Lithium Dendrite Formation on a Lithium Metal Anode from Liquid, Polymer and Solid Electrolytes

Abstract

Lithium metal is the most attractive anode material for batteries because of its high specific capacity (3861 mAh g −1 ) and low negative potential (−3.04 V vs. NHE). However, lithium dendrite growth during lithium deposition leads to serious safety problems and poor cycling performance. The conventional liquid electrolyte used in lithium-ion batteries results in significant lithium dendrite formation at room temperature and a high current density. Thus, there has been much research effort to achieve the suppression of lithium dendrite formation. Recently, a new class of non-aqueous liquid electrolyte with a high concentration of lithium salts, such as solvated ionic liquid and solvent-in-salt electrolytes, has been reported to suppress lithium dendrite formation. Solid polymer electrolytes have been known to suppress lithium dendrite formation; however, the low lithium ion conductivity and high interface resistance between lithium and the polymer electrolyte at room temperature limits their use for conventional batteries. The interface resistance was significantly decreased by the addition of an ionic liquid into a polymer electrolyte and lithium dendrite formation was suppressed. A theoretical analysis predicted that if a homogenous solid electrolyte with a shear modulus of 6 GPa was obtained, then the lithium dendrite problem would be solved. However, some lithium conducting solid electrolytes such as Li 7 La 3 Zr 2 O 12 still exhibit lithium dendrite formation. In this review, we introduce the recent status of lithium dendrite formation on lithium metal in contact with liquid, solid polymer, and solid electrolytes.

Current limit diagrams for dendrite formation in solid-state electrolytes for Li-ion batteries

“…The shear modulus of cubic LLZO is approximately 60 GPa, while Li metal has a modulus of ~4 GPa [11]. However, dendrite formation has been observed in cubic LLZO at current densities> 0.5 mA cm -2 [8,9,[12][13][14][15][16][17].…”

Lithiophilic Silver Coating on Lithium Metal Surface for Inhibiting Lithium Dendrites

“…Li metal is recognized as one of perfect anodes for LIBs owing to its lowest reduction potential (−3.04 V vs. the standard hydrogen potential electrode) and ultrahigh theoretical specific capacity (3,860 mAh g −1 ) (Xu et al, 2014;Yang et al, 2015;Lin et al, 2017;Xue et al, 2019b). Nevertheless, working risks come from the uncontrolled Li dendrites formation and side-reactions of highly active Li with the electrolyte, which will induce Li metal batteries (LMBs) short circuit (Aurbach et al, 2002;Qian et al, 2015;Takeda et al, 2016;Yan et al, 2016;Guo et al, 2017;Sahalie et al, 2019). To settle these problems, great efforts have been devoted to improve the stability of Li metal anode.…”

High Ionic Conductor Member of Garnet‐Type Oxide Li6.5La3Zr1.5Ta0.5O12

“…Oxide solid electrolytes are further classified into glass, glass‐ceramic, and crystalline types. Crystalline solid electrolytes include LISICON, perovskite, β‐alumina with Na + /Li + ion exchange, and garnet types . Li 7– x La 3 Zr 2– x Nb x O 12 , and Li 7– x La 3 Zr 2– x Ta x O 12 ,,,, in which part of Li 7 La 3 Zr 2 O 12 ,, is substituted with niobium or tantalum, has high lithium ion conductivity and a wide potential window.…”