Green Synthesis of SnO 2 /Carbon Composite Anode for Low‐Temperature Lithium‐Ion Batteries

Renewable energy is critical to building a sustainable society, but its true potential can only be unlocked by developing efficient, environmentally friendly energy storage systems. Advances in storage technologies, including cost‐effective and green materials, are quickly becoming the cornerstone of sustainable energy solutions. The most effective battery technology available now is lithium‐ion batteries (LIBs). However, the sustainability of battery material production and the degradation of LIB functionality at subzero temperatures pose significant challenges, highlighting the urgent need for alternative and sustainable low‐temperature (LT) electrode materials. To overcome these issues, a green synthesis approach is proposed to fabricate SnO 2 nanoparticles using an aqueous extract of banana peel, while the leftover peel serves as a carbon precursor to produce a SnO 2 /hard carbon composite. The optimized SnO 2 /hard carbon (7:3) composite was used as the anode and showcased a remarkable reversible capacity of 1110 mAh g −1 at room temperature and retained about 660 mAh g −1 at −20 °C and 100 mA g −1 after 100 cycles, with a capacity of 383 mAh g −1 even at −30 °C. Stable cycling performance was achieved by the synergistic interaction of SnO 2 and hard carbon, which improved lithium‐ion diffusion and mitigated volume expansion. This eco‐friendly and scalable approach shows great promise for developing high‐performance anodes for the next generation of LT LIBs.