High-performance amorphous silicon - copper composite film anode for lithium-ion batteries with superior cycle stability and conductivity

With the continuous improvement of performance requirements for lithium-ion batteries, developing a high-volume stable anode has become a research priority. Amorphous silicon as a potential anode material for Li-ion batteries has a high theoretical specific capacity, but suffers from poor electrical conductivity and large volume expansion. Copper is renowned for its remarkable electrical conductivity and robust mechanical strength. Harnessing these exceptional properties, we can effectively improve the performance of silicon anodes. Through the magnetron sputtering method, an amorphous silicon - copper composite film anode has been successfully fabricated.

As a new type of anode material for lithium-ion batteries, the amorphous silicon-copper composite film has a first coulombic efficiency of 83.30 % at a current density of 420 mA/g and a reversible capacity retention rate of 95.63 % for 100 to 500 cycles. The volume expansion rate after 500 cycles is 176.9 %. The equivalent resistance of the composite film is about 136 Ohms, and the composite film has the advantages of high coulombic efficiency, good cycle stability, and good electrical conductivity, which provides a new idea and way to improve the performance of lithium-ion batteries.