Surface modification of SiOx film anodes by laser annealing and improvement of cyclability for lithium-ion batteries

Abstract SiOx (x = 0.66, 0.76 and 1.04) film anodes with the different oxygen content were prepared by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) through adjusting SiH4/N2O (R) gas flow ration. The introduction of oxygen can alleviate volume expansion in the discharge/charge process at the expense of cyclic specific capacity. To obtain both higher capacity and cyclically stable SiOx film anodes, KrF excimer laser system operated at λ = 248 nm can induce to form nanoparticles on the surface of SiO0.76 film, which is related to the formation of solid electrolyte interphase (SEI) area during charge/discharge process. The SEI area becomes larger and mechanically robust with increase of laser energy density, which suppresses structural degeneration for giving lithium-ion battery longer cycle life. At the laser energy density of 266 mJ/cm2, SiO0.76 annealed film anode delivers capacity of 1731 mAh/g and capacity retention of 94.8% after 300 cycles, which are much higher than that of as-deposited anode. Increasing laser energy density to 433 mJ/cm2, SiO0.76 film anode shows higher capacity retention of 97.4% after 300 cycles.