scholarly journals Mechanism of Li2S formation and dissolution in Lithium-Sulphur batteries

2021 ◽  
Author(s):  
Christian Prehal ◽  
Sara Drvarič Talian ◽  
Alen Vizintin ◽  
Heinz Amenitsch ◽  
Robert Dominko ◽  
...  
Keyword(s):  
High Performance ◽  
Surface Film ◽  
Rate Capability ◽  
Stochastic Modelling ◽  
Phase Evolution ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Chemical Phase

Abstract Insufficient understanding of the mechanism that reversibly converts sulphur into lithium sulphide (Li2S) via soluble polysulphides (PS) hampers the realization of high performance lithium-sulphur cells. Typically Li2S formation is explained by direct electroreduction of a PS to Li2S; however, this is not consistent with the size of the insulating Li2S deposits. Here, we use in situ small and wide angle X-ray scattering (SAXS/WAXS) to track the growth and dissolution of crystalline and amorphous deposits from atomic to sub-micron scales during charge and discharge. Stochastic modelling based on the SAXS data allows quantification of the chemical phase evolution during discharge and charge. We show that Li2S deposits predominantly via disproportionation of transient, solid Li2S2 to form primary Li2S crystallites and solid Li2S4 particles. We further demonstrate that this process happens in reverse during charge. These findings show that the discharge capacity and rate capability in Li-S battery cathodes are therefore limited by mass transport through the increasingly tortuous network of Li2S / Li2S4 / carbon pores rather than electron transport through a passivating surface film.

scholarly journals In situ small-angle X-ray scattering reveals solution phase discharge of Li–O2 batteries with weakly solvating electrolytes

2021 ◽  
Vol 118 (14) ◽  
pp. e2021893118
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Ludek Lovicar ◽  
Manfred Kriechbaum ◽  
...  
Keyword(s):  
Structural Information ◽  
Surface Film ◽  
Phase Evolution ◽  
Scattering Data ◽  
Carbon Surface ◽  
X Ray ◽  
Surface Areas ◽  
X Ray Scattering ◽  
Ray Scattering

Electrodepositing insulating lithium peroxide (Li2O2) is the key process during discharge of aprotic Li–O2 batteries and determines rate, capacity, and reversibility. Current understanding states that the partition between surface adsorbed and dissolved lithium superoxide governs whether Li2O2 grows as a conformal surface film or larger particles, leading to low or high capacities, respectively. However, better understanding governing factors for Li2O2 packing density and capacity requires structural sensitive in situ metrologies. Here, we establish in situ small- and wide-angle X-ray scattering (SAXS/WAXS) as a suitable method to record the Li2O2 phase evolution with atomic to submicrometer resolution during cycling a custom-built in situ Li–O2 cell. Combined with sophisticated data analysis, SAXS allows retrieving rich quantitative structural information from complex multiphase systems. Surprisingly, we find that features are absent that would point at a Li2O2 surface film formed via two consecutive electron transfers, even in poorly solvating electrolytes thought to be prototypical for surface growth. All scattering data can be modeled by stacks of thin Li2O2 platelets potentially forming large toroidal particles. Li2O2 solution growth is further justified by rotating ring-disk electrode measurements and electron microscopy. Higher discharge overpotentials lead to smaller Li2O2 particles, but there is no transition to an electronically passivating, conformal Li2O2 coating. Hence, mass transport of reactive species rather than electronic transport through a Li2O2 film limits the discharge capacity. Provided that species mobilities and carbon surface areas are high, this allows for high discharge capacities even in weakly solvating electrolytes. The currently accepted Li–O2 reaction mechanism ought to be reconsidered.

scholarly journals In situ small angle X-ray scattering reveals solution phase discharge of Li-O2 batteries with weakly solvating electrolytes

2020 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Structural Information ◽  
Surface Film ◽  
Phase Evolution ◽  
Scattering Data ◽  
Carbon Surface ◽  
X Ray ◽  
Surface Areas ◽  
X Ray Scattering ◽  
Ray Scattering

Electrodepositing insulating and insoluble Li2O2 is the key process during discharge of aprotic Li-O2 batteries and determines rate, capacity, and reversibility. Current understanding states that the partition between surface adsorbed and dissolved LiO2 governs whether Li2O2 grows as a conformal surface film or larger particles, leading to low or high capacities, respectively. However, governing factors for Li2O2 packing density and capacity need better understanding, requiring in situ metrologies with structural sensitivity from the atomic to sub-micron scale. Here, we establish in situ small and wide angle X-ray scattering as a suitable method to record the Li2O2 phase evolution with atomic to sub-micrometer resolution during cycling a custom-built in situ Li-O2 cell. Combined with sophisticated data analysis, SAXS allows retrieving rich quantitative structural information from complex multi-phase systems. Surprisingly, we find that features are absent that would point at a Li2O2 surface film formed via two consecutive electron transfers, even in poorly solvating electrolytes thought to be prototypical for surface growth. All scattering data can be modeled by stacks of thin Li2O2 platelets eventually forming large toroidal particles. Higher discharge overpotentials (high currents) lead to smaller Li2O2 particles, but there is no transition to an electronically passivating, conformal Li2O2 coating. This implies that mass transport of reactive species rather than electronic transport through a Li2O2 film limits the discharge capacity. Provided that species mobilities and carbon surface areas are high, this allows for high discharge capacities even in poorly solvating electrolytes. The currently accepted Li-O2 reaction mechanism ought to be reconsidered.<br>

scholarly journals In situ small angle X-ray scattering reveals solution phase discharge of Li-O2 batteries with weakly solvating electrolytes

