From biomass to batteries: the contribution of silicon–carbon composites prepared from high-nitrogen egg whites and micron-sized silica powder to lithium-ion battery performance

Abstract

In this research, we explore the utilization of biomass-derived proteins, specifically from egg whites, as a novel carbon source for crafting silicon/nitrogen-doped carbon composites, aimed at overcoming the significant volume expansion issues associated with silicon electrode materials in lithium-ion batteries (LIBs). Egg whites, known for their high protein content, offer a sustainable reservoir of carbon and nitrogen, essential for enhancing the electrochemical performance of silicon-based electrodes. Leveraging the unique structural transformation induced by whipping egg whites—resulting in a foamy material with distinct properties—we blend this with micron-sized silica powder. This mixture is then subjected to a straightforward carbonization process, yielding silicon–carbon composites enveloped in nitrogen-doped amorphous carbon layers. Our findings demonstrate that these Si–N–PC composites, when used as anodes in LIBs, deliver a commendable reversible capacity of 814 mA h g⁻¹ over 100 cycles at a current density of 1 A g⁻¹. The incorporation of nitrogen-doped carbon layers significantly improves lithium-ion diffusion, mechanical stability, and overall electrochemical performance of the electrode material. This approach not only simplifies the production process but also aligns with environmentally friendly practices. Given these results, we posit that our method could serve as a viable blueprint for the mass production of next-generation energy materials, addressing both performance and sustainability concerns.