Correlating the interface resistance and surface adhesion of the Li metal-solid electrolyte interface

Wang, Michael J.; Sakamoto, Jeff

doi:10.1016/j.jpowsour.2017.11.078

Cited by 94 publications

(78 citation statements)

References 21 publications

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“…Li 2 CO 3 , in particular, is understood to result in a higher interfacial impedance, [18] and as a result, it is common practice to remove this interfacial reaction layer by mechanical polishing inside of a glove box before cell assembly. [30] XPS analysis of polished samples (Figure 1b) reveals that much, but not all, of the carbonate content is indeed removed upon polishing; however, significant LiOH content remains on the surface, which is most likely formed from residual H 2 O present either in the glove box environment or in the polishing paper. In order to further clean the LLZO surface of reaction products, annealing of these samples was carried out in UHV at 80 °C (Figure 1c), which led to removal of LiOH species.…”

Section: Influence Of Surface Preparation On Llzo Surface Chemistrymentioning

confidence: 99%

Dopant‐Dependent Stability of Garnet Solid Electrolyte Interfaces with Lithium Metal

Zhu

Connell

Tepavcevic

et al. 2019

Advanced Energy Materials

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materials are a particularly promising class of solid electrolytes for all-solidstate lithium metal batteries, as they are predicted to have a wide electrochemical stability window, [5,6] can be synthesized with very high density (>97%) [7,8] and, through aliovalent doping, can achieve room temperature Li-ion conductivities as high as ≈1.0 mS cm −1 with negligible electronic conductivity. [9] However, significant fundamental issues remain unresolved for garnet-based all-solid-state batteries, including low accessible current densities, [10] the persistence of Li dendrite formation, [11,12] and perhaps most importantly, ambiguities as to whether the interfaces between LLZO and both Li metal [13,14] and high voltage oxide cathodes [15,16] are stable over extended cycling. Indeed, developing deep understanding of the intrinsic reactivity between solid electrolytes and relevant electrode materials is crucial to developing high voltage solidstate batteries with long lifetimes, as the presence of any significant (electro)chemical reactivity will ultimately lead to premature cell failure during extended cycling.Understanding interfacial stability is an especially challenging issue common to all solid-state battery systems due to the inability of many experimental techniques to adequately interrogate the chemical properties of buried interfaces. Such studies are further complicated when one or both materials at the interface are unstable to exposure to air, water, etc., as Li 7 La 3 Zr 2 O 12 (LLZO) garnet-based materials doped with Al, Nb, or Ta to stabilize the Li + -conductive cubic phase are a particularly promising class of solid electrolytes for all-solid-state lithium metal batteries. Understanding of the intrinsic reactivity between solid electrolytes and relevant electrode materials is crucial to developing high voltage solid-state batteries with long lifetimes. Using a novel, surface science-based approach to characterize the intrinsic reactivity of the Li-solid electrolyte interface, it is determined that, surprisingly, some degree of Zr reduction takes place for all three dopant types, with the extent of reduction increasing as Ta < Nb < Al. Significant reduction of Nb also takes place for Nb-doped LLZO, with electrochemical impedance spectroscopy (EIS) of Li||Nb-LLZO||Li symmetric cells further revealing significant increases in impedance with time and suggesting that the Nb reduction propagates into the bulk. Density functional theory (DFT) calculations reveal that Nb-doped material shows a strong preference for Nb dopants toward the interface between LLZO and Li, while Ta does not exhibit a similar preference. EIS and DFT results, coupled with the observed reduction of Zr at the interface, are consistent with the formation of an "oxygen-deficient interphase" (ODI) layer whose structure determines the stability of the LLZO-Li interface.

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Section: Influence Of Surface Preparation On Llzo Surface Chemistrymentioning

confidence: 99%

Dopant‐Dependent Stability of Garnet Solid Electrolyte Interfaces with Lithium Metal

Zhu

Connell

Tepavcevic

et al. 2019

Advanced Energy Materials

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250

282

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“…Other researchers have also proposed that the interfacial resistance between an electrode and LLZO is not only the source of slow SSB kinetics, but it significantly contributes to short‐circuit failure 20,25–29. Poor contact between lithium metal and LLZO has been reported to cause large interfacial resistance that results in an inhomogeneously distributed current that triggers such failure 19,26,27,30. In this respect, recent studies have attempted to reduce contact resistance by removing surface impurities or introducing an artificial interlayer between the lithium metal and the LLZO, which have led to some improvements 26,27,31–37…”

