Sustainable Synthesis of Structurally Robust LiNi _1/3 Mn _1/3 Co _1/3 O ₂ Cathodes with Enhanced Electrochemical Performance for Lithium‐Ion Batteries

This study reports on the green synthesis of high‐performance LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111) cathode materials using Actinidia deliciosa (kiwi) extract as a natural chelating and reducing agent. The electrochemical and structural performance of the green‐synthesized NMC (GS‐NMC) is systematically compared with NMCs prepared using sol–gel and solid‐state methods. Structural and surface analyses show that GS‐NMC possesses a highly ordered layered structure with minimal cation mixing, improved crystallinity, and increased surface area. Electron microscopy and Brunauer–Emmett–Teller analyses confirm a refined nanoscale morphology with well‐developed porosity. The X‐ray photoelectron spectroscopy results indicate reduced surface impurities and an optimal distribution of transition‐metal oxides. Electrochemical testing in a three‐electrode aqueous LiOH system demonstrates that GS‐NMC achieves enhanced surface redox activity, low interfacial resistance, and stable pseudocapacitive behavior (≈120 mAh g −1 within a ±1.0 V window) over 1000 cycles. In comparison, sol–gel and solid‐state samples exhibit higher polarization and faster capacity fading. Although tested under aqueous half‐cell conditions, the results show that green synthesis offers a promising route to produce structurally robust and electrochemically responsive NMC materials. The findings also highlight the promise of biogenic synthesis as a sustainable alternative to traditional methods and as a versatile platform for designing high‐performing cathode materials for next‐generation lithium‐ion batteries.