A simple method to enhance the lifetime of Ni-rich cathode by using low-temperature dehydratable molecular sieve as water scavenger

Abstract

Ni-rich cathode materials have received much attention because of their high specific capacity, low cost and environmentally friendly characteristic. However, the nickel-rich cathode is extremely sensitive to moisture, which results in poor structure stability and electrochemical performance. Herein, we demonstrate an efficient and simple route to prolong the lifetime of nickel-rich cathode by introducing a low-temperature dehydratable molecular sieve as water scavenger. The residual water content in electrolyte measurement and nuclear magnetic resonance test manifest that molecular sieve can effectively fix the trace H2O and reduce the decomposition rate of electrolyte from 16.6% to 4.0%, respectively. Transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy confirm that the molecular sieve inhibits the fragmentation of the electrode and the side reactions on the surface of the cathode. This approach improves structural integrity and stabilizes surface structure of the cathode, which increases the capacity retention without sacrificing rate performance. This effective strategy can be extended to other cathode materials which are sensitive to moisture to realize good cycling stability.