MoS_(2)纳米片功能化PAN锂金属电池隔膜的制备及锂枝晶抑制作用

Fabrication of MoS_(2)Nanosheets Functionalized PAN Lithium Metal Battery Separator and Its Inhibition of Lithium Dendrite

引导锂离子流的均匀分布可以有效抑制锂枝晶的形成-生长,推动锂金属电池的产业化应用.本文采用化学插层法制备出单层或少层、结构完整的MoS_(2)纳米片,将二维MoS_(2)纳米片喷涂到静电纺聚丙烯腈(PAN)纤维膜上,制得MoS_(2)@PAN复合隔膜.MoS_(2)涂层的引入不仅提高了离子电导率(1.02 mS/cm)、Li+迁移数(0.59)和电解液亲和性,而且降低了复合隔膜的孔径,使其孔径分布均一.这些特性协同作用,调控了通过MoS_(2)@PAN复合隔膜的Li+流分布,促进了Li+在锂金属表面的均匀沉积,抑制了锂枝晶的形成-生长.因此,MoS_(2)@PAN复合隔膜组装的Li/Li电池在1 mA/cm^(2)电流密度下以14 mV的超低过电位可稳定循环长达500 h,循环后的锂金属表面没有明显的枝晶生长.此外,MoS_(2)@PAN复合隔膜组装的LiFePO_(4)/Li电池在2C倍率下循环550次后保持92%的初始容量,表现出更稳定的循环性能.通过隔膜调节Li+通量实现了锂的均匀沉积,为抑制锂枝晶的形成-生长提供了一种可行的策略.

Guiding the uniform distribution of Li+flux can effectively inhibit the formation and growth of lithium dendrites,promoting the industrial application of lithium metal batteries.In this study,MoS_(2)nanosheets with single or few layers,completed structure were prepared by chemical intercalation method,then two-dimensional MoS_(2)nanosheets were sprayed onto electrospun polyacrylonitrile(PAN)fiborus membrane to obtain MoS_(2)@PAN composite separator.The introduction of MoS_(2)coating not only improved ion conductivity(1.02 mS/cm),Li+transfer number(0.59),and electrolyte affinity,but also reduced the pore size of the composite membrane,resulting in a uniform pore size distribution.Synergistic effect of these characteristics regulated the Li+flow through MoS_(2)@PAN separator and promoted the uniform Li deposition on the surface of lithium metal,inhibiting the formation and growth of lithium dendrites.Therefore,the Li/Li symmetric cell with MoS_(2)@PAN separator achieved a stable cycle with a low overpotential of 14 mV for 500 h at 1 mA/cm^(2),and there was no obvious lithium dendrite growth on the Li anode surface after cycling.Moreover,the LiFePO_(4)/Li battery assembled with MoS_(2)@PAN separator maintained an initial capacity of 92%after 550 cycles at 2C,demonstrating more stable cycling performance.This study redistributes the Li+flux through a separator to achieve uniform Li deposition,providing a feasible strategy for suppressing the formation and growth of lithium dendrites.