Ternary Anode Design for Sustainable Battery Technology: An Off-Stoichiometric Sn/SnSiO_x+2@C Composite Recycled from Biomass

Recycling of environmentally benign, highly abundant mineral resources and low-cost biomass for electrodes is urgently needed for the sustainable integration of energy storage devices. In the present study, we propose a rational design of a ternary composite by integrating Sn nanoparticles, a glass-phase SnSiO_x+2 matrix, and a biomass deriving N-doped carbon framework via a one-pot, scalable annealing process. The synergistic effect of reversible Li⁺ storage properties originates from the complementary functionalities of each component: abundant functional groups grafted on the processed biomass anchor the metallic precursors for intimate coupling of the electroactive components, and the biomass-derived carbon framework serves as a conductive substrate for the ultrasmall Sn particles calcinated from the off-stoichiometric precursor ratio while glass-phase SnSiO_x+2 accommodates the volume expansion of the Sn–Li alloy. The Sn/SnSiO_x+2@C-650 composite anode displays an overall satisfactory cycle performance: the high areal capacity of 1.68 mA h cm^–2 with average Columbic efficiency higher than 99% at 0.2 mA cm^–2 and rate behavior up to 4 mA cm^–2 are simultaneously realized in the half cell. We further establish a prototype full cell by pairing the Sn/SnSiO_x+2@C-650 anode with the modified LiMn₂O₄ cathode: a remarkable cycling stability is maintained for 50 cycles with high gravimetric/volumetric energy densities. This biomass-templated strategy demonstrates a precise control over the structural and compositional features of a multinary composite for next-generation batteries.