College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, 361005, Xiamen, China.
College of Materials, Xiamen University, Xiamen Key Laboratory of Electronic Ceramic Materials and Devices, 361005, Xiamen, China.
Nat Commun. 2023 May 19;14(1):2883. doi: 10.1038/s41467-023-38724-x.
The Li metal is an ideal anode material owing to its high theoretical specific capacity and low electrode potential. However, its high reactivity and dendritic growth in carbonate-based electrolytes limit its application. To address these issues, we propose a novel surface modification technique using heptafluorobutyric acid. In-situ spontaneous reaction between Li and the organic acid generates a lithiophilic interface of lithium heptafluorobutyrate for dendrite-free uniform Li deposition, which significantly improves the cycle stability (Li/Li symmetric cells >1200 h at 1.0 mA cm) and Coulombic efficiency (>99.3%) in conventional carbonate-based electrolytes. This lithiophilic interface also enables full batteries to achieve 83.2% capacity retention over 300 cycles under realistic testing condition. Lithium heptafluorobutyrate interface acts as an electrical bridge for uniform lithium-ion flux between Li anode and plating Li, which minimizes the occurrence of tortuous lithium dendrites and lowers interface impedance.
金属锂因其高理论比容量和低电极电位而成为理想的阳极材料。然而，其在碳酸盐基电解液中的高反应性和枝晶生长限制了其应用。为了解决这些问题，我们提出了一种使用全氟丁酸的新型表面改性技术。在原位，锂与有机酸之间发生自发反应，生成亲锂界面的氟代丁二酸锂，实现无枝晶的均匀锂沉积，显著提高了循环稳定性（在传统碳酸盐基电解液中，Li/Li 对称电池 >1200 h，电流密度为 1.0 mA cm）和库仑效率（>99.3%）。在实际测试条件下，这种亲锂界面还使全电池在 300 次循环后保持 83.2%的容量保持率。氟代丁二酸锂界面作为 Li 阳极和镀 Li 之间均匀锂离子通量的电桥，最大限度地减少了曲折锂枝晶的出现，并降低了界面阻抗。