2020 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Structural Information ◽  
Surface Film ◽  
Phase Evolution ◽  
Scattering Data ◽  
Carbon Surface ◽  
X Ray ◽  
Surface Areas ◽  
X Ray Scattering ◽  
Ray Scattering

Electrodepositing insulating and insoluble Li2O2 is the key process during discharge of aprotic Li-O2 batteries and determines rate, capacity, and reversibility. Current understanding states that the partition between surface adsorbed and dissolved LiO2 governs whether Li2O2 grows as a conformal surface film or larger particles, leading to low or high capacities, respectively. However, governing factors for Li2O2 packing density and capacity need better understanding, requiring in situ metrologies with structural sensitivity from the atomic to sub-micron scale. Here, we establish in situ small and wide angle X-ray scattering as a suitable method to record the Li2O2 phase evolution with atomic to sub-micrometer resolution during cycling a custom-built in situ Li-O2 cell. Combined with sophisticated data analysis, SAXS allows retrieving rich quantitative structural information from complex multi-phase systems. Surprisingly, we find that features are absent that would point at a Li2O2 surface film formed via two consecutive electron transfers, even in poorly solvating electrolytes thought to be prototypical for surface growth. All scattering data can be modeled by stacks of thin Li2O2 platelets eventually forming large toroidal particles. Higher discharge overpotentials (high currents) lead to smaller Li2O2 particles, but there is no transition to an electronically passivating, conformal Li2O2 coating. This implies that mass transport of reactive species rather than electronic transport through a Li2O2 film limits the discharge capacity. Provided that species mobilities and carbon surface areas are high, this allows for high discharge capacities even in poorly solvating electrolytes. The currently accepted Li-O2 reaction mechanism ought to be reconsidered.<br>

In-Situ Synchrotron X-ray Scattering Studies of the Thermally-Induced Self-Assembly of High-Performance Aromatic Copolyesters

2014 ◽  
Vol 6 (11) ◽  
pp. 2352-2357
Author(s):  
Young Yong Kim ◽  
Kyuyoung Heo ◽  
Kyeong Sik Jin ◽  
Jehan Kim ◽  
Jong Ryang Kim ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Thermally Induced ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals DATASW, a tool for HPLC–SAXS data analysis

2015 ◽  
Vol 71 (6) ◽  
pp. 1347-1350 ◽  
Author(s):  
Alexander V. Shkumatov ◽  
Sergei V. Strelkov
Keyword(s):  
High Performance ◽  
Model Building ◽  
Sliding Window ◽  
Data Interpretation ◽  
Resolution Method ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Heterogeneous Samples ◽  
Folding State

Small-angle X-ray scattering (SAXS) in solution is a common low-resolution method which can efficiently complement the high-resolution information obtained by crystallography or NMR. Sample monodispersity is key to reliable SAXS data interpretation and model building. Beamline setups with inline high-performance liquid chromatography (HPLC) are particularly useful for accurate profiling of heterogeneous samples. The programDATASWperforms averaging of individual data frames from HPLC–SAXS experiments using a sliding window of a user-specified size, calculates overall parameters [I(0),Rg,Dmaxand molecular weight] and predicts the folding state (folded/unfolded) of the sample. Applications ofDATASWare illustrated for several proteins with various oligomerization behaviours recorded on different beamlines.DATASWbinaries for major operating systems can be downloaded from http://datasw.sourceforge.net/.

Exploring the rate dependence of phase evolution in P2-type Na2/3Mn0.8Fe0.1Ti0.1O2

2019 ◽  
Vol 7 (19) ◽  
pp. 12115-12125 ◽  
Author(s):  
Damian Goonetilleke ◽  
Sunny Wang ◽  
Elena Gonzalo ◽  
Montserrat Galcerán ◽  
Damien Saurel ◽  
...  
Keyword(s):  
Electrode Material ◽  
High Performance ◽  
Structural Evolution ◽  
Phase Evolution ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
X Ray Diffraction ◽  
X Ray

P2-type Na2/3Mn0.8Fe0.1Ti0.1O2, a promising high-performance electrode material for use in ambient temperature sodium-ion batteries, is examined using operando and long-term in situ synchrotron X-ray diffraction studies to reveal the structural evolution during battery function.

scholarly journals High rate hybrid MnO2@CNT fabric anodes for Li-ion batteries: properties and a lithium storage mechanism study by in situ synchrotron X-ray scattering

2019 ◽  
Vol 7 (46) ◽  
pp. 26596-26606 ◽  
Author(s):  
Moumita Rana ◽  
Venkata Sai Avvaru ◽  
Nicola Boaretto ◽  
Víctor A. de la Peña O'Shea ◽  
Rebeca Marcilla ◽  
...  
Keyword(s):  
High Performance ◽  
High Rate ◽  
Li Ion Batteries ◽  
Mechanism Study ◽  
Lithium Storage ◽  
X Ray ◽  
Storage Mechanism ◽  
X Ray Scattering ◽  
Li Ion

Unravelling lithium storage mechanism in high performance MnO2@CNT Li-ion battery anode by in situ X-ray synchrotron scattering.

A Revised O2 Reduction Model in Li-O2 Batteries as Revealed by in Situ Small Angle X-Ray Scattering

2019 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Small Angle ◽  
Wide Angle ◽  
Reduction Mechanism ◽  
Reduction Model ◽  
X Ray ◽  
X Ray Scattering ◽  
O2 Reduction ◽  
Ray Scattering

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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