He Yang, Zhou Feng, Zhang Yingxi, Lv Tuan, Chu Paul K, Huo Kaifu
Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan, 430074, P. R. China.
Department of Physics, Department of Materials Science and Engineering, and Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, 999077, P. R. China.
Small. 2024 Nov;20(45):e2404556. doi: 10.1002/smll.202404556. Epub 2024 Jul 19.
Silicon (Si) is a promising anode material for high-energy-density lithium-ion batteries, but the significant volume change of Si particles during alloying/dealloying with lithium (Li) undermines the mechanical integrity of Si anode, causing electrode fracture, delamination and rapid capacity decay. Herein, a robust triple crosslinked network (TCN) binder with high ionic conductivity and hierarchical stress dissipation is reported for Si anodes, which is prepared by in situ chemical crosslinking polyacrylic acid (PAA) and melamine (MA). The triple interactions of hydrogen bonds, electrostatic interactions, and covalent amide bonds enhance the adhesion of binder to Si and synergistically promote stress dissipation within Si anodes, thus strengthening the dynamic structural stability of Si anodes during cycling. Moreover, the rapid coupling/decoupling of Li with the TCN binder enables an impressive Li transference number of 0.63 and high ionic conductivity of 1.2 × 10 S cm. Consequently, the Si-TCN anode delivers specific capacity of 2268 mAh g with a high mass loading of 2 mg cm, high-rate performance of 1673 mAh g at 5 A g, and stable cycling for 250 cycles at 1 A g, thus showing great prospects for high-energy-density Si-based batteries.
硅（Si）是一种很有前景的用于高能量密度锂离子电池的负极材料，但是硅颗粒在与锂（Li）合金化/脱合金化过程中显著的体积变化破坏了硅负极的机械完整性，导致电极断裂、分层以及快速的容量衰减。在此，报道了一种用于硅负极的具有高离子导电性和分级应力耗散的坚固的三交联网络（TCN）粘结剂，它是通过原位化学交联聚丙烯酸（PAA）和三聚氰胺（MA）制备的。氢键、静电相互作用和共价酰胺键的三重相互作用增强了粘结剂与硅的粘附力，并协同促进硅负极内的应力耗散，从而在循环过程中增强了硅负极的动态结构稳定性。此外，锂与TCN粘结剂的快速耦合/去耦合实现了令人印象深刻的0.63的锂迁移数和1.2×10 S cm的高离子导电性。因此，硅-TCN负极在2 mg cm的高质量负载下提供2268 mAh g的比容量，在5 A g下具有1673 mAh g的高倍率性能，并且在1 A g下稳定循环250次，从而显示出在高能量密度硅基电池方面的巨大前景。
