Electrochemistry of rechargeable aqueous zinc/zinc-sulphate/manganese-oxide batteries and methods for preparation of high-performance cathodes. Issue 29 (6th July 2022)

• Record Type: Journal Article
• Authors: Gong, Wei; Fugetsu, Bunshi; Mao, Wei; Vipin, Adavan Kiliyankil; Sakata, Ichiro; Su, Lei; Zhang, Xueji; Endo, Morinobu
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 29(2022)
• Page Start: 15415
• Page End: 15426
• Publication Date: 2022-07-06
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta03729g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : New insights into the cathode's electrochemistry and a nanomanufacturing strategy to enhance the electrochemical performance of rechargeable aqueous Zn/ZnSO4 /MnO2 batteries are described. Abstract : Rechargeable aqueous Zn/ZnSO4 /MnO2 batteries, due to their high performance and safety, have attracted much attention as promising candidates for grid-scale energy storage. Despite intensive efforts in previous studies, the cathode electrochemistry remains largely unidentified. We observed new insights into the cathode electrochemistry in Zn/ZnSO4 /MnO2 batteries and found that, regardless of the physicochemical states of manganese in the pristine, as-prepared cathode, birnessite is the fated compound. The birnessite consisted of both Mn(iii ) and Mn(iv ) with Zn 2+ as the foreign cation. Birnessite stores energy via chemical redox reactions. Mn(iii ) has the highest priority for discharge. Mn(iv ) discharges stepwise, first to MnO–OH, and then MnO–OH continuously discharges to Mn 2+ . During recharge, birnessite is produced stepwise via Mn 2+ → MnO–OH and MnO–OH → birnessite. Zinc sulphate hydroxide plays essential roles in driving discharge and recharge via its formation with hydroxyl ions (by-products of discharge) and via neutralization of proton ions (by-products of recharge). We inserted birnessite into three-dimensional networks of single-walled carbon nanotubes (3D-SWCNT-networks) via electrochemical deposition and the superior conductive properties of the birnessite/3D-SWCNT-networks have extended the cycling numbers of the rechargeable aqueous Zn/ZnSO4 /MnO2 batteries over 11 000 with a capacity retention > 82.5% at a high discharge/recharge rate of 1.5 A g −1 . The rechargeable aqueous Zn/ZnSO4 /MnO2 batteries with birnessite/3D-SWCNT-networks as cathodes are the promising devices for applications in long-term energy storage.