Methods for preparing negative electrodes for electrochemical cells

A method for preparing an electrode assembly for an electrochemical cell that cycles lithium ions, the method comprising:

• applying a potential to a first assembly comprising a first electrode and an aqueous electrolyte comprising a lithium salt and having a temperature greater than or equal to about 10° C. to less than or equal to about 25° C., wherein the first assembly is physically separated from a second assembly by a lithium ion-conducting separator, the second assembly comprising a second electrode and a non-aqueous electrolyte, and wherein as the potential is applied the lithium salt disassociates forming cations and anions;
• and
• forming the electrode assembly as the cations move from the first assembly through the lithium ion-conducting separator and plate onto the second electrode to form a lithium film.

A method for preparing an electroactive material for an electrochemical cell that cycles lithium ions, the method comprising:

• applying a potential to a first assembly comprising a first electrode and an aqueous electrolyte comprising a lithium salt and having a temperature greater than or equal to about 10° C. to less than or equal to about 25° C., wherein the first assembly is physically separated from a second assembly by a lithium ion-conducting separator, the second assembly comprising a second electrode, a non-aqueous electrolyte, and a precursor electroactive material, and wherein as the potential is applied the lithium salt disassociates forming cations and anions;
• and
• forming the electroactive material as the cations move from the first assembly through the lithium ion-conducting separator and interact with the precursor electroactive material.