Ultrathin δ-MnO2 nanosheets as cathode for aqueous rechargeable zinc ion battery. (1st May 2019)

• Record Type: Journal Article
• Authors: Guo, Cong; Liu, Huimin; Li, Jingfa; Hou, Zhiguo; Liang, Jianwen; Zhou, Jie; Zhu, Yongchun; Qian, Yitai
• Is Part Of: Electrochimica acta. Volume 304(2019)
• Page Start: 370
• Page End: 377
• Publication Date: 2019-05-01
• Subjects: Aqueous zinc ion battery -- δ-MnO2 -- Ultrathin nanosheets -- Self-sacrificing template -- Co-insertion; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.03.008
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Ultrathin δ-MnO2 nanosheets were synthesized via in-situ reduction of KMnO4 on graphene oxide using graphene oxide as both reductant and self-sacrificing template. The layered δ-MnO2 nanosheets with a thickness of about 2–4 nm inherit the two-dimensional lamellar morphology of graphene oxide. When used as cathode for aqueous zinc ion batteries, the prepared δ-MnO2 nanosheets exhibit a reversible capacity of 133 mAh/g at a current density of 100 mA/g over 100 cycles and a capacity of 86 mAh/g at 500 mA/g due to the layered structure and ultrathin morphology, which is much better than δ-MnO2 microspheres. The electrochemical and structural investigation indicates a possible mechanism of two-step co-insertion of H + and Zn 2+ into the interlayer of δ-MnO2 during discharge process. It's believed that the unique ultrathin morphology of δ-MnO2 can well facilitate ion diffusion and structure stability during cycling, making ultrathin δ-MnO2 nanosheets a promising cathode in aqueous zinc ion batteries. Graphical abstract: Image 1 Highlights: Ultrathin δ-MnO2 nanosheets are synthesized by GO as self-sacrificing template. Ultrathin δ-MnO2 nanosheets are used as the cathode in aqueous zinc ion batteries. δ-MnO2 ultrathin nanosheets exhibit better performances than δ-MnO2 microspheres. Nice properties are due to layered structure and ultrathin morphology of δ-MnO2 . H + and Zn 2+ insert/extract successively during the electrochemical process.