Incorporation of lithium oxide into silicon anode via magnetron co-sputtering to optimize structural stability and cycling performance

The advancement and implementation of silicon anode materials are significantly impeded by the considerable volume effect. In this work, lithium oxide (Li₂O) was deposited in conjunction with silicon by magnetron co-sputtering, with the objective of optimizing the electrochemical performance of the Si anode. During the deposition process, a portion of the silicon is oxidized to SiO_x with a lower volume effect. Furthermore, irreversible products, including lithium silicates and lithium oxide, are formed on the surface of the material during the lithiation process, which serve as a protective layer to mitigate the volume effect of the Si anode. Concurrently, the pre-lithiation effect of Li₂O can also enhance its cycling stability. The composite anode prepared by co-sputtering exhibited an initial specific capacity of 2357 mAh g⁻¹ and a capacity retention of 88.41% after 100 cycles at 0.5 C (significantly higher than the capacity retention of 60.68% for the pure Si anode). Moreover, the material showed a rate capacity of 1300 mAh g⁻¹ at 5 C with a good capacity recovery. This study demonstrates that the advanced incorporation of Li₂O into the Si anode by magnetron co-sputtering can effectively enhance its cycling stability while simultaneously providing an effective and feasible method for mitigating the volume effect of Si-based materials.