Hierarchical porous silicon structures with extraordinary mechanical strength as high-performance lithium-ion battery anodes
Haiping Jia, Xiaolin Li, Junhua Song, Xin Zhang, Langli Luo, Yang He, Binsong Li, Yun Cai, Shenyang Hu, Xingcheng Xiao, Chongmin Wang, Kevin M. Rosso, Ran Yi, Rajankumar L. Patel, Ji‐Guang Zhang
Abstract
Abstract 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.