Layered Hexaphenylbenzene (HPB) derivatives with pseudo-2D structure for high-performance Li ion batteries

Herein, we have synthesized a series of hexaphenylbenzene (HPB) derivatives: HPB-H, HPB-COOCH3 and HPB-COOH that differs in functional groups attached to the periphery of the outer benzene rings. Among them, the HPB with carboxyl functional group (HPB-COOH) as LIB anode shows a superior capacity of 997.4 mAh g(-1) and better rate performance than HPB and HPB-COOCH3. Such superior anode properties can be attributed to the fact that HPB-COOH has a layered morphology, a pseudo-2D structure, lower LUMO energy, and higher electron conductivity, compared with that of HPB-COOCH3 and HPB-H, respectively. Moreover, low energy packing with transport channels is beneficial for Li ions diffusion during the lithiation and extraction processes. Furthermore, HPB-COOH shows excellent cycling stability presumably due to its layered molecular packing structures. Our work paves the way for the design synthesis of novel organic molecules with suitable electrochemical redox-active groups and layered hierarchical structure to achieve high capacity, good rate performance, and high cyclic stability for next generation Li ion batteries (LIBs).

Automated summary

By synthesizing HPB derivatives with different functional groups, HPB-COOH was identified as having superior anode properties for lithium-ion batteries, including higher capacity, better rate performance, and excellent cycling stability. This can be attributed to its layered morphology, pseudo-2D structure, low LUMO energy, and high electron conductivity.