Realizing Dendrite-Free Lithium Deposition with a Composite Separator.

Yan, Jun; Liu, Fengquan; Hu, Zhiyu; Gao, Jian; Zhou, Weidong; Huo, Hong; Zhou, Jianjun; Li, Lin · Nano Lett · 2020

basic_science · Level V

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Abstract

A dendrite-free Li deposition strategy is developed with a composite separator of MnCO<sub>3</sub> coated porous polypropylene. Mn<sup>2+</sup> ions are preferentially reduced to form Mn nanoparticles on Li anodes, which helped to reduce the nucleation overpotential and achieve a dendrite-free deposition of Li bulky grains. When MnCO<sub>3</sub> contacts the Li metal anode directly, an <i>in situ</i> artificial solid electrolyte interphase passivating layer was created from the reaction of Li metal, MnCO<sub>3</sub> and liquid electrolyte. Li metal anodes show significantly improved stability for more than 2000 h of plating/stripping in Li||Li symmetric cells. The homemade ultrathin Li films on Cu foils (Li@Cu), obtained by electrochemical Li deposition with PP/MnCO<sub>3</sub> separators, give enhanced cycling stability in LFP||Li@Cu cells. Combined with gel polymer electrolyte, the cycling stability of quasi-solid-state LFP||Li@Cu was further improved. This strategy for dendrite-free deposition via a composite separator provides a low-cost but efficient choice for alkaline metal batteries.