Reconfiguration of metal-organic frameworks to form ultrafine Bi dots as an excellent high-current performance of lithium-ion battery anode

The investigation of Bi-based metal-organic frameworks (Bi-MOFs) as anode materials has garnered significant attention because of their higher lithium storage capacity. Nevertheless, they are prone to structural collapse when undergoing the process of charging and discharging, resulting in irreversible capacity degradation. In this study, we develop novel Bi-MOF and reduced graphene oxide (RGO) composites named Bi-MOF@RGO-x, where “x” represents the amount of RGO incorporated during the synthesis process. As expected, when used as an anode for LIBs , the Bi-MOF@RGO-15 electrode exhibited an excellent capacity of 400 mAh·g −1 and ultra-long cycling stability of more than 3500 cycles at the current density of 10 A·g −1 (the specific capacity is the same as the second cycle). An interesting Bi-MOF@RGO reconfiguration phenomenon could be observed in that amorphous carbon layers and ultra-small bismuth dots could be obtained after repeated charging/discharging. Meanwhile, the amorphous carbon layers could uniformly wrap around the in-situ deposited bismuth dots to act as a buffer against volume fluctuations during bismuth lithiation and delithiation. The in-situ deposited bismuth dots had a shorter Li + transport path, facilitating faster Li + transport to obtain an excellent rate performance. This reconfiguration did not cause the degradation of battery performance, but on the contrary, was an important reason for obtaining high-performance MOF anodes. This study demonstrates that the reconfiguration of Bi-MOF is a favorable anodic conversion process, providing different insights into studying anodes for MOFs.