Ren Y X, Zeng L, Jiang H R, Ruan W Q, Chen Q, Zhao T S
HKUST Energy Institute, The Hong Kong University of Science and Technology, Clear Water Bay, 999077, Kowloon, Hong Kong SAR, China.
Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, 999077, Kowloon, Hong Kong SAR, China.
Nat Commun. 2019 Jul 19;10(1):3249. doi: 10.1038/s41467-019-11168-y.
A rechargeable lithium anode requires a porous structure for a high capacity, and a stable electrode/electrolyte interface against dendrite formation and polysulfide crossover when used in a lithium-sulfur battery. Here, we design two simple steps of spontaneous reactions for protecting porous lithium electrodes. First, a reaction between molten lithium and sulfur-impregnated carbon nanofiber forms a fibrous network with a lithium shell and a carbon core. Second, we coat the surface of this porous lithium electrode with a composite of lithium bismuth alloys and lithium fluoride through another spontaneous reaction between lithium and bismuth trifluoride, solvated with phosphorous pentasulfide, which also polymerizes with lithium sulfide residual in the electrode to form a solid electrolyte layer. This protected porous lithium electrode enables stable operation of a lithium-sulfur battery with a sulfur loading of 10.2 mg cm at 6.0 mA cm for 200 cycles.
可充电锂负极需要具有多孔结构以实现高容量，并且在用于锂硫电池时需要稳定的电极/电解质界面以防止枝晶形成和多硫化物交叉。在此，我们设计了两个简单的自发反应步骤来保护多孔锂电极。首先，熔融锂与硫浸渍的碳纳米纤维之间的反应形成了具有锂壳和碳核的纤维网络。其次，我们通过锂与五硫化磷溶剂化的三氟化铋之间的另一个自发反应，在该多孔锂电极表面涂覆锂铋合金和氟化锂的复合材料，该复合材料还与电极中残留的硫化锂聚合形成固体电解质层。这种受保护的多孔锂电极能够使硫负载量为10.2 mg/cm²的锂硫电池在6.0 mA/cm²的电流下稳定运行200次循环。
