Chelation-Driven Phosphorus Doping: Upcycling Fungal Industrial Waste into Hard Carbon Anodes

A chelation-driven upcycling strategy is developed to valorize fungal industrial waste into high-performance phosphorus-doped hard carbon anodes. Through electrostatic and hydrogen-bonding synergies, fungal mycelium protein undergoes cocomplexation with phytic acid (PA) to form a homogeneous precursor, which upon carbonization yields P-doped hard carbon (PHC) with a well-modulated microstructure. The optimized PHC exhibits a high specific capacity of 361.52 mAh g –1 at 50 mA g –1, an outstanding initial Coulombic efficiency of 85.81%, and enhanced rate capability. This upcycling success arises from a synergistic mechanism combining chemical modification with microstructural engineering: phosphorus doping expands the interlayer spacing from 0.357 to 0.397 nm, facilitating rapid Na + transport while concurrently improving electronic conductivity; meanwhile, the protein-PA complex modulates the carbonization pathway, generating a closed-pore architecture that effectively mitigates undesirable side reactions. By integrating chelation chemistry with waste valorization, this work establishes a scalable paradigm for converting industrial byproducts into high-value energy materials within a circular economy framework.