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

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 Zn2Mo6S8 (zinc Chevrel phase) as an anode operating at 0.35 V, and K-0.02(H2O)(0.22)Zn-2.94[Fe(CN)(6)](2) (rhombohedral zinc Prussian-blue analogue) as a cathode operating at 1.75 V (vs. Zn/Zn2+) in ZnSO4 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 similar to 1.40 V, demonstrating a successful rocking-chair zinc-ion battery system.