Novel flexible Mn-based carbon nanofiber films as interlayers for stable lithium-metal battery

Abstract

In this work, the novel flexible Mn-based carbon nanofiber interlayers were rationally designed and prepared by electro-blow spinning and carbonization method. Especially, the representative MnS carbon nanofiber (MnS-CNFs) films and MnF2 porous carbon nanofiber (MnF2-PCNFs) film were respectively applied as interlayer to hybridize with Li as composite anode to investigate their application performance. After systematic research, the cyclic stability of interlayer modified LCO-Li batteries (MnS-CNFs: initial capacity of 143 mAh g−1 and retention rate of 70% after 100 cycles, MnF2-PCNFs: initial capacity of 137 mAh g−1 and retention rate of 90% after 100 cycles) were obviously improved when compared with pristine LCO-Li battery (initial capacity of 133 mAh g−1 and retention rate of 45% after 100 cycles) at the current density of 3 mA cm−2. The modified symmetric Li battery exhibits stable Li deposition-stripping behavior without cell short-circuit during 150 cycles. The higher performance of modified battery compared with pure Li metal battery might be attributed to the introduction of flexible Mn-based carbon nanofiber interlayers. On the one hand, the flexible films with self-support and porous structure could act as transitional layer to accommodate the volume expansion of Li metal and facilitate more Li insert into the interior/surface of carbon nanofibers. On the other hand, the 3D interconnected carbon nanofiber skeletons doped MnS and MnF2 could provide more active sites to guide the Li deposition and stripping more sufficient and homogeneous.