Replacing lithium with a Si anode is a very promising route for the development of all-solid-state batteries (ASSBs) to eliminate the uncontrolled growth of Li dendrites. However, the Si anode still undergoes low electric conductivity and severe volume changes during cycling leading to poor interfacial stability against solid electrolytes. Herein, we report an integrated anode of silicon/ carbon-nanotubes/carbon (Si/CNTs/C) for the stable operation of sulfide-based ASSBs. The in situ synthesized Si/CNTs/C from Mg 2 Si reacting with CaCO 3 in the presence of a ferrocene catalyst for CNT growth exhibits a similar ″reinforced concrete″ structure, where CNTs provide a mechanical stable scaffold for Si particle embedding. In this composite, CNTs act as a ″reinforcing bar″ fixing Si active particles tightly, which not only maintain good interfacial contact between Si and Li 6 PS 5 Cl components but also alleviate the volume expansion of Si and prevent the lithium-ion channel of Li 6 PS 5 Cl from being destroyed. As the anode for ASSBs, the reversible capacity of Si/CNTs/C was 1226 mA h g −1 after 50 cycles at 50 mA g −1 . This study provides an idea for the application of Si-based materials in ASSBs.

The Si/C anode is one of the most promising candidate materials for the next-generation lithium-ion batteries (LIBs). Herein, a silicon/carbon nanotubes/carbon (Si/CNTs/C) composite is in situ synthesized by a one-step reaction of magnesium silicide, calcium carbonate, and ferrocene. Transmission electron microscopy reveals that the growth of CNTs is attributed to the catalysis of iron atoms derived from the decomposition of ferrocene. In comparison to a Si/C composite, the cycle stability of the Si/CNTs/C composite can obviously be improved as an anode for LIBs. The enhanced performance is mainly attributed to the following factors: (i) the perfect combination of Si nanoparticles and in situ grown CNTs achieves high mechanical integrity and good electrical contact; (ii) Si nanoparticles are entangled in the CNT cage, effectively reducing the volume expansion upon cycling; and (iii) in situ grown CNTs can improve the conductivity of composites and provide lithium ion transport channels. Moreover, the full cell constructed by a LiFePO4 cathode and Si/CNTs/C anode exhibits excellent cycling stability (137 mAh g–1 after 300 cycles at 0.5 C with a capacity retention rate of 91.2%). This work provides a new way for the synthesis of a Si/C anode for high-performance LIBs.

The excessive emission of carbon dioxide (CO2) poses a serious threat to the sustainable development of human beings. The efficient conversion of CO2 into high-value-added chemicals is of great significance for solving the greenhouse effect and energy crisis. Herein, a new strategy is proposed to turn CO2 into Si/C/SiC composites through a one-step ball-milling reaction with Mg2Si at room temperature. Moreover, mesophase carbon microspheres (MCMB) are introduced into reactants to prepare Si/C/SiC@MCMB composites for possible commercial application. This method realizes the synchronous formation of Si, C, and SiC with a tight interfacial contact at room temperature, which enhances the electronic conductivity and structural stability of Si/C. It is found that the addition of MCMB greatly restricts the formation of SiC inactive phase and leads to a thin lamellar structure for lithium storage. When evaluated as a lithium-ion battery anode, the Si/C/SiC@MCMB composites exhibit superior cycling stability and rating performance. This room temperature synthesis strategy has the advantages of low cost, simple operation process, and easy scalable production, which not only provide a new route to turn CO2 into a benefit but also provide a new way for the design and synthesis of high-capacity Si/C anodes.

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Attributed to high theoretical capacity and abundant reserves, Si/C anodes have been commercialized in lithium-ion batteries (LIBs). However, the shortcomings of poor interfacial compatibility, low rate performance, and bad stability remain to be overcome. In this paper, a facile method for the synthesis of silicon/iron oxide/carbon (Si/Fe3O4/C) composites by ball-milling in a supercritical carbon dioxide (scCO2) fluid medium is proposed. This method utilizes the diffusion characteristics, extremely low viscosity, and excellent mass transfer properties of supercritical fluids. Under the infiltration of an scCO2 fluid, mesophase carbon microspheres (MCMB) are exfoliated into graphite flakes and achieve good interfacial fusion with silicon and Prussian blue during ball-milling. The Prussian blue is transformed into Fe3O4 by subsequent heat treatment under a nitrogen atmosphere, and Fe3O4 introduced in this way enhances the lithium-storage capacity, cycling stability, and rate performance significantly of Si/C anodes. As an anode for LIBs, the reversible capacity of Si/Fe3O4/C reaches 1363 mA h g–1 after 600 cycles at 1 A g–1. This study provides an idea for the design and fabrication of Si-based anode materials with high capacity and long cycle life.