Bismuth Nano-Rods Wrapped with Graphene and N-Doped C as Anode Materials for Potassium- and Sodium-Ion Batteries

Abstract

Alloying-type anode materials have considerably promoted the development of potassium-ion batteries (PIBs) and sodium-ion batteries (SIBs), enabling them to achieve high-energy-density. However, large volume expansion and sluggish dynamic behavior have become key issues affecting electrochemical performance. Herein, bismuth (Bi) nano-rods are anchored on reduced graphene (rGO) and encapsulated via N-doped C (NC) to construct Bi@rGO@NC architecture as anode materials for SIBs and PIBs. The hierarchical confinement effect of three-dimensional conductive networks can not only improve electrode stability upon cycling via suppressing the large volume variation, but also eliminate the band gap of Bi and accelerate ion diffusion, thereby exhibiting favorable electrochemical reaction kinetics. Thus, Bi@rGO@NC contributes an ultra-long lifetime, over 1000 cycles, and an outstanding rate property to SIBs and PIBs. This work can pave the way for the construction of high-performance alloying-type anode materials for SIBs and PIBs.