MOF-derived hollow Si with dual Al layers as a high-performance lithium-ion battery film anode

Si-based anodes are limited in their widespread application mainly because of their significant volume expansion during cycling. In this study, the hollow Si thin film anode (H-Si-0.1) was prepared using ZIF-8 as a sacrificial template, followed by etching with 0.1 M hydrochloric acid (HCl). The hollow Si was coated with dual Al layers on its inner and outer surfaces, forming the Al/H-Si-0.1/Al composite thin film anode. The hollow structure provides buffering space to accommodate volume change and facilitates the formation of a gyrification-like structure on the film anode during cycling, significantly enhancing cycling stability. Moreover, the hollow structure creates efficient diffusion pathways for lithium ions, improving ion transport. The dual Al layers provide mechanical support for the structural stability of the anode and suppress side reactions. The Al/H-Si-0.1/Al thin film anode provides a high reversible capacity of 2098 mA h g −1 at 0.5 A g −1 . It exhibits a specific capacity of 1512 mA h g −1 at 5 A g −1 after 300 cycles, achieving a capacity retention of 94.56 %.