Microstructure modulation improving stability performance of Bi anode for lithium-ion batteries

Abstract

Metal Bi is a classic metal-type anode material characterized by its high volume-specific capacity (3785 mAh cm-3) and theoretical specific capacity (386 mAh g-1). However, during the charge and discharge processes of the battery, Bi undergoes significant volume expansion and contraction, which leads to a notable decline in battery performance. In this work, to suppress the volume expansion of bismuth and enhance battery performance and stability, Bi-metal-organic-framework (Bi-MOF) is utilized as a precursor and combined with an organic polymerization coating process, followed by calcination, to obtain a double-carbon-coated lamellar structure (Bi/C@CPpy). The coated carbon layers inhibit the agglomeration of Bi particles and mitigate volume changes during charge-discharge cycles. After 100 cycles at 0.1 A g-1, Bi/C@CPpy maintains a specific capacity of 526.4 mAh g-1. Even after 900 extended cycles, it retains a specific capacity of 255.6 mAh g-1 at 0.5 A g-1. In-situ XRD is employed to analyze the Li⁺ storage mechanism. Furthermore, a full cell with Li1.2Ni0.13Co0.13Mn0.64O2 as the cathode and Bi/C@CPpy-based anode achieves a capacity of 104.3 mAh g-1 after 100 cycles at a current density of 0.05 A g-1. This approach provides valuable insights into the precise structural design and preparation of high-performance rechargeable battery alloy negative electrode materials.