Porous Si‐Cu3Si‐Cu Microsphere@C Core–Shell Composites with Enhanced Electrochemical Lithium Storage

Low‐cost Si‐based anode materials with excellent electrochemical lithium storage present attractive prospects for lithium‐ion batteries (LIBs). Herein, porous Si‐Cu3Si‐Cu microsphere@C composites are designed and prepared by means of an etching/electroless deposition and subsequent carbon coating. The composites show a core–shell structure, with a porous Si/Cu microsphere core surrounded by the N‐doped carbon shell. The Cu and Cu3Si nanoparticles are embedded inside porous silicon microspheres, forming the porous Si/Cu microsphere core. The microstructure and lithium storage performance of porous Si‐Cu3Si‐Cu microsphere@C composites can be effectively tuned by changing electroless deposition time. The Si‐Cu3Si‐Cu microsphere@C composite prepared with 12 min electroless deposition delivers a reversible capacity of 627 mAh g−1 after 200 cycles at 2 A g−1, showing an enhanced lithium storage ability. The superior lithium storage performance of the Si‐Cu3Si‐Cu microsphere@C composite can be ascribed to the improved electronic conductivity, enhanced mechanical stability, and better buffering against the large volume change in the repeated lithiation/delithiation processes. Sharing a shell: Porous Si‐Cu3Si‐Cu microsphere@C core–shell composites fabricated by an etching/electroless deposition and subsequent carbon coating show excellent lithium storage performance.