Room-temperature synthesis of VO(OH)2 as a high capacity cathode material for aqueous zinc ion batteries.

The development of satisfactory cathodes plays a key role in the widespread utilization of aqueous zinc ion batteries. Cathode materials with high specific capacity and long cycling life are still urgently needed for aqueous zinc ion batteries. Herein, a new cathode material VO(OH) 2 is synthesized by a facile room-temperature precipitation approach, and its electrochemical characteristics and structural evolution process are investigated. Benefiting from its intrinsic electrochemical activity, the VO(OH) 2 cathode exhibits a remarkable specific capacity of 488 mAh g−1 at 0.1 A g−1, retains a high capacity of 219.1 mAh g−1 at the increased current density of 10 A g−1, and provides a maximum energy density of 439.2 Wh kg−1. In addition, when subjected to a 12,000 cycles charge/discharge test at 10 A g−1, the cathode retains a capacity of 185.8 mAh g−1, highlighting durable cycling performance. The structural evolution analysis reveals that of VO(OH) 2 cathode may be in-situ transformed to an amorphous vanadium oxide V 2 O 5-x in the first charging process, which could reversibly intercalate/deintercalate zinc ions. This research supplies a promising cathode material for aqueous zinc ion batteries and enhances understanding of vanadium oxyhydroxide in metal ion storage. [Display omitted] • VO(OH) 2 was applied as cathode materials in AZIBs for the first time. • It was synthesized by a simple precipitation approach. • It exhibits 488 mAh/g at 0.1 A/g and retained 185.8 after cycling at 10 A/g for 12,000 times. • Its kinetics and structural evolution have been revealed. [ABSTRACT FROM AUTHOR]