Gelatin and sodium alginate derived carbon/silicon composites as high-performance anode materials for lithium-ion batteries†

The volume expansion and poor conductivity greatly limit the application of silicon as an anode for lithium-ion batteries. Although nanocrystallization of silicon and its surface carbon coating can be improved to some extent, the serious problems of particle aggregation and structural instability have not been effectively solved. In this paper, gelatin and sodium alginate (GE + SA) derived carbon/silicon composites are successfully prepared by a liquid-phase method, the freeze-drying technique, and heat treatment. Si nanoparticles (NPs) are uniformly encapsulated in a three-dimensional network of N-doped carbon that is enriched with a rich pore structure. The reversible capacity of the particular Si@C composite electrode was maintained at 580 mA h g⁻¹ after 300 cycles at a current density of 1 A g⁻¹, showing good cycling stability. Meanwhile, the anode also has excellent rate performance with reversible capacities of 2230, 1458, 1101, and 686.6 mA h g⁻¹ at current densities of 0.1, 0.5, 1, and 2 A g⁻¹, respectively. The GE + SA derived carbon/silicon composites effectively solve the problems of particle aggregation and an unstable carbon/silicon interface structure and can become candidates for anode materials in lithium-ion batteries.