The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

Abstract

Lithium metal has shown great promise as an anode material for high-energy storage systems, owing to its high theoretical specific capacity and low negative electrochemical potential. Unfortunately, uncontrolled dendritic and mossy lithium growth, as well as electrolyte decomposition inherent in lithium metal-based batteries, cause safety issues and low Coulombic efficiency. Here we demonstrate that the growth of lithium dendrites can be suppressed by exploiting the reaction between lithium and lithium polysulfide, which has long been considered as a critical flaw in lithium-sulfur batteries. We show that a stable and uniform solid electrolyte interphase layer is formed due to a synergetic effect of both lithium polysulfide and lithium nitrate as additives in ether-based electrolyte, preventing dendrite growth and minimizing electrolyte decomposition. Our findings allow for re-evaluation of the reactions regarding lithium polysulfide, lithium nitrate and lithium metal, and provide insights into solving the problems associated with lithium metal anodes.

A Review of Solid Electrolyte Interphases on Lithium Metal Anode

“…Free‐standing graphene foam provides several promising features as underneath layer for Li anode, including (1) relative larger surface area than 2D substrates to lower the real specific surface current density and the possibility of dendrite growth, (2) interconnected framework to support and recycle dead Li, and (3) good flexibility to sustain the volume fluctuation during repeated incorporation/extraction of Li. The synergy between the LiNO 3 and polysulfides provides the feasibility to the formation of robust SEI in an ether‐based electrolyte 176, 177. The efficient in situ formed SEI‐coated graphene structure allows stable Li metal anode with the cycling Coulombic efficiency of ≈97% with high safety and efficiency performance, which is with a low resistance of 19.65 Ω (29.10 Ω for Cu foil based Li metal anode) and high ion conductivity of 5.42 × 10 −2 mS cm −1 (2.33 × 10 −2 mS cm −1 for Cu foil based Li metal anode).…”

A Dual‐Salt Gel Polymer Electrolyte with 3D Cross‐Linked Polymer Network for Dendrite‐Free Lithium Metal Batteries

“…For the Li metal anode in liquid electrolyte, the COR (286.6 eV)38, 39 and COOR (288.8 eV)38, 39 groups (Figure 5a) emerge during the SEI formation. After cycling, there are a lot of CO 3 2− (289.5 eV)36, 40 and CF 3 (293.1 eV)38, 39 groups (Figure 5c) on the surface of Li metal anode because of the decomposition of carbonate solvents and Li salt anions.…”

“…For the Li metal anode in liquid electrolyte, the COR (286.6 eV)38, 39 and COOR (288.8 eV)38, 39 groups (Figure 5a) emerge during the SEI formation. After cycling, there are a lot of CO 3 2− (289.5 eV)36, 40 and CF 3 (293.1 eV)38, 39 groups (Figure 5c) on the surface of Li metal anode because of the decomposition of carbonate solvents and Li salt anions. Seen from the F 1s spectra (Figure 5b), the LiF (684.9 eV) and Li x PO y F z (687.4 eV)41, 42 can be observed during the SEI formation, which are the decomposition products of Li salt anions.…”

“…Seen from the F 1s spectra (Figure 5b), the LiF (684.9 eV) and Li x PO y F z (687.4 eV)41, 42 can be observed during the SEI formation, which are the decomposition products of Li salt anions. After cycling, the amount of LiF and Li x PO y F z change significantly and a lot of CF 3 (689.1 eV) groups emerge (Figure 5d), indicating the decomposition of LiTFSI and LiPF 6 during the cycling 38, 43. Consequently, in the LMB using liquid electrolyte, the reduction products of electrolyte markedly increase in the SEI layer after cycling, elucidating the SEI layer is too fragile to protect Li metal anode.…”

Passivation of Lithium Metal Anode via Hybrid Ionic Liquid Electrolyte toward Stable Li Plating/Stripping

“…However, these strategies cannot change the breakage/repair mechanism of SEI layer, and significantly improve the Coulombic efficiency of Li plating/stripping. In addition, optimization of electrolyte using additives,8 high concentrated electrolytes,9 and ionic liquid electrolytes10 can enhance the stability of SEI layers, and can improve the Coulombic efficiency of Li plating/stripping. However, the electrolyte additives are consumed during the SEI formation and thus affect the electrochemical performance.…”