HIGH CAPACITY ANODE MATERIALS FOR LITHIUM ION BATTERIES

摘要

High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

主权项

1. A lithium ion battery comprising a positive electrode comprising a cycle-able lithium metal oxide, a negative electrode, a separator between the positive electrode and the negative electrode and supplemental lithium distinct from lithium associated with the lithium metal oxide and supplemental to cycling lithium supplied by the lithium metal oxide, the supplemental lithium being in an amount corresponding to about 2.5% to about 35% of the negative electrode capacity, wherein the negative electrode comprises an active material comprising a silicon-carbon composite material, the active material having a tenth cycle specific capacity of at least about 1000 mAh/g at a rate of C/3 and wherein the supplemental lithium is in the form of electroactive lithium or at least a portion of an SEI layer.