Facile synthesis of tunable ultra-thin anodes for long-lasting and high-energy-density lithium metal batteries

Abstract

Thin lithium metal anodes (LMAs) play a crucial role in realizing lithium metal batteries (LMBs) with high-energy–density. However, the commercial production of thin lithium anode continues to face challenges in manufacturing complexities, inadequate reversible capacity and unstable cyclability. Herein, we show a facile and effective strategy to produce ultra-thin LMAs with tunable thickness (10 ∼ 50 μm), in which the Li-Ag alloy is in-situ formed and uniformly loaded on the cellulose-derived carbon supported reduced graphene oxide (CC-rGO). Density functional theory (DFT) calculations reveal that the Li-Ag alloy has strong adsorption energy and minimal energy barrier for Li diffusion, which can effectively meliorate Li transfer and homogeneous deposition. Due to the advantages of the synergistic effect of Li-Ag alloy modification, the elaborate-designed ultra-thin and 3D structure, the CC-rGO/LixAgy/Li anode facilitates the acceleration of Li-ion transport kinetics, reduce the nucleation barrier and offer adequate active sites, thereby improving the electrochemical characteristics. The CC-rGO/LixAgy/Li symmetric cell exhibits stably Li plating/stripping for 5000 h at 1 mA cm−2. When matched with LiFePO4 cathode, the full cell delivers remarkable cycling reversibility for 900 cycles at 3C and the negative/positive capacity (N/P) ratio can be down to 1.18. More impressively, the pouch cell reveals an excellent flexibility with maintaining more than 80 % capacity over 80 cycles at 0.3C in folded states. This study provides a promising avenue to developing viable high-energy–density LMBs.