Novel Anodic Material Sourced from Biomass Based on Amorphous Carbon Doped with Aluminum as an Efficient Alternative for Next-Generation Lithium-Ion Batteries

This article focuses on the synthesis and characterization of an amorphous carbon derived from spent coffee grounds converted into a porous amorphous carbon (Cp1) by carbonization up to 900 °C and subsequently combined with aluminum via mechanochemical treatment to obtain the composite Al@Cp1. Powder X-Ray diffraction, Raman spectroscopy, and X-Ray photoelectron spectroscopy indicate turbostratic carbon domains (ID/IG ≈ 1.04) and an Al–O/Al–OH surface layer (Al2O3/Al(OH)3) with a minor metallic Al contribution. Electrochemical performance in Li half-cells was evaluated by cyclic voltammetry, galvanostatic cycling, rate capability tests, and electrochemical impedance spectroscopy. At 0.02 A g−1, Al@Cp1 delivers 212.1 mAh g−1, compared with 83.0 mAh g−1 for Cp1, with an initial coulombic efficiency of ~44%. Across increasing current densities, Al@Cp1 retains higher reversible capacities than Cp1 and shows stable cycling over extended tests (>160 cycles). Impedance analysis indicates a reduced interfacial/charge transfer resistance after electrode conditioning, consistent with interfacial stabilization by the Al-containing surface layer. These results demonstrate a simple, scalable route to upgrade coffee waste carbon into a higher-performance lithium-ion battery anode through mechanochemical interfacial engineering.