X-ray micro-tomography at the Advanced Light Source

MacDowell, Alastair A.; Parkinson, Dilworth; Haboub, A.; Schaible, Eric; Nasiatka, J.; Yee, Conway; Jameson, John R.; Ajo‐Franklin, Jonathan; Brodersen, Craig R.; McElrone, Andrew J.

doi:10.1117/12.930243

Cited by 66 publications

(43 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The capacity evolution for battery A and B are plotted in Figure 5 Figure 5b, was able to hold a C/8 discharge capacity of about 147 mAh/g for 60 cycles before starting to drop down to 143.6 mAh/g at cycle 74. For all of the batteries, the charge and discharge capacity evolution is similar in trend.…”

Section: Resultsmentioning

confidence: 63%

See 1 more Smart Citation

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Devaux

Harry

Parkinson

et al. 2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

Solid block polymer electrolytes are promising candidates for the development of high energy density rechargeable lithium metal based batteries. All solid-state batteries comprising lithium metal negative electrode and lithium iron phosphate (LiFePO 4 ) composite positive electrode were assembled. A polystyrene-b-poly(ethylene oxide) (SEO) copolymer doped with a lithium salt was used as the electrolyte. After cycling the batteries, the reason for capacity fade and failure was determined by imaging the batteries using synchrotron hard X-ray microtomography. These experiments revealed partial delamination of the lithium foil and the block copolymer electrolyte layer. The void volume between the foil and electrolyte layer obtained after 40 to 90 cycles is comparable to volume change in the battery during one cycle. A simple model to account for the effect of delamination on current density in the battery is presented. Capacity fade and battery failures observed in our experiments are consistent with this model. No evidence of lithium dendrite formation was found. In contrast, cycled lithium-lithium symmetric cells with the same polymer electrolyte at the same current density failed due to dendrite formation. No evidence of delamination was found in these cells. Solid polymer electrolytes are promising candidates for the development of high performance rechargeable batteries comprising a lithium (Li) metal electrode due to their chemical stability toward lithium and their mechanical resistance to dendrite growth.1-3 After the pioneering work by Fenton et al., 4 where poly(ethylene oxide) (PEO) laden with alkali metal salts was shown to possess good ionic conductivity, its application as a polymer electrolyte in a full cell was demonstrated by Armand et al. [5][6][7] PEO is a semi-crystalline polymer at room temperature. Ionic transport in PEO electrolytes is linked to segmental motion of the polymer chains, 8,9 and occurs predominantly in the amorphous phase.10 Thus solid polymer electrolyte based batteries must be operated at temperatures (T) above the PEO melting temperature. However, amorphous PEO is too soft to avoid short circuit due to lithium dendrite growth. 11,12 One approach for resolving this problem is the use of a block copolymer electrolyte. [13][14][15][16][17][18][19][20][21][22] Immiscibility between the blocks induces microphase separation, producing hard insulating phases interspersed with soft, ionically conductive phases. [23][24][25] In studies utilizing block copolymers as solid polymer electrolytes, the mechanical phase is usually made of a high glass transition temperature polymer such as polystyrene. [26][27][28][29] Extensive work on the thermodynamics of polystyrene-b-poly(ethylene oxide) (SEO) diblock copolymers [30][31][32][33] indicate that the tendency for microphase separation is enhanced by the presence of ions. 34,35 For symmetric SEO electrolytes, i.e. copolymers wherein the volume fraction of the conducting phase is above 50%, the ionic conductivity has been shown to increase wit...

show abstract

Section: Resultsmentioning

confidence: 63%

“…74 The samples were illuminated using monochromatic hard X-rays of 25 keV energy. The samples were imaged at either room temperature or at 90…”

mentioning

confidence: 99%

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Devaux

Harry

Parkinson

et al. 2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…The measurements were carried out at the Advanced Light Source at the Lawrence Berkeley National Laboratory. Beamline 8.3.2, a hard XR imaging beamline (MacDowell et al, 2012), was chosen for the measurement. The sample, mounted on a wooden stub, was measured in a "local area" configuration -the sample was slightly larger than the field of view (FOV ∼0.83 mm), using a continuous tomography procedure.…”

