Semimicro-size agglomerate structured silicon-carbon composite as an anode material for high performance lithium-ion batteries

A semimicro-size agglomerate structured silicon-carbon (mSi-C) composite is constructed by an aggregation of silicon nanoparticles (∼100 nm) coated with conductive carbon layer through a facile and scalable aerosol-assisted process to be employed as an anode material for lithium-ion batteries (LIBs). As-formed mSi-C composite delivers good electrochemical performances of high reversible capacity (2084 mAh/g) between 0.01 and 1.50 V (vs. Li/Li⁺) at 0.4 A/g, 96% capacity retention (1999 mAh/g) after 50 cycles and good rate capability (906 mAh/g) at 12 A/g. Such good performances can be attributed to 1) unique composite structure which accommodates the stress induced by volume change of silicon during lithiation/delithiation and facilitates ion transport, and 2) conformally formed carbon layer which enhances conductivity of the composite and helps to form a stable SEI layer. In addition, a high tap density (0.448 g/cm³) of mSi-C composite leads to high volumetric capacity (933 mAh/cm³), allowing its practical applications as an anode material towards high performance LIBs.