Electrochemical Zintl Cluster Bi22− induced chemically bonded bismuth / graphene oxide composite for sodium-ion batteries

• Bismuth, a promising attribute for sodium-ion batteries, which have been attracting significant attention owing to their advantages of high volumetric capacity and suitable operating potential. However, most traditional Bi-based materials are suffered from pulverization and fracture of the electrodes caused by dramatic volume variation, consequently diminishing the cycle stability. Herein, in this work, bismuth embedded within graphene oxide matrices have been obtained by utilizing a novel and efficient electrochemical method. Through the strong reducing properties of Zintl clusters Bi22−, GO is partially reduced to generate reduced graphene oxide with better electrical conductivity. Simultaneously, Bi is strongly loaded on the GO through Bi-O-C bonding, which can form Bi2O22+ with excellent ionic conductivity. Moreover, the volume expansion of Bi during sodiation can be effectively buffered in the GO matrices. As a result, this Bi/GO composite exhibits excellent electrochemical performances in sodium-ion batteries (SIBs), including a high specific capacity of 258 mAh g−1 at 10 A g−1 and an excellent cycle stability with high retained capacity of 315 mAh g−1 after 500 cycles at 2 A g−1. This work paves the way to prepare designated promising electrode materials for high-performance SIBs, and thoroughly understands mechanism of electrochemical methods for preparing materials.

Subject headings

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

Sodium-ion batteries

Bi/GO composite

Electrochemical method

Anode materials

Zintl clusters

Publication and Content Type

ref (subject category)

art (subject category)