Multi-walled Bi2O3/Bi@C particles as a high-performance anode material for lithium-ion batteries

Abstract

Bismuth (Bi) based materials possess an excellent volumetric capacity (3800 mAh cm⁻³), but their application is hindered by significant volume expansion and slow reaction kinetics during cycling. This study proposes a multi-walled strategy to synthesize multi-walled Bi₂O₃, effectively mitigating volume expansion during cycling. Building on this approach, we develop a multi-walled Bi₂O₃/Bi@C composite electrode, incorporating pseudocapacitance to further enhance its electrochemical performance. During subsequent charge-discharge cycles, the multi-walled Bi₂O₃/Bi@C composite electrode demonstrates satisfactory performance. At a current density of 0.5 A/g, it maintains a stable capacity of 280 mAh g⁻¹ after 500 cycles, with a high energy density of 183 Wh/kg. Even at a current density of 1 A/g, the capacity remains stable at 180 mAh g⁻¹ after 500 cycles. Through extensive cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT), and distribution of relaxation times (DRT) tests, we reveal the reaction kinetics of the composite. The results show a pseudocapacitive contribution of 75.62 % at a scan rate of 1.0 mV/s and a calculated Li⁺ diffusion coefficient (D_Li⁺) ranging from 10⁻¹² to 10⁻¹⁴ cm²/s. Furthermore, we identify six electrode reaction processes associated with solution resistance (Re), SEI film formation (Rs), charge transfer resistance (Rct), and ion diffusion resistance (Wo). This study provides new insights into developing high-performance and long-lasting Bi-based anodes for lithium-ion batteries.