Filling the Charge–Discharge Voltage Gap in Flexible Hybrid Zinc‐Based Batteries by Utilizing a Pseudocapacitive Material
Ling Wang, Xiao‐Tong Wang, Jia‐Huan Zhong, Kang Xiao, Ting Ouyang, Zhao‐Qing Liu
Abstract
Abstract The high charge–discharge voltage gap is one of the main bottlenecks of zinc–air batteries (ZABs) because of the kinetically sluggish oxygen reduction/evolution reactions (ORR/OER) on the oxygen electrode side. Thus, an efficient bifunctional catalyst for ORR and OER is highly desired. Herein, honeycomb‐like MnCo 2 O 4.5 spheres were used as an efficient bifunctional electrocatalyst. It was demonstrated that both ORR and OER catalytic activity are promoted by Mn IV ‐induced oxygen vacancy defects and multiple active sites. Importantly, the multivalent ions present in the material and its defect structure endow stable pseudocapacitance within the inactive region of ORR and OER; as a result, a low charge–discharge voltage gap (0.43 V at 10 mA cm −2 ) was achieved when it was employed in a flexible hybrid Zn‐based battery. This mechanism provides unprecedented and valuable insights for the development of next‐generation metal–air batteries.