Conductive 2D metal-organic framework for high-performance cathodes in aqueous rechargeable zinc batteries.

Nam, Kwan Woo; Park, Sarah S; Dos Reis, Roberto; Dravid, Vinayak P; Kim, Heejin; Mirkin, Chad A; Stoddart, J Fraser · Nat Commun · 2019

basic_science · Level V

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Abstract

Currently, there is considerable interest in developing advanced rechargeable batteries that boast efficient distribution of electricity and economic feasibility for use in large-scale energy storage systems. Rechargeable aqueous zinc batteries are promising alternatives to lithium-ion batteries in terms of rate performance, cost, and safety. In this investigation, we employ Cu<sub>3</sub>(HHTP)<sub>2</sub>, a two-dimensional (2D) conductive metal-organic framework (MOF) with large one-dimensional channels, as a zinc battery cathode. Owing to its unique structure, hydrated Zn<sup>2+</sup> ions which are inserted directly into the host structure, Cu<sub>3</sub>(HHTP)<sub>2</sub>, allow high diffusion rate and low interfacial resistance which enable the Cu<sub>3</sub>(HHTP)<sub>2</sub> cathode to follow the intercalation pseudocapacitance mechanism. Cu<sub>3</sub>(HHTP)<sub>2</sub> exhibits a high reversible capacity of 228 mAh g<sup>-1</sup> at 50 mA g<sup>-1</sup>. At a high current density of 4000 mA g<sup>-1</sup> (~18 C), 75.0% of the initial capacity is maintained after 500 cycles. These results provide key insights into high-performance, 2D conductive MOF designs for battery electrodes.