Electrochemical performance of KTiOAsO4 (KTA) in potassium-ion batteries from density-functional theory

The electrochemical performance of potassium titanyl arsenate (KTiOAsO4, KTA) as the cathode and anode in K-ion batteries is calculated within density-functional theory. Cathodes and anodes are modeled using K-deficient K1-xTiOAsO4 (x = 0.0-1.0) and K-doped KTiOAsO4Kx (x = 0.0-0.5), respectively. For KTA cathodes/anodes a slightly larger/smaller open circuit voltage is found than predicted for potassium titanyl phosphate. The present results suggest that a solely KTA-based K-ion battery can reach an average working voltage of about 3.8 V. The migration barriers of K vacancies and K dopants are found to be smaller than 750 meV. In addition, the present calculations show a very moderate volume expansion and shrinkage upon K intercalation and deintercalation. Our results suggest KTA to be a promising electrode material for K-ion batteries.

Automated summary

The electrochemical performance of potassium titanyl arsenate (KTA) as the cathode and anode in K-ion batteries was calculated using density-functional theory. The results showed that KTA-based K-ion batteries have a higher working voltage and moderate volume change, suggesting that KTA is a promising electrode material.