Section: Sans/usansmentioning

confidence: 99%

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Beckingham

Steefel

Swift

et al. 2017

Geochimica et Cosmochimica Acta

121

View full text Add to dashboard Cite

The rates of mineral dissolution reactions in porous media are difficult to predict, in part because of a lack of understanding of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area used in reactive transport models for porous media are typically ad hoc and often based on average grain size, increased to account for surface roughness or decreased by several orders of magnitude to account for reduced surface reactivity of field as opposed to laboratory samples. In this study, accessible mineral surface areas are determined for a sample from the reservoir formation at the Nagaoka pilot CO2 injection site (Japan) using a multi-scale image analysis based on synchrotron Xray microCT, SEMQEMSCAN, XRD, SANS, and FIB-SEM. This analysis not only accounts for accessibility of mineral surfaces to macro-pores, but also accessibility through connected micro-pores in smectite, the most abundant clay mineral in this sample. While the imaging analysis reveals that most of the micro-and macro-pores are well connected, some pore regions are unconnected and thus inaccessible to fluid flow and diffusion. To evaluate whether mineral accessible surface area accurately reflects reactive surface area a flow-through core experiment is performed and modeled at the continuum scale. The core experiment is performed under conditions replicating the pilot site and the evolution of effluent solutes in the aqueous phase is tracked.Various reactive surface area models are evaluated for their ability to capture the observed effluent chemistry, beginning with parameter values determined as a best fit to a disaggregated sediment experiment (Beckingham et al., 2016) described previously.Simulations that assume that all mineral surfaces are accessible (as in the disaggregated sediment experiment) over-predict the observed mineral reaction rates, suggesting that a reduction of RSA by a factor of 10-20 is required to match the core flood experimental data. While the fit of the effluent chemistry (and inferred mineral dissolution rates) greatly improve when the pore-accessible mineral surface areas are used, it was also necessary to include highly reactive glass phases to match the experimental observations, in agreement with conclusions from the disaggregated sediment experiment. It is hypothesized here that the 10-20 reduction in reactive surface areas based on the limited pore accessibility of reactive phases in core flood experiment may be reasonable for poorly sorted and cemented sediments like those at the Nagaoka site, although this reflects pore rather than larger scale heterogeneity.

show abstract

“…50 The samples were illuminated at room temperature using monochromatic hard X-rays of 25 keV energy. The X-rays radiograms were converted into visible light using a 20 μm thick LuAG scintillator.…”

Section: Methodsmentioning

confidence: 99%

Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

Devaux

Wang

Thelen

et al. 2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

Lithium (Li) batteries comprising multivalent positive active materials such as copper vanadium oxide have high theoretical capacity. These batteries with a conventional liquid electrolyte exhibit limited cycle life because of copper dissolution into the electrolyte. We report here on the characterization of solid-state Li metal batteries with a positive electrode based on α-Cu 6.9 V 6 O 18.9 (α-CuVO 3 ). We replaced the liquid electrolyte by a nanostructured solid block copolymer electrolyte comprising of a mixture of polystyreneb-poly(ethylene oxide) (SEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt. In situ X-ray diffraction was used to follow the Li insertion/de-insertion mechanism into the α-CuVO 3 host material and its reversibility. In situ X-ray scattering revealed that the multistep electrochemical reactions involved are similar in the presence of liquid or solid electrolyte. The capacity fade of the solid-state batteries is less rapid than that of α-CuVO 3 -Li metal batteries with a conventional liquid electrolyte. Hard X-ray microtomography revealed that upon cycling, voids and Cu-rich agglomerates were formed at the interface between the Li metal and the SEO electrolyte. The void volume and the volume occupied by the Cu-rich agglomerates were independent of C-rate and cycle number. There is considerable interest in copper vanadium oxide (CuVO) positive electrodes for rechargeable lithium (Li) batteries. In principle, this material can exhibit high capacity due to multistep electrochemical reactions with Li + ions. In pioneering work, Yamaki and coworkers reported on reversible Li insertion and removal in CuVO compounds.1-3 They showed that a battery comprising a Li metal negative electrode, β-Cu 2 V 2 O 7 positive electrode, and a conventional liquid electrolyte (a mixture of LiClO 4 in propylene carbonate and dimethoxyethane) could be cycled 100 times at 0.5 mA/cm 2 , with an average delivered capacity of 260 mAh/g. The battery failed abruptly due to a short which was attributed to the deposition of Cu metal on the Li electrode. These studies spark considerable interest in CuVO electrodes. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] In a more recent study, Morcrette et al. showed reversible insertion of 6 Li into Cu 2.33 V 4 O 11 through a reversible Cu extrusion-insertion process.18 During the discharge step, the Li + ions enter the host material and the copper ions are pushed to the material edges where they are reduced, forming Cu metal dendrites. During the charge step, Cu metal is oxidized, producing copper ions that re-enter the host material. This original study opened a new class of CuVO materials. 19-21However, for practical applications, battery failure due to dissolution of Cu into the liquid electrolyte and subsequent plating on the Li electrode needs to be addressed.The potential to use poly(ethylene oxide) (PEO) as an electrolyte in Li batteries was demonstrated by Fenton et al. 22 and Armand et al. 23,24 While most of the studies on PEO-based electrolytes emplo...

show abstract

X-ray micro-tomography at the Advanced Light Source

Cited by 66 publications

References 9 publications

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Failure Mode of Lithium Metal Batteries with a Block Copolymer Electrolyte Analyzed by X-Ray Microtomography

Evaluation of accessible mineral surface areas for improved prediction of mineral reaction rates in porous media

Lithium Metal-Copper Vanadium Oxide Battery with a Block Copolymer Electrolyte

Contact Info

Product

Resources

About