Bi Nanoparticles Anchored in N-Doped Porous Carbon as Anode of High Energy Density Lithium Ion Battery

Abstract

A novel bismuth-carbon composite, in which bismuth nanoparticles were anchored in a nitrogen-doped carbon matrix (Bi@NC), is proposed as anode for high volumetric energy density lithium ion batteries (LIBs). Bi@NC composite was synthesized via carbonization of Zn-containing zeolitic imidazolate (ZIF-8) and replacement of Zn with Bi, resulting in the N-doped carbon that was hierarchically porous and anchored with Bi nanoparticles. The matrix provides a highly electronic conductive network that facilitates the lithiation/delithiation of Bi. Additionally, it restrains aggregation of Bi nanoparticles and serves as a buffer layer to alleviate the mechanical strain of Bi nanoparticles upon Li insertion/extraction. With these contributions, Bi@NC exhibits excellent cycling stability and rate capacity compared to bare Bi nanoparticles or their simple composites with carbon. This study provides a new approach for fabricating high volumetric energy density LIBs.

Keywords: Anode; Bi nanoparticles; High energy density; Lithium-ion battery; Porous N-doped carbon.

Fig. 1

Lithium storage performances of various metals in comparison to graphite

Fig. 2

Schematic illustration of the formation process of Bi@NC

Fig. 3

a XRD pattern, b FTIR spectrum, and c, d SEM images of ZIF-8 precursors

Fig. 4

a XRD pattern, b SEM, c TEM, and d HRTEM and SAED images of Zn@NC

Fig. 5

a XRD pattern, b SEM, c TEM, HRTEM, and d SAED images of Bi@NC

Fig. 6

a Cyclic voltammograms and b charge–discharge curves of Bi@NC; comparisons of c cyclic stability, d coulombic efficiency, and e rate capabilities of Bi@NC, Bi@C, and bare Bi

Fig. 7

CV characteristics of a Bi@NC, b Bi@C and c bare Biat scanning rates ranging from 0.2 to 1.0 mV s⁻¹. d Linear relations of anodic peak currents (i_p) versus the square roots of scanning rate (υ)

Fig. 8

XRD patterns revealing a structural and chemical evolution and b corresponding mechanism of the Bi@NC electrode