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
Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA.
Nat Commun. 2020 Mar 19;11(1):1474. 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) deliver ~750 mAh g specific capacity, <20% initial swelling at 100% state-of-charge, and ~92% capacity retention over 500 cycles. Calendered electrodes achieve ~980 mAh cm volumetric capacity density and <50% end-of-life swell after 120 cycles. Full cells with LiNiMnCoO 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.
多孔结构硅被认为是克服硅基负极粉化问题的一种很有前景的材料。然而，这些多孔颗粒较差的机械强度限制了它们在实际应用中的体积能量密度。在此，我们设计并合成了具有高孔隙率和非凡机械强度（>200兆帕）的分级碳纳米管@硅@碳微球，并且在完全锂化时表观颗粒膨胀率低至约40%。具有实际负载量（3毫安·厘米）的碳纳米管@硅@碳-石墨复合电极的比容量约为750毫安·克，在100%充电状态下初始膨胀率<20%，在500次循环后容量保持率约为92%。压延电极在120次循环后实现了约980毫安·厘米的体积容量密度和<50%的寿命末期膨胀率。采用LiNiMnCoO正极的全电池在500次循环后容量保持率>92%。这项工作是硅负极发展的一次飞跃，并为其他电池的电极材料设计提供了思路。
