METHOD FOR PRE-SODIATION OF NEGATIVE ELECTRODE, PRE-SODIATED NEGATIVE ELECTRODE, AND LITHIUM SECONDARY BATTERY COMPRISING SAME

A method for pre-sodiation of a negative electrode, including the steps of: interposing a separator between a sodium ion-supplying metal sheet and a negative electrode to prepare a simple cell; dipping the simple cell in an electrolyte for pre-sodiation; and electrochemically charging the simple cell dipped in the electrolyte for pre-sodiation to carry out pre-sodiation of the negative electrode wherein the electrochemical charging is carried out while the simple cell is pressurized under a pressure of from 100 kPa to 1,000 kPa. A pre-sodiated negative electrode is also disclosed, including: a current collector; a negative electrode active material layer on at least one surface of the current collector. The negative electrode active material layer includes a negative electrode active material; and a coating layer on the surface of the negative electrode active material layer. The coating layer includes Na-carbonate and Na.