Prototype System of Rocking-Chair Zn-Ion Battery Adopting Zinc Chevrel Phase Anode and Rhombohedral Zinc Hexacyanoferrate Cathode

Abstract

Zinc-ion batteries (ZIBs) have received attention as one type of multivalent-ion batteries due to their potential applications in large-scale energy storage systems. Here we report a prototype of rocking-chair ZIB system employing Zn 2 Mo 6 S 8 (zinc Chevrel phase) as an anode operating at 0.35 V, and K 0.02 (H 2 O) 0.22 Zn 2.94 [Fe(CN) 6 ] 2 (rhombohedral zinc Prussian-blue analogue) as a cathode operating at 1.75 V (vs. Zn/Zn 2+ ) in ZnSO 4 aqueous electrolyte. This type of cell has a benefit due to its intrinsic zinc-dendrite-free nature. The cell is designed to be positive-limited with a capacity of 62.3 mAh g −1 . The full-cell shows a reversible cycle with an average discharge cell voltage of ~1.40 V, demonstrating a successful rocking-chair zinc-ion battery system. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.