Joint Charge Storage for High-Rate Aqueous Zinc-Manganese Dioxide Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 31157468.
- Also identified by DOI 10.1002/adma.201900567.
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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<sub>2</sub> cathodes. In the literature various intercalation and conversion reaction mechanisms in MnO<sub>2</sub> 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<sub>2</sub> cathode is reported. An electrolyte-dependent reaction mechanism in δ-MnO<sub>2</sub> is identified. Nondiffusion controlled Zn<sup>2+</sup> intercalation in bulky δ-MnO<sub>2</sub> and control of H<sup>+</sup> conversion reaction pathways over a wide C-rate charge-discharge range facilitate high rate performance of the δ-MnO<sub>2</sub> cathode without sacrificing the energy density in optimal electrolytes. The Zn-δ-MnO<sub>2</sub> system delivers a discharge capacity of 136.9 mAh g<sup>-1</sup> 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.