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Silicon (Si) has been considered as one of the most promising anode material for the next generation lithium-ion batteries (LIBs) with high energy densities, due to its high theoretical capacity, abundant availability and environmental friendliness. However, silicon materials with low intrinsic electric and ionic conductivity suffer from huge volume variation during lithiation/delithiation processes leading to the pulverization of Si and subsequently resulting in severe capacity fading of the electrodes. Coupling of Si with carbon (C) realizes a favorable combination of the two materials properties, such as high lithiation capacity of Si and excellent mechanical and conductive properties of C, making silicon/carbon composite (Si/C) ideal candidates for LIBs anodes. In this review, recent progresses of Si/C materials utilized in LIBs are summarized in terms of structural design principles, material synthesis methods, morphological characteristics and electrochemical performances by highlighting the material structures. The mechanisms behind the performance enhancement are also discussed. Moreover, other factors that affect the performance of Si/C anodes, such as prelithiation, electrolyte additives, and binders, are also discussed. We aim to present a full scope of the Si/C-based anodes, and help understand and design future structures of Si/C anodes in LIBs.

Modified spherical graphite/silicon/flake graphite/disordered carbon (SG/Si/C) composite is successfully synthesized by using nano-silicon, flake graphite (FG), modified spherical graphite (SG) and citric acid as raw materials via liquid solidification and subsequent pyrolysis. The material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and electrochemical measurement. The morphology observation shows a core–shell structure with silicon/carbon material as the shell and SG particles as the core. SG/Si/C composites display a good cycle performance with capacity retention of 86% after 50 cycles under a current density of 100 mA g −1 , and also exhibit an excellent cycling performance at higher current densities of 200 mA g −1 and 300 mA g −1 . The available raw materials availability and simple synthesis process promote the as-prepared SG/Si/C materials a promising anode for commercial use.

Silicon/silica (Si/SiO 2 ) composite is prepared directly from irregular micro-silica via mechanical milling followed by modified magnesiothermic reduction process. After that, phenolic resin is introduced as carbon source to fabricate the silicon/silica@carbon (Si/SiO 2 @C) composite. The structure of the composite is revealed by x-ray diffraction (XRD). SEM and TEM observations reveal that the micro-silica particles are broken into submicron scale and part of the silica particles are reduced to silicon by Mg reduction. When evaluated as an anode material for Li-ion batteries, the electrochemical performance of the composite is good. At 50 mA g − 1 , the Si/SiO 2 @C (50 wt.% C) sample exhibits a high initial charge capacity of 685.8 mAh g − 1 . After 100 cycles, it retains reversible capacity of 482 mAh g − 1 . The composite also shows superior rate performance. At 500 mA g − 1 , it can deliver high reversible capacity of 462.3 mAh g − 1 . Considering the facile preparation and low-cost of raw material, the prepared Si/SiO 2 @C composite holds promise in practical Li-ion batteries.