Suppressing Li dendrite by a guar gum natural polymer film for high-performance lithium metal anodes

Lithium dendrites pose a major hurdle for enhancing the energy density of lithium metal batteries, and the artificial solid electrolyte interface layer offers a potential solution. In this work, a cost-effective and environmentally friendly guar gum film is applied to the artificial protective layer. The guar gum artificial solid electrolyte interface (SEI) layer formed naturally, enriched with -OH and -AOA- groups, displayed exceptional electrochemical stability, and achieved an impressively high transference number of 0.88 for lithium-ion movement. In symmetric cells, the Li@GG-Cu anode displays remarkable cycling performance even during extended periods. This is evidenced by its ability to maintain a surface capacity of approximately 850 h (1 mA cm⁻², 1 mAh cm⁻²). In addition, when utilizing a complete cell setup comprising a LiFPO₄ cathode (weighing 1.5 mg cm⁻²) and anode coated with a guar gum film, the capacity retention of an impressive 96.2% showcases outstanding preservation of battery performance over time even after 700 cycles. This performance surpasses that of a lithium foil electrode (87.1%) and a copper anode with lithium deposition (0%). Our work exhibits a promising material for a novel configuration of artificial SEI, effectively stabilizing lithium metal anode.