Structural, Mechanical, and Dynamical Properties of Amorphous Li2CO3 from Molecular Dynamics Simulations

Ebrahiminia, Mahsa; Hooper, Justin B.; Bedrov, Dmitry

doi:10.3390/cryst8120473

Cited by 15 publications

(19 citation statements)

References 35 publications

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“…Instead, the sizes of pores are 5–10 nm, which are equal to or greater than those of Li 2 CO 3 nanoparticles (∼5 nm) in Figure b. Previous investigations have shown that the crystalline Li 2 CO 3 has a little higher diffusivity and ionic conductivity than the amorphous phase. − Thus, the amorphous Li 2 CO 3 may provide charge-transport channels for the delithiation and charge-transfer process, inducing the preferential decomposition of crystal nanoparticles. These nanopores indicate that the crystalline Li 2 CO 3 nanoparticles are consumed and the amorphous region also contributes to being excavated upon charge.…”

Section: Resultsmentioning

confidence: 86%

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Tan

Zhu

et al. 2020

ACS Sustainable Chem. Eng.

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Li−CO 2 batteries are regarded as promising electrochemical devices to simultaneously capture CO 2 and deliver electric energy. Although efforts are made to exploring reaction routes and developing effective catalysts, the discharge and charge behaviors at different current densities and the intrinsic mechanisms are not reported. Herein, a Li−CO 2 battery with a carbon nanotube electrode is investigated. It is found that with an increase of the current density, the discharge voltage plateau gradually decreases. After the initial charge polarization, the following charge process shows a twostage charge voltage profile where the first stage is sensitive to the applied current density, whereas the second one is not. In addition, the electrode discharged at a lower current density has a higher voltage plateau of the first stage. The characterization results demonstrate that the discharge product is a combination of Li 2 CO 3 and carbon in which crystalline Li 2 CO 3 nanoparticles with the size of ∼5 nm are distributed. Upon charging, rich nanopores with the sizes of 5−10 nm are observed, which may come from the shrinkage of both crystalline and amorphous Li 2 CO 3 . Even at the end of charge, Li 2 CO 3 and carbon remain on the electrode, resulting in the irreversible process. Thus, the first charge stage is proposed to be the decomposition of crystal and amorphous Li 2 CO 3 , whereas the second charge stage with a high voltage is attributed to the blockage of transport channels and the accumulation of side products. Furthermore, for the first charge stage, a low discharge current density leads to small sizes of crystalline Li 2 CO 3 combining with amorphous carbon in the products, increasing the transport resistance and causing a high charge voltage. On the contrary, a high discharge current density results in large sizes of Li 2 CO 3 crystals, improving the overall conductivity and leading to a low charge voltage.

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Section: Resultsmentioning

confidence: 86%

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Tan

Zhu

et al. 2020

ACS Sustainable Chem. Eng.

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“…55 Li 2 CO 3 has much poorer Li conductivity (∼10 −3 mS/cm) at room temperature compared to LLZO. 56 There is a large difference in interfacial resistances of the sample that only contains Li 2 CO 3 after exposure to 500 °C and that of the sample that contains Li 2 CO 3 , La 2 Zr 2 O 7 , and La(Ni,Co)O 3 after exposure to 700 °C. The interfacial resistance found from the former was 2.1 kΩ cm 2 and that from the latter was 102 kΩ cm 2 .…”

Section: Discussionmentioning

confidence: 97%

“…There are perovskite Li conductors such as (Li,La)TiO 3 , but Li conduction requires substantial A-site vacancy fraction . Li 2 CO 3 has much poorer Li conductivity (∼10 –3 mS/cm) at room temperature compared to LLZO …”

Section: Discussionmentioning

confidence: 99%

Thermally Driven Interfacial Degradation between Li₇La₃Zr₂O₁₂ Electrolyte and LiNi_0.6Mn_0.2Co_0.2O₂ Cathode

Kim

Bliem

et al. 2020

Chem. Mater.

