Layer-by-Layer Assembled Graphite/Silicon/Graphite Anode via Magnetron Sputtering for High-Energy-Density Lithium-Ion...

Silicon is one of the most promising anode materials for next-generation high-energy-density lithium-ion batteries (LIBs), but it suffers from low conductivity and huge volume variation during lithiation/delithiation. In this work, graphite/silicon/graphite hybrid anodes with unique multilayered structures, called SG/Si/SG and SG/(Si/SG)₅, are assembled on copper collectors using magnetron sputtering combined with a coating process. This strategy utilizes the graphite layer to alleviate the volume change of Si and prevent direct contacts of Si with both a current collector and an electrolyte to protect the falling off of the active material from the current collector and to inhibit side reactions. The as-fabricated SG/Si/SG anode has an initial lithiation capacity of 589.4 mAh g^-1 with an initial Coulombic efficiency (ICE) of 86.5%. After 300 cycles at 1C, it maintains a specific capacity of 381.8 mAh g^-1, with a remarkable capacity retention of 102.3%. Furthermore, under a high loading of ∼7.4 mg cm^-2, the SG/(Si/SG)₅ anode exhibits an initial areal capacity of 3.433 mAh cm^-2 (specific capacity of 463.9 mAh g^-1) and an ICE of 89.9%. After 100 cycles at 0.1C, it maintains an areal capacity of 2.024 mAh cm^-2 (specific capacity of 290.2 mAh g^-1), corresponding to a capacity retention of 67.8%. The multilayered carbon-silicon anode, with SG/(Si/SG)_n configuration, should be practically useful for high-energy-density LIBs manufacture.