Calcium-organic frameworks cathode for high-stable aqueous Zn/organic batteries

Rechargeable aqueous zinc-ion batteries(AZIBs) are attracting tremendous attention because of their intrinsic merits such as high safety and low cost. Cathode plays a critical role in enhancing the electrochemical performance of AZIBs. However, it is difficult to design a robust and high-efficiency cathode material and further implement the commercialization of AZIBs. Metal-organic frameworks(MOFs) electroactive compounds are attractive to serve as the cathode of AZIBs due to their unique porosity and crystal structures, resource renewability and structural diversity. In this work, a calcium-pure terephthalates acid framework(Ca-PTA·3H2O) was synthesized by facile hydrolysis and cationic exchange method,then explored as a novel cathode for AZIBs. The results highlight a high specific capacity of 431 mAh/g(0.51 mAh/cm2) at a current density of 50 mA/g, and excellent cycle performance with capacity retention of ～90% after 2700 cycles at 500 m A/g. The following up characterizations investigate the reversible zinc storage mechanism in detail. This experiment made a specific contribution to the exploration of the new MOF as a competitive cathode for AZIBs.