Cryptomelane-type MnO2/carbon nanotube hybrids as bifunctional electrode material for high capacity potassium-ion full batteries. (December 2018)

• Record Type: Journal Article
• Authors: Chong, Shaokun; Wu, Yifang; Liu, Chaofeng; Chen, Yuanzhen; Guo, Shengwu; Liu, Yongning; Cao, Guozhong
• Is Part Of: Nano energy. Volume 54(2018)
• Page Start: 106
• Page End: 115
• Publication Date: 2018-12
• Subjects: Potassium-ion battery -- Cryptomelane -- Bifunctional electrode -- High capacity -- Full cells; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.09.072
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Potassium-ion batteries (PIBs) have been receiving a great deal of attention owing to abundant and cost-effective potassium resources. However, the key issue is to explore suitable electrode materials for accommodating the large size K-ions reversibly. In this report, K1.06 Mn8 O16 /CNT hybrids are systematically studied for the first time as bifunctional PIBs-electrodes, in which Mn-ions play as the redox center. As the cathode, it exhibits excellent electrochemical kinetics and reversibility, as well as highly structure stability. The cathode displays an unprecedented capacity of 309.4 mA h g −1 at 20 mA g −1 with the energy density of 733.3 Wh kg −1 and outstanding rate performance (187.1 mA h g −1 at 500 mA g −1 ). In addition, the high capacity of 636.6 mA h g −1 at 20 mA g −1, ultra-long cycling lifespan over 500 cycles and remarkable rate capability can also be acquired when the material was tested as the anode. The extraordinary electrochemical properties are ascribed to the well-developed conductive network and robust microstructure stability. Meanwhile, the symmetrical K-ions full cell exhibits high discharge capacity of 241.0 mA h g −1 at 100 mA g −1 . This work reveals the K-ions storage mechanism in cryptomelane bifunctional electrodes in depth and the fundamental understanding help us open up a new direction for PIBs. Graphical abstract: Highlights: K1.06 Mn8 O16 /CNT nanohybrid was employed as bifunctional PIBs-electrodes for the first time. The bifunctional electrodes exhibit excellent electrochemical performances benifited its unique 3D network architecture. The K-ions storage mechanism for cathode is studied in depth. The symmetrical K-ions full cell with high discharge capacity was confirmed based on bifunctional electrodes.