An ultraviolet curable silicon/ graphite electrode binder for long-cycling lithium ion batteries

Urushiol monomers, which are used as a new ultraviolet curable binder (Ur Binder), have been directly applied to prepare silicon/graphite electrodes of lithium batteries. Investigations show that the Ur Binder is conducive to the preparation of uniform electrode slurry and the formation of uniform electrode coating layer, which makes a close contact between electrochemical active materials and conductive carbon. Besides that, strong interaction between the polymer of the Ur Binder and silicon powders plays a key role in the long-cycling lithium battery. Lithium coin cells using the Ur Binder achieve a capacity of 603.3 m Ah g−1 and excellent capacity retention of 96.1% after 400 cycles. Even at a high current density of 2.0C, the coin cell with the Ur Binder maintains approximately 77.9% of its original capacity (0.2C rate). Notably, slurry containing the Ur Binder can be superimposed on copper foil for coating and curing, which helps to relieve the low capacity limitations of ultraviolet curable silicon/graphite electrodes for commercial applications.