Growth confinement and ion transportation acceleration via an in-situ formed Bi4Se3 layer for potassium ion battery anodes

Release time:2024-01-19 Hits:

Key Words:NANOPARTICLES; NANOSHEETS; GRAPHITE

Abstract:Bismuth has gained increasing attention as anodes for advanced potassium-ion batteries because of its high theoretical capacity and suitable voltage plateaus. Although nanosized Bi structures display better properties, their syntheses still remain a great challenge because the low melting point of Bi makes it easily to aggregate into large ingots. Herein, the thin Bi4Se3 coating layer combined with N-doped carbon was introduced onto the Bi nanospheres to chemically confine their overgrowth via an in-situ selenization process. Theoretical calculation and experimental results indicated that the Bi4Se3 coating layer not only exhibits better affinity towards Bi-atoms compared with that of carbon sheet, but also can boost the K-ion diffusion kinetics. In addition, the Bi4Se3 coating layer was unraveled to undergo a reversible conversion/alloying mechanism with unique final dis-charged products of K3BiSe3 and K3Bi, which was responsible for the improved discharge capacity and better cycle properties (A higher capacity of 300 mAh/g maintained after 50 cycles, while it was only 210 mAh/g for the Bi@C electrode). Our work presents an effective and general approach to circumvent the overgrowth issues of bismuth anodes and other metal anodes with low melting points for advanced battery applications.

Volume:621

Issue:

Translation or Not:no