Metal–Organic Frameworks‐Derived Mesoporous Si/SiOx@NC Nanospheres as a Long‐Lifespan Anode Material for Lithium‐Ion Batteries

Silicon (Si)‐based anode materials with suitable engineered nanostructures generally have improved lithium storage capabilities, which provide great promise for the electrochemical performance in lithium‐ion batteries (LIBs). Herein, a metal–organic framework (MOF)‐derived unique core–shell Si/SiOx@NC structure has been synthesized by a facile magnesio‐thermic reduction, in which the Si and SiOx matrix were encapsulated by nitrogen (N)‐doped carbon. Importantly, the well‐designed nanostructure has enough space to accommodate the volume change during the lithiation/delithiation process. The conductive porous N‐doped carbon was optimized through direct carbonization and reduction of SiO2 into Si/SiOx simultaneously. Benefiting from the core–shell structure, the synthesized product exhibited enhanced electrochemical performance as an anode material in LIBs. Particularly, the Si/SiOx@NC‐650 anode showed the best reversible capacities up to 724 and 702 mAh g−1 even after 100 cycles. The excellent cycling stability of Si/SiOx@NC‐650 may be attributed to the core–shell structure as well as the synergistic effect between the Si/SiOx and MOF‐derived N‐doped carbon.