Synthesis of Na₂Ti₃O₇–based anode for sodium-ion battery using solid state reaction method

Na₂Ti₃O₇-based anode for sodium-ion battery was synthesized through solid-state reaction of high purity Na₂CO₃ and TiO₂. The dry and wet mixing by using ethanol assistance were used to compare the effects on their properties. Simultaneous Thermal Analysis (STA) was carried out to determine the temperature of sintering process. Precusors, both from dry and wet mixing, were sintered at 900 °C for 4 h in air. The structure and phase of the sintered samples were characterized by X-ray diffraction (XRD), while the particle size was determined using a particle size analyzer (PSA). The samples were then assembled into coin cells for performance test purposes. The electrochemical processes of all of samples were examined using an automatic battery cycler system. It is shown that ethanol assisted-wet process did not decrease the sintering temperature but it decreased the particle size of samples. Phase analysis showed that the phases for both treatments are Na₂Ti₃O₇ and Na₂Ti₆O₁₃, and they had a high crystalinity. Cyclic voltammetry shows that all samples have an unbalanced pair of redox peaks and show formation SEI layers. (paper)