Electrospining Machine: TIANXI LIU & LINA WANG JMCA, Donghua University: Alloying Sn-modified Carbon Electrospun Nanofbers for Stable Cycling of Lithium Metal Anode

Background

Lithium metal anode is the most promising candidate for lithium battery upgrading, but the uncontrollable growth of lithium dendrites and infinite volume change during cycling have hindered the practical application of lithium metal anode. In view of this, the team of Prof. Tianxi Liu and Lina Wang at Donghua University constructed a self-supported Sn-modified porous carbon Electrospun Nanofbers skeleton to promote the deposition of dendrite-free Li, forming a lithium-friendly Li5Sn2 alloy to reduce the nucleation overpotential and extend the lifetime and stable cycling stability of Sn/CNF@Li batteries. The related research was published in the journal “Journal of Materials Chemistry A” under the title of “Steady cycling of lithium metal anode enabled by alloying Sn-modified carbon nanofibers”. Materials Chemistry A.

The main point of this paper

1. This study proposes a simple strategy to construct lithium-tin alloy-modified hollow carbon Electrospun Nanofbers self-supporting skeleton (Sn/CNF), which guides the dendrite-free deposition of lithium metal and stabilizes the cycling.

2.Ultrafine Sn nanoparticles are uniformly distributed on the three-dimensional Electrospun Nanofbers skeleton, and in the initial lithiation stage, Sn and Li alloying reaction occurs, in situ generation of Li5Sn2 with lithophilic properties.

3.The alloyed Li5Sn2 as a continuous Li nucleation grains, so that the lithium metal in the low nucleation overpotential deposition, and its rapid charge transfer kinetics also makes Li + carrier homogenization.

4. Meanwhile, the Electrospun Nanofbers skeleton with high specific surface area and good mechanical properties suppresses the volume expansion of Li deposition under high capacity.

How is dendrite-free lithium deposition achieved?

1. Dendrite-free lithium deposition was achieved by using a network of lithophilic tin-modified highly porous carbon Electrospun Nanofbers.

2. The reversible alloying reaction of Sn and Li during the initial lithiation stage induced a uniformly distributed and in situ formed Li-Sn alloy.

3. This thophilic Li5Sn2 alloy provides abundant electrochemical nucleation sites for Li and enhances the charge transfer kinetics, resulting in dendrite-free lithium deposition behavior.

4.In addition, the porous Sn/CNF with high mechanical strength mitigated the volume change during repeated lithium plating and stripping, further promoting dendrite-free lithium deposition.

Originallink: https://doi.org/10.1039/D3TA02379F