coating, whereas disordered graphite coating is formed on the native silicon surface. Graphene-coated silicon exhibits superior cycling performance, retaining a discharge capacity of ~1300 mAh g^-1 after 300 cycles, whereas the disordered graphite-coated silicon suffers continuous degradation, retaining only~600 mAh g^-1 after 300 cycles. Cryogenic electron microscopy reveals the mechanism behind the difference in cycling stabilities; graphene coated silicon is able to withstand the large mechanical strains induced during extended cycling, whereas disordered graphite coating is ruptured, exposing silicon surfaces to the electrolyte, leading to extensive buildup of SEI and poor cycling performance. Characterization of the silicon surface reveals that thermal treatment yields an oxygen-rich surface layer, which is hypothesized to play a decisive role in dictating the carbon coating. This work highlights the effect of silicon surface properties on carbon coating microstructure, and presents thermal treatment as a facile avenue to attain graphene coating on silicon anodes.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1867424
• Journal Information: MRS Bulletin, Journal Name: MRS Bulletin Journal Issue: 2 Vol. 47; ISSN 0883-7694
• Publisher: Materials Research SocietyCopyright Statement
• Country of Publication: United States
• Language: English