Phased introduction of lithium into the pre-lithiated anode of a lithium ion electrochemical cell

Abstract

The present invention relates to a method for combining anode pre-lithiation, limited-voltage formation cycles, and accelerating aging via heated storage to maximize specific capacity, volumetric capacity density and capacity retention of a lithium-ion electrochemical cell.

What is claimed: 
     
         1 . A process of maximizing specific capacity and capacity retention of a lithium ion cell comprising: a) pre-lithiating an anode; b) assembling the anode, a cathode, a separator and electrolyte into a sealed cell; c) charging the cell to a voltage above that of electrolyte reduction but below that voltage that would violate the anode maximum safe lithium capacity; d) discharging or partially discharging the cell; and e) charging the cell to the normal full voltage. 
     
     
         2 . A process as in  claim 1 , where the cell is discharged and the partial charge step is repeated, preferably at incrementally higher voltages to stimulate further SEI loss. 
     
     
         3 . A process as in  claim 1 , where an elevated temperature is applied to the cell after the initial partial charge for ½ to 7 or more days. 
     
     
         4 . A process as in  claim 1 , where cell specific capacity and volumetric capacity density are increased. 
     
     
         5 . A process as in  claim 1 , where cell capacity retention is increased. 
     
     
         6 . A process as in  claim 1 , in which the formation cycles are performed at elevated temperatures. 
     
     
         7 . A process of maximizing specific capacity and capacity retention of a lithium ion cell comprising: a) pre-lithiating an anode; b) assembling the anode, a cathode, a separator and electrolyte into a sealed cell; c) heating the cell to an elevated temperature; d) charging the cell to a voltage above that of electrolyte reduction but below that voltage that would violate the anode maximum safe lithium capacity; e) optionally discharging the cell and repeating the partial charge step above, possibly at incrementally higher voltages to stimulate further SEI loss; f) optionally discharging the cell; and g) charging the cell to the normal full voltage. 
     
     
         8 . A process as in  claim 7 , where cell specific capacity and volumetric capacity density are increased. 
     
     
         9 . A process as in  claim 7 , where cell capacity retention is increased. 
     
     
         10 . A process as in  claim 7 , in which an elevated storage step is used prior to step g. 
     
     
         11 . A process of maximizing specific capacity and capacity retention of a lithium ion cell comprising: a) an anode; b) assembling the anode, a cathode, a separator and electrolyte into a sealed cell; c) charging the cell to a voltage above that of electrolyte reduction but below that voltage that would violate the anode maximum safe lithium capacity; d) discharging or partially discharging the cell; and e) charging the cell to the normal full voltage.