Exploring Pillar[6]quinone as Cathode Material for Aqueous Zinc‐Ion Batteries

In this study, Pillar[6]quinone (P6Q) is first employed as a cathode material for aqueous zinc batteries. The P6Q/Ketjen Black electrode exhibited noteworthy electrochemical stability (75%) accompanied by coulombic efficiency (97%), and also capacity retention of 83% after 10 000 cycles at a current density of 50 C. The electrochemical mechanism of P6Q was investigated using theoretical calculation and ex situ characterization techniques.

Quinone cathodes have wide application prospects in aqueous zinc-ion batteries (AZIBs) due to their high performance, structural diversity, sustainability, high specific capacity, and fast reaction kinetics. Herein, pillar[6]quinone (P6Q), a member of the quinone group, is used as a cathode in AZIBs for the first time. The P6Q structure consisting of six benzoquinone units with a higher cavity than the quinone structures with small molecule structures is found to greatly improve the cycling stability of the cathode. The P6Q electrode exhibits remarkable electrochemical stability and a long-term cycle life (discharge capacity of 118 mAh g⁻¹ and capacity retention of 83% after 10 000 cycles at current density of 50C). In addition, density functional theory calculations and ex situ characterization methods such as ultraviolet–visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy are used to clarify the possible coordination mechanism between P6Q and Zn²⁺/H⁺ ions.

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