Title: Scalable Synthesis of Defect Abundant Si Nanorods for High-Performance Li-Ion Battery Anodes

Abstract

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 Al ₂O ₃ solid electrolyte interphase (SEI) on the Si surface, and the low surface area (31 mmore » ² 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.« less

Authors:

Wang, Jing ^[1]; Meng, Xiangcai ^[1]; Fan, Xiulin ^[2]; Zhang, Wenbo ^[1]; Zhang, Hongyong ^[1]; Wang, Chunsheng ^[2]

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+ Show Author Affiliations

1. Jiamusi Univ. (China). School of Materials Science and Engineering
2. Univ. of Maryland, College Park, MD (United States). Dept. of Chemical and Biomolecular Engineering

Publication Date:

2015-05-26

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Nanostructures for Electrical Energy Storage (NEES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NNSFC)

OSTI Identifier:

1386081

Grant/Contract Number:  

SC0001160; 31100687

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

ACS Nano

Additional Journal Information:

Journal Volume: 9; Journal 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; Journal ID: ISSN 1936-0851

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; lithium-ion battery; silicon anode; eutectic Al−Si ingot; PDA self-polymerization; Bio-inspired; Energy storage (including batteries and capacitors); Defects; Charge transport; Synthesis (novel materials); Synthesis (self-assembly); Synthesis (scalable processing)