Molten salt assisted synthesis of Si/C nanocomposite derived from palygorskite and sodium alginate for electrochemical lithium storage

Silicon/carbon (Si/C) nanocomposites are considered as one of the most promising anode materials for lithium-ion batteries due to their high capacity and suitable lithiation potential. However, the complex and time-consuming preparation processes of silicon-based nanocomposites and the unexpected silicon carbide generated during high treatment make it difficult to achieve high-performance Si/C nanocomposites for practical applications. Herein, a silicon/carbon nanocomposite is successfully prepared through a facile and eco-friendly molten salt assisted precarbonization-reduction method using palygorskite (PAL) and sodium alginate as raw materials. Based on physical characterizations, it is demonstrated that the sodium alginate plays a key role in the successful preparation of Si/C nanocomposite, which not only boosts uniform embedding of PAL nanoparticles in the carbon matrix but also releases molten sodium salt to suppress the formation of unexpected SiC. When used as an alternative anode material for lithium-ion battery applications, the as-obtained Si/C composite delivers a high reversible specific capacity of 1362.7 mA h g-1 with an initial Coulombic efficiency of 70.3% at a current density of 200 mA g-1 and excellent long-term cycling stability. The findings here provide a facile and eco-friendly molten salt assisted precarbonization-reduction method for high-performance silicon/carbon anode materials.