Scalable Synthesis of Defect Abundant Si Nanorods for High-Performance Li-Ion Battery Anodes
- Jiamusi Univ. (China). School of Materials Science and Engineering
- Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering
Microsized nanostructured silicon–carbon composite is a promising anode material for high energy Li-ion batteries. However, large-scale synthesis of high-performance nano-Si materials at a low cost still remains a significant challenge. Here we report a scalable low cost method to synthesize Al/Na-doped and defect-abundant Si nanorods that have excellent electrochemical performance with high first-cycle Coulombic efficiency (90%). The unique Si nanorods are synthesized by acid etching the refined and rapidly solidified eutectic Al–Si ingot. To maintain the high electronic conductivity, a thin layer of carbon is then coated on the Si nanorods by carbonization of self-polymerized polydopamine (PDA) at 800 °C. The carbon coated Si nanorods (Si@C) electrode at 0.9 mg cm–2 loading (corresponding to area-specific-capacity of ~2.0 mAh cm–2) exhibits a reversible capacity of ~2200 mAh g–1 at 100 mA g–1 current, and maintains ~700 mAh g–1 over 1000 cycles at 1000 mA g–1 with a capacity decay rate of 0.02% per cycle. High Coulombic efficiencies of 87% in the first cycle and ~99.7% after 5 cycles are achieved due to the formation of an artificial Al2O3 solid electrolyte interphase (SEI) on the Si surface, and the low surface area (31 m2 g–1), which has never been reported before for nano-Si anodes. The excellent electrochemical performance results from the massive defects (twins, stacking faults, dislocations) and Al/Na doping in Si nanorods induced by rapid solidification and Na salt modifications; this greatly enhances the robustness of Si from the volume changes and alleviates the mechanical stress/strain of the Si nanorods during the lithium insertion/extraction process. Introducing massive defects and Al/Na doping in eutectic Si nanorods for Li-ion battery anodes is unexplored territory. We venture this uncharted territory to commercialize this nanostructured Si anode for the next generation of Li-ion batteries.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Nanostructures for Electrical Energy Storage (NEES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC)
- Grant/Contract Number:
- SC0001160; 31100687
- OSTI ID:
- 1386081
- Journal Information:
- ACS Nano, Vol. 9, Issue 6; Related Information: NEES partners with University of Maryland (lead); University of California, Irvine; University of Florida; Los Alamos National Laboratory; Sandia National Laboratories; Yale University; ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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