Preparation of ultrafine Ag3BiO3 and modification mechanism on EMD cathode for rechargeable alkaline manganese dioxide battery

• Published in: Journal of materials science. Materials in electronics 2023-08, Vol.34 (23), p.1667, Article 1667
• Main Authors: Gu, Chengyang, Zhang, Zhenzhong, Zhao, Fangxia, Zhang, Youwei, Liu, Yana, Sun, Quan
• Format: Article
• Language: English
• Subjects: Bismuth trioxide; Cathodes; Cetyltrimethylammonium bromide; Characterization and Evaluation of Materials; Charging; Chemistry and Materials Science; Discharge; Dispersants; Dispersion; Disproportionation; Doping; Electrochemical analysis; Electrodes; Manganese dioxide; Materials Science; Optical and Electronic Materials; Phase composition; Rechargeable batteries; Silver nitrate; Ultrafines
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-023-11080-8

To improve the rechargeability and conductivity of electrolytic manganese dioxide (EMD) electrodes in rechargeable alkaline manganese batteries. In this work, ultrafine Ag 3 BiO 3 powders were prepared by a novel hydrothermal in situ dispersion method and doped into EMD electrodes by physical grinding. The effects of hydrothermal time, hydrothermal temperature and cetyltriethylammnonium bromide (CTAB) in-situ dispersant on the phase composition and micromorphology of the prepared powders were investigated, and the synthesis process of ultrafine Ag 3 BiO 3 was recommended. Then, the effect of Ag 3 BiO 3 doping amounts on the electrochemical performance of EMD electrodes was further investigated, and the modification mechanism was deeply discussed. The results showed that well-dispersed spherical Ag 3 BiO 3 of about 100 nm could be synthesized at a molar ratio of AgNO 3 :Bi(NO 3 ) 3 of 2:1, with 3 wt% CTAB as in situ dispersant, and a hydrothermal time of 12 h and a hydrothermal temperature of 120 °C. The discharge specific capacities of the EMD electrode doped with 10 wt% Ag 3 BiO 3 were reached 519.9 mAh/g and 98.3 mAh/g after initial and 50 cycles, respectively, which were 323.5%, 72.15% and 108.8%, 18.3% higher than those of the pure EMD electrode and the EMD electrode doped with 10 wt% Bi 2 O 3 , respectively. The doping of Ag 3 BiO 3 could increase the discharge voltage of the EMD electrode and improve its redox process. Besides, the Bi 3+ ions could form complexes with Mn 2+ and Mn 3+ , inhibit the disproportionation reaction, reduce the production of electrochemically inert products Mn 3 O 4 , and also stimulate the second electron discharge of the EMD electrode, which played an important role in lattice stabilisation. Furthermore, the reduction of Ag + to Ag during charging and discharging could increase the conductivity of the EMD electrode and enhance the modification effect of Bi 3+ . Therefore, the doping of Ag 3 BiO 3 in the EMD electrode could significantly increase the discharge specific capacity and rechargeability. This is an important contribution to the modification mechanism of Ag 3 BiO 3 doped EMD cathode for rechargeable alkaline manganese batteries.