Improving battery safety by reducing the formation of Li dendrites with the use of amorphous silicon polymer anodes

摘要

To provide safe lithium-ion batteries (LIBs) at low cost, battery materials which lead to reduced Li dendrite formation are needed. The currently used anode materials have low redox voltages that are very close to the redox potential for the formation of Li metal, which leads to severe short circuiting. Herein, we report that when the three-dimensional amorphous silicon polymers poly(methylsilyne) and poly(phenylsilyne) are used as anode materials, dendritic Li formation on the anode surface is avoided up to a practical current density of 10 mA·g⁻¹ at 5 °C. Equally as significant, poly(methylsilyne) and poly(phenylsilyne) are capable of reacting with 0.45 and 0.9 Li atoms per formula unit, respectively, at an average voltage of approximately 1.0 V, affording reversible capacities of 244 mAh·g⁻¹ and 180 mAh·g⁻¹. Moreover, noteworthy is the fact that polysilynes are suitable for practical applications because they can be prepared through a simple and low-cost process and are easy to handle.