Affiliation:
1. Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University Xi'an Shaanxi 710072 P. R. China
2. College of Chemistry and Chemical Engineering Xi‘an University of Science and Technology Xi'an Shaanxi 710054 P. R. China
Abstract
AbstractWith the growing demand for new energy storage devices, rechargeable aqueous zinc ion batteries (ZIBs) have attracted widespread attention due to their low cost and high safety. Among the cathode materials for ZIBs, polyanionic–based cathode materials with high voltage, high stability, and low cost have great potential. In this paper, tetragonal Na2VOP2O7 was prepared using a simple sol–gel method. The discharge platform voltage amounted to 1.8 V and had good rate and cycle performance due to the inductive effect of pyrophosphate. Then, a protective layer of Zn–hydroxyapatite (ZnHAP) modification was applied to the cathode surface, which can inhibit the hydrolysis of vanadium ions. The capacity was enhanced by 19 % after modification and the capacity retention after 100 cycles was also higher. Interestingly, the Na2VOP2O7 cathode also possesses a self–charging effect, recovering to 48 % of its initial capacity with an open–circuit voltage (OCV) of 1.1 V within a certain period, and light exposure can reduce the self–charging time by 83 %. These beneficial results indicate that the pyrophosphate bifunctional cathode with inductive effect has a great potential to construct high–voltage and multifunctional zinc ion battery.
Funder
National Natural Science Foundation of China