Na2Ti3O7: an intercalation based anode for sodium-ion battery applications

Abstract

We report here the electrochemical properties of Na₂Ti₃O₇, a potential non-carbon based, low-voltage anode material for room temperature sodium ion battery applications. A solid-state route was used to prepare Na₂Ti₃O₇. Further, XRD, SEM, TEM, HRTEM, SAED, XPS and EDX techniques were used to characterize the material. The Na/Na₂Ti₃O₇ cell displayed a charge capacity of 177 mA h g⁻¹ at 0.1 C rate. High rate and long term cyclic performance at different rates showed relatively stable storage capacities. Surprisingly, if the lower cut-off voltage is altered, the appearance of a new charge plateau is seen, with no apparent change in the discharge behaviour. The kinetics of sodium insertion and extraction are discussed utilizing CV and EIS techniques. We also report the sodium chemical diffusion coefficient of the Na₂Ti₃O₇/CB electrode estimated using GITT.