Regulating Li-ion flux distribution via holey graphene oxide functionalized separator for dendrite-inhibited lithium metal battery

The lithium dendrites growth limits the large-scale application of lithium metal batteries (LMBs). Regulating Li+ flux distribution is an effective method to restrain the Li dendrite growth. In this paper, a functional porous composite separator is prepared by simply vacuum filtrating holey graphene oxide onto electrospun polyacrylonitrile (HGO-PAN) fiber membranes. The pores in the basal plane of HGO and nanofluidic channels stacked by the ultra-thin HGO can create more paths for the electrolyte to penetrate, thus improving the ionic conductivity and regulating the uniform Li+ flux distribution during charge and discharge. These advantages enable HGO-PAN separator based Li/LiFePO4 cell to maintain a discharge capacity of 135.7 mAh g(-1) at 2 C after 900 cycles, which is 22.3% higher than that of commercial separator based cell. Meanwhile, the long-term reversible lithium plating/stripping performance (over 800 h) under current density of 1 mA cm(-2) also shows that the lithium dendrites growth is effectively inhibited. We believe that this study offers a promising strategy to inhibit the lithium dendrite growth by separator modification, developing stable, safe and sustainable LMBs.

Automated summary

In this study, the growth of lithium dendrites in lithium metal batteries was effectively inhibited by separator modification, resulting in higher cycling capacity and longer reversible lithium plating/stripping performance.