Section: Introductionmentioning

confidence: 99%

The Role of Interlayer Chemistry in Li‐Metal Growth through a Garnet‐Type Solid Electrolyte

Kim

Jung

Kim

et al. 2020

Advanced Energy Materials

140

130

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Securing the chemical and physical stabilities of electrode/solid‐electrolyte interfaces is crucial for the use of solid electrolytes in all‐solid‐state batteries. Directly probing these interfaces during electrochemical reactions would significantly enrich the mechanistic understanding and inspire potential solutions for their regulation. Herein, the electrochemistry of the lithium/Li7La3Zr2O12‐electrolyte interface is elucidated by probing lithium deposition through the electrolyte in an anode‐free solid‐state battery in real time. Lithium plating is strongly affected by the geometry of the garnet‐type Li7La3Zr2O12 (LLZO) surface, where nonuniform/filamentary growth is triggered particularly at morphological defects. More importantly, lithium‐growth behavior significantly changes when the LLZO surface is modified with an artificial interlayer to produce regulated lithium depositions. It is shown that lithium‐growth kinetics critically depend on the nature of the interlayer species, leading to distinct lithium‐deposition morphologies. Subsequently, the dynamic role of the interlayer in battery operation is discussed as a buffer and seed layer for lithium redistribution and precipitation, respectively, in tailoring lithium deposition. These findings broaden the understanding of the electrochemical lithium‐plating process at the solid‐electrolyte/lithium interface, highlight the importance of exploring various interlayers as a new avenue for regulating the lithium‐metal anode, and also offer insight into the nature of lithium growth in anode‐free solid‐state batteries.

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“…Many approaches have been introduced to reduce the interfacial charge-transfer resistance between garnet-type SE and Li, including the introduction of thin film layers of Au [35], Si [36], Ge [37], Al 2 O 3 [38], and ZnO [39], or eliminating the secondary phases, such as LiOH and Li 2 CO 3 , by polishing the surface of SE and using multiple thermal treatments at specific temperatures before and after contact with Li [40][41][42]. However, a more simplified method to form the interface between garnet-type SE and the Li electrode would be preferable and further study is required of the relationship between the interfacial charge-transfer resistance and stability for Li deposition and dissolution reaction at the interface.…”

Section: Introductionmentioning

confidence: 99%

Formation and Stability of Interface between Garnet-Type Ta-doped Li7La3Zr2O12 Solid Electrolyte and Lithium Metal Electrode

et al. 2018

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Garnet-type Li 7-x La 3 Zr 2-x Ta x O 12 (LLZT) is considered a good candidate for the solid electrolyte in all-solid-state lithium batteries because of its reasonably high conductivity around 10 −3 S cm −1 at room temperature and stability against lithium (Li) metal with the lowest redox potential. In this study, we synthesized LLZT with a tantalum (Ta) content of 0.45 via a conventional solid-state reaction process and constructed a Li/LLZT/Li symmetric cell by attaching Li metal foils on the polished top and bottom surfaces of an LLZT pellet. We investigated the influence of heating temperatures and times on the interfacial charge-transfer resistance between LLZT and the Li metal electrode. In addition, the effect of the interface resistance on the stability for Li deposition and dissolution was examined using a galvanostatic cycling test. The lowest interfacial resistance of 25 Ω cm 2 at room temperature was obtained by heating at 175 • C (5 • C lower than the melting point of Li) for three to five hours. We confirmed that the current density at which the short circuit occurs in the Li/LLZT/Li cell via the propagation of Li dendrite into LLZT increases with decreasing interfacial charge transfer resistance.

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Correlating the interface resistance and surface adhesion of the Li metal-solid electrolyte interface

Cited by 94 publications

References 21 publications

Dopant‐Dependent Stability of Garnet Solid Electrolyte Interfaces with Lithium Metal

Dopant‐Dependent Stability of Garnet Solid Electrolyte Interfaces with Lithium Metal

The Role of Interlayer Chemistry in Li‐Metal Growth through a Garnet‐Type Solid Electrolyte

Formation and Stability of Interface between Garnet-Type Ta-doped Li7La3Zr2O12 Solid Electrolyte and Lithium Metal Electrode

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