A novel CoNi(CN)4 nanosheets/CNT interlayer is designed to prevent shuttle effect by adsorption-catalysis process. The iodine species can be adsorbed and catalyzed on the dual-metal centers of the cyanide bridged coordination polymer. The zinc-iodine dual-plating battery with the interlayer shows impressive areal capacity of 3.6 mAh cm−2 with high cycle stability.
Abstract
Iodine is a promising candidate among the cathode materials in zinc-ion battery. However, iodine cathode suffers from serious shuttle effect by spontaneous generated polyiodide species. In this work, we developed a CoNi(CN)4/CNT interlayer to prevent shuttle effect by adsorption-catalysis process. The adsorption of the iodine species on CoNi(CN)4/CNT interlayer is justified by UV-vis spectroscopy and X-ray photoelectron spectroscopy, where the concentration of polyiodides is significantly reduced, and the binding energy of cobalt, nickel, and nitrogen is remarkably reduced by binding with polyiodides. The zinc-iodine dual-plating battery shows significantly higher areal capacity and cycle stability with CoNi(CN)4/CNT. Moreover, battery with impressive areal capacity of 3.6 mAh cm−2 and negligible fading over 100 cycles is also achieved, which outperforms state-of the art literatures on zinc-iodine batteries.