Wang Dongdong, Liu Hongxia, Liu Fang, Ma Guorong, Yang Jian, Gu Xiaodan, Zhou Meng, Chen Zheng
Department of NanoEngineering, University of California San Diego, La Jolla, California 92093, United States.
Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P.R. China.
Nano Lett. 2021 Jun 9;21(11):4757-4764. doi: 10.1021/acs.nanolett.1c01241. Epub 2021 May 26.
Solid-electrolyte interphase (SEI) plays a pivotal role in stabilizing lithium (Li) metal anode for rechargeable batteries. However, electrolyte-derived SEI often suffers from poor stability, leading to Li dendrite growth, consumption of electrolyte, and short cycle life. Here, we report a porous lithiophilic polymer coating induced by phase separation of polyvinylidenefluoride-polyacrylonitrile (PVDF-PAN) blends for stabilizing Li metal anode. Different from single polymer coating, PVDF-PAN blends protective layer with porous structures caused by phase separation can provide effective Li transport channels and regulate uniform Li flux. The lithiophilic functional groups of C≡N and C-F can promote uniform Li deposition and accelerate Li diffusion at the same time during plating/stripping process. As a result, Li||NCM811 full cells using PVDF-PAN coated Li present an apparently improved cycling stability and higher Coulombic efficiency with lean electrolyte (7.5 μL mA h), limited Li supply (N/P ratio = 2.4), and high areal capacity (4.0 mA h cm).
固体电解质界面（SEI）在稳定用于可充电电池的锂（Li）金属阳极方面起着关键作用。然而，由电解质衍生的SEI通常稳定性较差，导致锂枝晶生长、电解质消耗和循环寿命短。在此，我们报道了一种由聚偏氟乙烯 - 聚丙烯腈（PVDF - PAN）共混物相分离诱导的多孔亲锂聚合物涂层，用于稳定锂金属阳极。与单一聚合物涂层不同，由相分离产生的具有多孔结构的PVDF - PAN共混物保护层可以提供有效的锂传输通道并调节均匀的锂通量。C≡N和C - F的亲锂官能团在电镀/剥离过程中可以同时促进锂的均匀沉积并加速锂的扩散。结果，使用PVDF - PAN涂层锂的Li||NCM811全电池在贫电解质（7.5 μL mA h）、有限锂供应（N/P比 = 2.4）和高面积容量（4.0 mA h cm）的情况下，表现出明显改善的循环稳定性和更高的库仑效率。
