Oxygen-vacancy abundant alpha bismuth oxide with enhanced cycle stability for high-energy hybrid supercapacitor electrodes

Bi2O3 is an outstanding electrode material due to its high theoretical specific capacity. Hence, the synthesis of delta-Bi2O3 materials with high oxygen-vacancy contents could improve their electrochemical performances but causes easy conversion to alpha-Bi2O3 with low oxygen-vacancy contents, leading to poor cycling stability and limited practical applications. To overcome these problems, an effective strategy for constructing high oxygen vacancies alpha-Bi2O3 on activated carbon fiber paper (ACFP) is developed in this study. To this end, ACFP/Bi(OH)(3) is first synthesized by the solvothermal method and then converted to ACFP/alpha-Bi2O3 by in situ electrochemical activation. The proposed innovative electrochemical method quickly and easily introduces oxygen vacancies while preserving the three-dimensional structure, thereby promoting the charge transfer and ions diffusion in ACFP/alpha-Bi2O3. Consequently, the specific capacity of ACFP/alpha-Bi2O3 reaches 906C g(-1) at 1 A g(-1), and the capacity retention remains above 70% after 3000 cycles, a value higher than that of delta-Bi2O3 (45%). Furthermore, the hybrid supercapacitor device assembled by ACFP/alpha-Bi2O3 delivers a maximum energy density of 114.9 Wh kg(-1) at 900 W kg(-1) and outstanding cycle stability with 73.56 % retention after 5500 cycles. In sum, the proposed ACFP/alpha-Bi2O3 with high performance and good stability looks promising for use as bismuth-based anode materials in supercapacitors and aqueous batteries. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A high oxygen vacancy alpha-Bi2O3 material was successfully constructed on activated carbon fiber paper, showing improved electrochemical performance, good cycle stability, and high specific capacity. This innovative strategy holds promise for applications in supercapacitors and aqueous batteries.