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Solid-state batteries offer higher energy density and enhanced safety compared to the present lithium-ion batteries using liquid electrolytes. A challenge to implement them is the high resistances, especially at the solid electrolyte interface with the cathode. Sintering at elevated temperature is needed in order to get good contact between the ceramic solid electrolyte and oxide cathodes and thus to reduce contact resistances. Many solid electrolyte and cathode materials react to form secondary phases. It is necessary to find out which phases arise as a result of interface sintering and evaluate their effect on electrochemical properties. In this work, we assessed the interfacial reactions between LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) and Li 7 La 3 Zr 2 O 12 (LLZO) as a function of temperature in air. We prepared model systems by depositing thin-film NMC622 cathode layers on LLZO pellets. The thin-film cathode approach enabled us to use interface-sensitive techniques such as X-ray absorption spectroscopy in the near-edge as well as the extended regimes and identify the onset of detrimental reactions. We found that the Ni and Co chemical environments change already at moderate temperatures, on-setting from 500 °C and becoming especially prominent at 700 °C. By analyzing spectroscopy results along with X-ray diffraction, we identified Li 2 CO 3 , La 2 Zr 2 O 7 , and La(Ni,Co)O 3 as the secondary phases that formed at 700 °C. The interfacial resistance for Li transfer, measured by electrochemical impedance spectroscopy, increases significantly upon the onset and evolution of the detected interface chemistry. Our findings suggest that limiting the bonding temperature and avoiding CO 2 in the sintering environment can help to remedy the interfacial degradation.

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“…Li 2 CO 3 has limited Li‐ion conductivity (10 −3 mS cm −1 ) at room temperature, much lower compared to that in LLZO. [ 91 ] La 2 Zr 2 O 7 and Ruddelsden‐popper phases are also not Li‐ion conductors. [ 27,92 ] We do not expect carbonated species (La 2 O 2 CO 3 , NiCO 3 , and CoCO 3 ) to have good Li‐ion conductivities since they do not have Li in their lattice nor cation vacancy channel for lithium ion transport.…”

Section: Discussionmentioning

confidence: 99%

Avoiding CO₂ Improves Thermal Stability at the Interface of Li₇La₃Zr₂O₁₂ Electrolyte with Layered Oxide Cathodes

Kim

Waluyo

Hunt

et al. 2022

Advanced Energy Materials

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Solid‐state batteries promise higher energy densities and better safety than Li‐ion batteries with liquid electrolytes. However, the interface between solid electrolyte and cathode is unstable at the elevated temperatures that are needed while sintering to achieve good bonding between ceramic components. Here, the hypothesis is that, the gas environment, especially the presence of CO2, is critical in determining the stability of the solid electrolyte–cathode interface. The effect of gas species on the interface is systematically probed, by a using Li7La3Zr2O12 (LLZO) solid electrolyte with a thin film LiNi0.6Mn0.2Co0.2O2 cathode as a model system to enable interface sensitivity. Detrimental phases formed at the interface and their onset conditions are identified by X‐ray absorption spectroscopy, X‐ray diffraction, and Gibbs free energy analysis. As a result, removing CO2 and minimizing H2O(g) during sintering is necessary to obtain good contact at the LLZO|cathode interface without forming secondary phases. Sintering in O2 is ideal, yielding excellent chemical stability and low interfacial resistance. Secondary phases also do not form in N2, but oxygen loss occurs at elevated temperatures. The interfacial resistance obtained upon sintering in pure O2 is comparable to the lowest values at LLZO interfaces with protective coatings, but here without the need for interface coatings.

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Structural, Mechanical, and Dynamical Properties of Amorphous Li2CO3 from Molecular Dynamics Simulations

Cited by 15 publications

References 35 publications

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Thermally Driven Interfacial Degradation between Li₇La₃Zr₂O₁₂ Electrolyte and LiNi_0.6Mn_0.2Co_0.2O₂ Cathode

Avoiding CO₂ Improves Thermal Stability at the Interface of Li₇La₃Zr₂O₁₂ Electrolyte with Layered Oxide Cathodes

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Structural, Mechanical, and Dynamical Properties of Amorphous Li2CO3 from Molecular Dynamics Simulations

Cited by 15 publications

References 35 publications

Investigation on the Discharge and Charge Behaviors of Li-CO2 Batteries with Carbon Nanotube Electrodes

Investigation on the Discharge and Charge Behaviors of Li-CO2 Batteries with Carbon Nanotube Electrodes

Thermally Driven Interfacial Degradation between Li7La3Zr2O12 Electrolyte and LiNi0.6Mn0.2Co0.2O2 Cathode

Avoiding CO2 Improves Thermal Stability at the Interface of Li7La3Zr2O12 Electrolyte with Layered Oxide Cathodes

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Product

Resources

About

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Investigation on the Discharge and Charge Behaviors of Li-CO₂ Batteries with Carbon Nanotube Electrodes

Thermally Driven Interfacial Degradation between Li₇La₃Zr₂O₁₂ Electrolyte and LiNi_0.6Mn_0.2Co_0.2O₂ Cathode

Avoiding CO₂ Improves Thermal Stability at the Interface of Li₇La₃Zr₂O₁₂ Electrolyte with Layered Oxide Cathodes