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Joint Charge Storage for High-Rate Aqueous Zinc-Manganese Dioxide Batteries.

Authors :: Jin Y
Zou L
Liu L
Engelhard MH
Patel RL
Nie Z
Han KS
Shao Y
Wang C
Zhu J
Pan H
Liu J
Source :: Advanced materials (Deerfield Beach, Fla.) [Adv Mater] 2019 Jul; Vol. 31 (29), pp. e1900567. Date of Electronic Publication: 2019 Jun 03.
Publication Year :: 2019
Abstract: Aqueous rechargeable zinc-manganese dioxide batteries show great promise for large-scale energy storage due to their use of environmentally friendly, abundant, and rechargeable Zn metal anodes and MnO <subscript>2</subscript> cathodes. In the literature various intercalation and conversion reaction mechanisms in MnO <subscript>2</subscript> have been reported, but it is not clear how these mechanisms can be simultaneously manipulated to improve the charge storage and transport properties. A systematical study to understand the charge storage mechanisms in a layered δ-MnO <subscript>2</subscript> cathode is reported. An electrolyte-dependent reaction mechanism in δ-MnO <subscript>2</subscript> is identified. Nondiffusion controlled Zn <superscript>2+</superscript> intercalation in bulky δ-MnO <subscript>2</subscript> and control of H <superscript>+</superscript> conversion reaction pathways over a wide C-rate charge-discharge range facilitate high rate performance of the δ-MnO <subscript>2</subscript> cathode without sacrificing the energy density in optimal electrolytes. The Zn-δ-MnO <subscript>2</subscript> system delivers a discharge capacity of 136.9 mAh g <superscript>-1</superscript> at 20 C and capacity retention of 93% over 4000 cycles with this joint charge storage mechanism. This study opens a new gateway for the design of high-rate electrode materials by manipulating the effective redox reactions in electrode materials for rechargeable batteries.<br /> (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)