bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of Micro Optical Ring Electrodes for Scanning Photoelectrochemical Microscopy Applications
Authors: Thomas Nikita , Ahmed Nafisa , Trinh Dao , Kuss Sabine
Published: July 2022

Micro-Optical-Ring electrodes (MOREs) have shown their usefulness in nonbiological applications in the past, but their application to biological samples for diagnostic purposes has yet to be explored. Herein, a simple and cost effective fabrication method of MOREs with a defined geometry is presented. These microelectrodes were characterized by electrochemistry, numerical modeling and Scanning Electron Microscopy (SEM). The integration of MOREs into scanning probe techniques, such as Scanning Electrochemical/Photoelectrochemical Microscopy (SECM/SPECM) enables the sensitive detection and quantification of cell metabolites at the micro- and nanoscopic level. The applicability of the fabricated MOREs was tested by monitoring oxygen production in the biological model systems of Chlorella kessleri and Eremosphaera viridis. A variation in oxygen production levels by the algae was observed in the presence and absence of light, emitted through the MORE-integrated optical fiber. This proof-of-concept study demonstrates the applicability of MOREs to biological systems.
Advanced Lithium-Ion Capacitors Based on Pre-Lithiated Si/SiOx Negative Electrode
Authors: Kim Nam Gyu , Chung Dong Jae , Park Min-Sik , Kim Hansu
Published: July 2022

Lithium-ion capacitor (LIC) was developed to increase the energy density of conventional electrochemical double-layer capacitors. However, the inherent relatively low theoretical capacity and sluggish interfacial kinetics of conventionally used graphite anode in LIC should be overcome. In this work, we investigated pre-lithiated carbon coated Si/SiOx negative electrode and activated carbon positive electrode to develop high performance LIC. Si/SiOx nanoparticles were prepared by simple sol-gel reaction, followed by carbon coating and pre-lithiation process. LIC with pre-lithiated carbon coated Si/SiOx negative electrode showed improved rate capability and cycle performance at a current density of 850 mA g-1 lasting for up to 1000 cycles compared to LIC with the conventional graphite anode. These results show that pre-lithiated carbon coated Si/SiOx negative electrode is superior to the conventional graphite negative electrode. In this presentation, the pre-lithiation conditions and electrochemical properties of carbon coated Si/SiOx anode in LIC will be discussed more in detail.
(Digital Presentation) Stable Passivation Layer of Oxygen Deficient α-MoO3-X Nanobelts Suppress Li Dendrites to Achieve High-Capacity Li-S Battery
Authors: Paste Rohan , Abbas Syed Ali , Singh Anupriya , Lin Hong-Cheu , Chu Chih Wei
Published: July 2022

The high energy density lithium metal batteries (LMBs) are considered promising energy storage devices for future development. The Li metal reacts with electrolyte and forms an unstable solid electrolyte interphase (SEI), such SEI break down upon cycles and exposes fresh Li metal to the electrolyte which further initiate the growth of Li dendrites. The Li dendrites eventually penetrate the separator and can cause catastrophic battery failure. To suppress the growth of Li dendrites, we have formed a passivation layer on Li metal anode by using oxygen-deficient α-MoO3 nanobelts (MNBs) via a simple spray coating method. The MNBs were synthesized by simple ball milling method. The porous net-like interconnected structure formed by MNBs accommodates the excess Li, provides shorter diffusion pathways to Li+ ions and avoids the dendritic growth and pulverization of SEI. The Li-Li symmetrical cells with MNBs coated Li electrodes (MNB-Li) operated at current density of 1 mA cm–2 with a deposition capacity of 1 mAh cm–2 shows lower overpotential (~30 mV) than the cells with pristine Li (~45mV) after 100 hours of cycling. Oxygen vacancies present on the surface of MNBs act as shallow donors and boost carrier concentration, resulting in increased surface conductivity. The MNB-Li paired up with sulfur expanded graphite (SEG) cathode and activated expanded graphite (AEG) coated separator offers ~1077 mAh g-1 initial capacity at 0.5C (1C=1600 mAh g-1) and ~99 % coulombic efficiency for 100 cycles.

