Ion conductor with high room-temperature ionic conductivity and preparation method thereof

A preparation method of a transition metal silicate ion conductor with high ionic conductivity, wherein the preparation method is performed by sintering using a solid phase method, specifically comprising following steps:

• 1) preparing a precursor, comprising
• preparing a precursor with a transition metal salt, a sodium salt, and ethyl orthosilicate as raw materials, wherein a molar ratio of sodium atoms in the sodium salt to metal atoms in the transition metal salt does not exceed 2, and a molar ratio of sodium atoms in the sodium salt to silicon atoms in the ethyl orthosilicate does not exceed 2;
• 2) making a solid phase sintered, comprising
• transferring the precursor into a porcelain boat, and pre-sintering the precursor in a vacuum tubular furnace protected by an inert gas at 300˜500 ° C. for more than 5 hours;
• milling a resultant to refine powder particles;
• weighing and tableting powder, wherein a pressure applied is not greater than 100 MPa, and the pressure is maintained for 3˜5 minutes, to obtain a precursor sheet with a thickness not more than 3 mm;
• transferring the precursor sheet into a porcelain boat, and finally sintering the precursor sheet in the vacuum tubular furnace protected by an inert gas for more than 8 hours, at a sintering temperature of 500˜900° C., wherein the heating and cooling rates do not exceed 2° C. per minute, so as to obtain a crystalline or amorphous transition metal silicate sodium ion conductor with high ionic conductivity;
• and
• 3) performing ion exchange, comprising
• using an ion exchange method to replace Na in an obtained transition metal silicate sodium ion conductor with other metal ions, so as to prepare other alkali metal or alkaline earth metal ion conductors, wherein ion exchange can be performed by a method comprising electrochemical exchange, molten salt exchange, and solution exchange, wherein the electrochemical exchange is achieved by charging or discharging the obtained sodium ion conductor with different metal anodes, so that other metal ions replace Na sites;
• the molten salt exchange is achieved by to immersing the obtained sodium ion conductor into a molten salt containing different metal ions, and carrying out ion exchange with different chemical potentials;
• and the solution exchange method comprises immersing the obtained sodium ion conductor into a solution of different metal ions, and carrying out ion exchange by concentration differences.