Hierarchical porous silicon structures with extraordinary mechanical strength as high-performance lithium-ion battery anodes

• Published in: Nature communications Vol. 11; no. 1; pp. 1474 - 9
• Main Authors: Jia, Haiping, Li, Xiaolin, Song, Junhua, Zhang, Xin, Luo, Langli, He, Yang, Li, Binsong, Cai, Yun, Hu, Shenyang, Xiao, Xingcheng, Wang, Chongmin, Rosso, Kevin M., Yi, Ran, Patel, Rajankumar, Zhang, Ji-Guang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.03.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638; 639/638/161; 639/638/161/891; Anodes; batteries; Calendering; Carbon; Cathodes; chemistry; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; ENERGY STORAGE; Flux density; Humanities and Social Sciences; Lithium; Lithium-ion batteries; Mechanical properties; Microspheres; multidisciplinary; Nanotubes; Porosity; Porous silicon; Rechargeable batteries; Retention; Science; Science (multidisciplinary); Silicon; Specific capacity; Strength; Structural hierarchy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-15217-9

Porous structured silicon has been regarded as a promising candidate to overcome pulverization of silicon-based anodes. However, poor mechanical strength of these porous particles has limited their volumetric energy density towards practical applications. Here we design and synthesize hierarchical carbon-nanotube@silicon@carbon microspheres with both high porosity and extraordinary mechanical strength (>200 MPa) and a low apparent particle expansion of ~40% upon full lithiation. The composite electrodes of carbon-nanotube@silicon@carbon-graphite with a practical loading (3 mAh cm −2 ) deliver ~750 mAh g −1 specific capacity, <20% initial swelling at 100% state-of-charge, and ~92% capacity retention over 500 cycles. Calendered electrodes achieve ~980 mAh cm −3 volumetric capacity density and <50% end-of-life swell after 120 cycles. Full cells with LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathodes demonstrate >92% capacity retention over 500 cycles. This work is a leap in silicon anode development and provides insights into the design of electrode materials for other batteries. The authors here construct hierarchical porous CNT@Si@C microspheres as anodes for Li-ion batteries, enabling both high electrochemical performance and excellent mechanical strength. The work highlights the importance of mechanical properties in developing battery materials for practical applications.