A Polyborosiloxane Binder for Silicon Battery Anodes in Lithium-Ion Batteries

Harnessing silicon (Si) as the anode material in lithium-ion batteries offers the possibility of a nearly ten-fold capacity increase over traditional graphite anodes. However, the 300% volume expansion and contraction upon charging and discharging hinders its practical use due to a significant loss in capacity with cycling. Unique geometric arrangements of Si particles, as well as modifications of polymer binder, have resulted in advances in capacity retention over time, but many modifications are cost-prohibitive for producing a commercially viable electrode. Our strategy to minimize the loss in capacity retention of this high-capacity anode material involves the utilization of a viscoelastic cross-linked polysiloxane polymer binders. This presentation will discuss the mechanical properties and cycling characteristics of the electrodes prepared with this binder and comparable polymers. A highlight of our progress is a retention of charge capacity over >100 cycles. In addition to the retention of capacity, we highlight the low cost and simple synthesis of this polymer binder.