Pre-Lithiation of 5V Spinel to Increase Lithium Ion Battery Performance

The next generation of lithium ion batteries requires the use of high capacity cathode and anode material in order to give a high energy battery. Cathode material such as high voltage and energy density LiNi0.5Mn1.5O4 (LNMO) and anode material such as high capacity silicon meet the requirements needed to facilitate the next generation of lithium ion batteries. However, loss of capacity during the first charge and discharge cycle of current Si-graphite composite electrodes (irreversible capacity loss) leads to poor 2nd cycle performance of the electrochemical cell. Compensation of this irreversible capacity loss can be accomplished by the addition of extra lithium into the cathode material for use in lithium consuming cellular processes. Lithiation of the cathode material was accomplished by a sub-zero ammonia reaction using pristine LNMO powder and metallic lithium in an argon environment, then washing the reaction product with anhydrous methanol. Electrodes prepared using lithiated material showed full compensation for the irreversible capacity and better cycling performance when using Si-graphite composite counter electrodes with an efficiency of approximately 98%, 23% more capacity than pristine material, and 42% capacity retention over 100 cycles compared with 29% capacity retention with pristine material