Bi nanoparticles with different oxidation states embedded in porous carbon nanosheets as high-performance anode for lithium-ion battery

Bi-based material is a new candidate anode for LIBs. Herein, we fabricate Bi nanoparticles (NPs) with dif-ferent oxidation states embedded in mesoporous carbon matrix based on bismuth citrate-engaged etching -pyrolysis strategies. For Bi@MCNSs-50 0, the oxidation state of Bi is Bi3+. Nevertheless, for Bi@MCNSs-700 and Bi@MCNSs-90 0, Bi appears as a metallic phase (Bi0 and Bi3+). Bi@MCNSs-700 shows excellent elec-trochemical properties as anode material for LIBs. Bi@MCNSs-700 has an initial discharge capacity of 1422.65 mAh g-1 at 0.05 A g-1 and it exhibits high capacity of 312 mAh g-1 at 5 A g-1, and exhibits excellent cycling performance (1 A g-1, 393.2 mAh g-1 after 1000 cycles). Such extraordinary performances are at-tributed to (1) ultra-small Bi NPs and suitable oxidation states can provide massive active sites and facilitate Li+ storage. (2) the porous carbon nanosheets can improve the conductivity, and effectively offer sufficient space to adapt to volume changes during cycling, thus improving cycling stability for Li+ storage. This work provides perspective into the design of excellent Bi-based materials for LIBs.& COPY; 2023 Elsevier B.V. All rights reserved.

Automated summary

In this study, Bi nanoparticles with different oxidation states are fabricated and embedded in a mesoporous carbon matrix using bismuth citrate-engaged etching-pyrolysis strategies. Among them, Bi@MCNSs-700 exhibits excellent electrochemical properties as an anode material for LIBs, showing high initial discharge capacity, high capacity at high current densities, and excellent cycling stability. This is attributed to the ultra-small Bi nanoparticles providing massive active sites and the porous carbon nanosheets improving conductivity and accommodating volume changes.