Biomass-Derived 3D Interconnected Porous Carbon-Encapsulated Nano-FeS2 for High-Performance Lithium-Ion Batteries

The application of earth-abundant materials is strategically important for industrial manufacture. Utilizing the gelatinization and metallic complexation properties of lotus rhizome starch, a FeS2/lotus rhizome starch-derived carbon (LRSC) composite was prepared with ultrafine FeS2 particles encapsulated in hierarchically porous carbon. The abundant interconnected macropores and micropores in the LRSC can provide diffusion channels for ions and sufficient space for the volume change of FeS2. Besides, a continuous interconnected carbon matrix remarkably enhances the electrical conductivity of FeS2. Therefore, the hierarchically porous carbon-stabilized FeS2 exhibits significantly improved cycling performance compared to pristine FeS2 and FeS2 combined with glucose-pyrolyzed carbon. The electrochemical capacity of the FeS2/LRSC composite is 923.5 mA h g–1 with a capacity retention of 90.2% after 100 cycles at 0.5 A g–1, which is much higher than that of pristine FeS2 (54.6%) and FeS2/C (32.6%). This work offers an approach for designing cost-effective and high-performance electrodes for lithium-ion batteries.