Interdispersed silicon–carbon nanocomposites and their application as anode materials for lithium-ion batteries

As an anode material for lithium-ion batteries (LIBs), silicon offers among the highest theoretical storage capacity, but is known to suffer from large structural changes and capacity fading during electrochemical cycling. Nanocomposites of silicon with carbon provide a potential material platform for resolving this problem. We report a spray-pyrolysis approach for synthesizing amorphous silicon–carbon nanocomposites from organic silane precursors. Elemental mapping shows that the amorphous silicon is uniformly dispersed in the carbon matrix. When evaluated as anode materials in LIBs, the materials exhibit highly, stable performance and excellent Coulombic efficiency for more than 150 charge discharge cycles at a charging rate of 1 A/g. Post-mortem analysis indicates that the structure of the Si–C composite is retained after extended electrochemical cycling, confirming the hypothesis that better mechanical buffering is obtained when amorphous Si is embedded in a carbon matrix.

► Silicon–carbon nanocomposites are synthesized via spray pyrolysis of silanes.
► The approach is applicable to synthesis of nanocomposites based on other promising anode materials (e.g. Sn and Fe–Sn).
► Elemental mapping and XRD analysis shows that the Si is amorphous and interdispersed with C.
► Si–C composites manifest high storage capacity and unprecedented cycling stability as LIB anodes.
► Postmortem studies indicate that the composites maintain their structural integrity after extended electrochemical cycling.