Electrochemical performance of Bi2O3 supercapacitors improved by surface vacancy defects. Issue 6 (15th March 2021)

• Record Type: Journal Article
• Authors: Yang, Shiju; Qian, Libing; Ping, Yunjie; Zhang, Haoliang; Li, Jingjing; Xiong, Bangyun; Fang, Pengfei; He, Chunqing
• Is Part Of: Ceramics international. Volume 47:Issue 6(2021)
• Page Start: 8290
• Page End: 8299
• Publication Date: 2021-03-15
• Subjects: Bi2O3 -- Pseudo-capacitance -- Vacancy defects -- Electrochemical performance; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.11.190
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Vacancy defects have important impacts on the physical-chemical properties of metal oxides. In the present work, two types of Bi2 O3 powders with different morphologies were synthesized for supercapacitor electrodes by calcination (denoted as c-Bi2 O3 ) and two-step hydrothermal methods (donated as h-Bi2 O3 ). Vacancy clusters of V B i ‴ V O · · V B i ‴ with different concentrations were observed in these two samples by positron annihilation lifetime spectroscopy. The results of electrochemistry revealed that the charge storage behavior of h-Bi2 O3 with more V B i ‴ V O · · V B i ‴ defects obeyed both semi-infinite diffusion-controlled battery-type mechanism and surface-controlled pseudo-capacitance mechanism, while that of the calcined c-Bi2 O3 electrode with a lower concentration of V B i ‴ V O · · V B i ‴ defects followed only the semi-infinite diffusion-controlled battery-type mechanism. The pseudo-capacitance of h-Bi2 O3 could be attributed to the insertion/extraction process of more K + ions in the V B i ‴ V O · · V B i ‴ surface defects. Due to the partial pseudo-capacitance and improved conductivity caused by more V B i ‴ V O · · V B i ‴ defects, the h-Bi2 O3 electrode had a larger capacitance (1043 F g -1 at 1 A g -1 ), a higher rate performance (560 F g -1 at 60 A g -1 ), and better cycle stability (93% retention at 50 A g -1 after 2000 cycles). Furthermore, because of the high-concentration of V B i ‴ V O · · V B i ‴ defects, the Ni/Co-MOF//h-Bi2 O3 asymmetric supercapacitor delivered a relatively higher specific energy density of 47 Wh kg -1 at 1125 W kg -1 . Taken together, these results indicate that surface vacancy clusters play an important role in boosting the electrochemical performance of metal oxide electrodes.