Cryptomelane K1.33Mn8O16 as a cathode for rechargeable aqueous zinc-ion batteries. Issue 41 (7th August 2019)

• Record Type: Journal Article
• Authors: Sada, Krishnakanth; Senthilkumar, Baskar; Barpanda, Prabeer
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 41(2019)
• Page Start: 23981
• Page End: 23988
• Publication Date: 2019-08-07
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta05836b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Reversible intercalation of Zn ions in tetragonal K1.33 Mn8 O16 delivers 312 mA h g −1 capacity at a galvanostatic cycling rate of 0.1C with an average voltage of 1.5 V. Abstract : Aqueous rechargeable zinc-ion batteries have immense commercial potential in the primary battery market, which is largely occupied by alkaline zinc/manganese oxide batteries. These storage systems are desirable for large-scale applications due to their superior safety, high capacity, fast ionic conductivity and low cost. Pursuing new Mn-based cathodes for Zn-ion batteries, cryptomelane with a specific chemical composition of K1.33 Mn8 O16 was synthesized using a simple sonochemical technique. The formation of phase pure tetragonal K1.33 Mn8 O16 with I 4/ m symmetry was confirmed by X-ray diffraction. When tested as a cathode for Zn-ion batteries, cryptomelane K1.33 Mn8 O16 demonstrated a high reversible capacity of 312 mA h g −1 at a rate of C/10. Robust cycling stability was observed retaining more than 80% of initial capacity after 650 cycles with ∼99% coulombic efficiency. The intercalation chemistry of Zn–MnO2 systems is very rich involving polymorphism and phase transformations during charge/discharge cycles. Synergizing ex situ X-ray diffraction and spectroscopy with the electrochemical titration technique, we have examined the detailed mechanism of (de)intercalation of Zn 2+ into cryptomelane K1.33 Mn8 O16, which is proposed as a potential cathode for Zn-ion batteries.