The Synthesis of Manganese Hydroxide Nanowire Arrays for a High-Performance Zinc-Ion Battery.

The morphology, microstructure as well as the orientation of cathodic materials are the key issues when preparing high-performance aqueous zinc-ion batteries (ZIBs). In this paper, binder-free electrode Mn(OH) 2 nanowire arrays were facilely synthesized via electrodeposition. The nanowires were aligned vertically on a carbon cloth. The as-prepared Mn(OH) 2 nanowire arrays were used as cathode to fabricate rechargeable ZIBs. The vertically aligned configuration is beneficial to electron transport and the free space between the nanowires can provide more ion-diffusion pathways. As a result, Mn(OH) 2 nanowire arrays yield a high specific capacitance of 146.3 Ma h g -1 at a current density of 0.5 A g -1 . They also demonstrates ultra-high diffusion coefficients of 4.5 × 10 -8 ~1.0 × 10 -9 cm 2 s -1 during charging and 1.0 × 10 -9 ~2.7 × 10 -11 cm -2 s -1 during discharging processes, which are one or two orders of magnitude higher than what is reported in the studies. Furthermore, the rechargeable Zn//Mn(OH) 2 battery presents a good capacity retention of 61.1% of the initial value after 400 cycles. This study opens a new avenue to boost the electrochemical kinetics for high-performance aqueous ZIBs.