Lattice-confined localized alloying of Bi0.67TaS2 anode enabling ultrafast and stable sodium storage up to 150 C

Bismuth is considered to be a promising anode for sodium-ion batteries due to its low voltage plateau and high volumetric capacity. However, the large volume variation during alloying/dealloying leads to electrode pulverization and performance degradation, especially under high current densities. Herein we propose a lattice-confined localized alloying reaction mechanism to solve the above issues. By chemically embedding Bi atoms in a rigid layered host framework, the alloying reaction of Bi is spatially and kinetically confined within the interlayer, allowing for complete recovery of the Bi0.67TaS2 crystal structure after desodiation. The as-prepared Bi0.67TaS2 anode exhibits superior rate performance, achieving capacities of 256 mAh g at 1 C and 186 mAh g at 150 C, along with remarkable long-term cycling stability for maintaining 153 mAh g after 20000 cycles at 150 C. This work demonstrates that the localized alloying mechanism enabled by lattice confinement significantly contributes to both rate and cycling performance, which is expected to provide insights into electrode design for future fast-charging batteries.