Sustainable Conversion of Herbal Residues into Heterostructured Carbon Anodes for Fast-Charging Lithium-Ion Batteries

The urgent demand for advanced lithium-ion battery (LIB) anodes with high energy density drives exploration beyond conventional graphite (Gr) and hard carbon (HC). Here, we propose a sustainable strategy to convert discarded Nelumbinis Rhizomatis Nodus (NRN) herbal residues into heterostructured carbon anodes (NRNC) via structural reorganization, synergistically addressing resource valorization and electrochemical optimization. The inherent alkali/alkaline earth metals (K, Ca) in NRN promote the formation of nanographitic domains within the HC matrix, forming a distinct "HC-Gr" configuration. The HC framework enables rapid Li⁺ diffusion and high-capacity storage, while graphite domains facilitate electron transport and reduce charge-transfer resistance. The hierarchical porosity and conductive network improved rate performance (retaining 75.73% of the initial capacity at 6 C) and cycling stability (75.26% capacity retention after 1000 cycles). This work presents a cost-effective and eco-friendly route to prepare high-performance anodes, promoting the transformation of waste into green energy.