Hybridizing δ-type NaxV2O5·nH2O with graphene towards high-performance aqueous zinc-ion batteries. (20th October 2019)

• Record Type: Journal Article
• Authors: Zhou, Weijun; Chen, Jizhang; He, Cuilan; Chen, Minfeng; Xu, Xinwu; Tian, Qinghua; Xu, Junling; Wong, Ching-Ping
• Is Part Of: Electrochimica acta. Volume 321(2019)
• Publication Date: 2019-10-20
• Subjects: Sodium vanadate -- Layered structure -- Graphene -- Aqueous batteries -- Zinc ion storage; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.134689
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Thanks to low cost and high safety, aqueous zinc-ion batteries (AZIBs) are attractive candidates for large-scale energy storage applications, while suitable cathode materials are needed urgently. In this work, δ-Nax V2 O5 ·nH2 O with a large interlayer spacing of 10.6 Å is reported as the cathode material for aqueous zinc-ion batteries for the first time. It is found that δ-Nax V2 O5 ·nH2 O performs better than Na2 V6 O16 ·nH2 O under the same condition, and its electrochemical performances can be significantly improved after hybridizing it with reduced graphene oxide. The obtained nanocomposite can deliver high reversible capacity of 433.5 mAh g −1 at 0.1 A g −1, superior rate capability of 244.1 mAh g −1 at 5 A g −1, and good cyclability of 70.5% over 1000 cycles. Such great performances origin from the synergetic effect of δ-Nax V2 O5 ·nH2 O and graphene, which enables rapid Zn 2+ diffusion and large capacitive contribution. Besides, the ex-situ measurement results demonstrate good structural stability and reversible Zn 2+ ion storage behavior of reduced graphene oxide/δ-Nax V2 O5 ·nH2 O nanocomposite. This work extends the knowledge into the material technology of AZIBs. Graphical abstract: Image 1 Highlights: δ-Nax V2 O5 ·nH2 O performs better than Na2 V6 O16 ·nH2 O under the same test environment. The performances of δ-Nax V2 O5 ·nH2 O are greatly improved after modification with rGO. The composite shows low charge transfer impedance and high ion diffusion coefficient. The pseudocapacitive intercalation accounts for more than half of the total capacity. Zinc ion is intercalated into the nanocomposite via a solid solution process.