Figure 1
(Invited, Digital Presentation) Tafel Analysis Algorithm: Objective Identification of the Linear Region
Authors: Leddy Johna , Coduto Joshua Richard
Published: July 2022

Electrocatalysts for hydrogen evolution and oxidation (HER and HOR) reactions, oxygen reduction and evolution (ORR and OER) reactions, and carbon dioxide reduction reactions (CO2RR) are evaluated by Tafel analysis. The Tafel equation specifies the log-linear relationship between current and overpotential 𝛈. Heterogenous electron transfer parameters of exchange current density j
o and transfer coefficient 𝛂 are found. Standard heterogenous electron transfer rate k
0 can be found from j
o.

Conventionally, Tafel analysis is an extension of the Butler-Volmer equation applied at high overpotentials but where mass transport is not significant and the reverse reaction rate is negligible. Applicable at high 𝛈 when electron transfer rates are slow, kinetic parameters are extracted by linear regression. The conventional method is, however, subject to inaccuracies because the linear region is often determined subjectively, without attention to the constraints on overpotential range, no mass transport limitations, and low j
o.

An algorithm is developed to automate Tafel analysis with the objective to increase measurement accuracy and decrease subjective identification of the linear region. From linear sweep voltammograms (LSVs), j
o and α are determined from Tafel slopes in the best fit, linear range.

Comparisons of kinetic parameters between conventional and algorithmic Tafel analyses are made for the hydrogen evolution reaction (HER, 2H+ + 2e- ⇌ H2) on various unmodified electrodes and electrodes modified with Nafion® composites. The algorithmic Tafel analysis parameters correlate well with conventional Tafel analyses that respect constraints on mass transport, 𝛈, and j
o. Similar agreement is observed between literature and algorithmically fitted kinetic parameters for different electrochemical systems. The algorithm allows for straightforward, rapid Tafel analysis for improved measurement of rate parameters that is independent of user bias in selection of the linear region.

Acknowledgments

This work was supported by the Army Research Office.
(Invited) Towards a FRET Based DNA SAM Biosensor for Detection of Nucleic Acids
Authors: Grzedowski Adrian , Bizzotto Dan
Published: July 2022

Rapid and sensitive detection of nucleic acids is an essential tool in many medical and clinical settings, that allows for fast diagnosis of bacterial and viral infections. Here, we present a DNA FRET-based biosensor to detect a hybridization event on a DNA SAM on gold surface. The monolayer was prepared by a potential assisted thiol exchange deposition, which provides better control over the surface coverage and its uniformity1. Our approach relies on a change in FRET (Förster Resonance Energy Transfer) signal caused by variations in distance between fluorophores. FRET imaging is a well-known, very sensitive technique, used commonly in many areas of chemistry and microbiology. FRET signal depends strongly on the distance between an acceptor and a donor fluorophore. It is an excellent tool to analyze small changes in DNA distance between adjacent strands and the surface2. Metal quenching also plays a major role, since fluorescence is strongly dependent on the distance from the metal surface3, which is an efficient quencher. Fluorophores, both acceptor and donor, are quenched significantly by the gold surface, this however, decreases substantially as the distance increases between the surface and fluorophore. As DNA is binding its complementary strands, the distance between the surface and the fluorophore labelled end increases.

Using a self-assembly property of thiols on gold surface, we show that mixed ssDNA SAM composed of two strands of thiolated ssDNA, each labelled with a different FRET fluorophore, gives an 8-to-10-fold signal enhancement, upon DNA hybridization (see figure 1). Binding of a complementary strand rigidifies the adsorbed DNA structure, and as a result we observe the increase in signal due to weaker gold quenching and shorter distance between FRET participating fluorophores. Moreover, by utilizing a single crystal electrode, we can study different surface concentration regimes and fluorescence signal increases, based on surface crystallography and the electrode potential.

(1) Leung, K. K.; Gaxiola, A. D.; Yu, H.-Z.; Bizzotto, D. Tailoring the DNA SAM Surface Density on Different Surface Crystallographic Features Using Potential Assisted Thiol Exchange. Electrochim. Acta
2018, 261, 188–197. https://doi.org/https://doi.org/10.1016/j.electacta.2017.12.114.

(2) Verhaven, A.; Doneux, T.; Bizzotto, D. Application of FRET Microscopy to the Study of the Local Environment and Dynamics of DNA SAMs on Au Electrodes. Langmuir
2018, 34 (49), 14802–14810. https://doi.org/10.1021/acs.langmuir.8b02131.

(3) Casanova-Moreno, J.; Yu, Z. L.; Massey-Allard, J.; Ditchburn, B.; Young, J. F.; Bizzotto, D. Luminescence in Electrochemistry; Springer International Publishing: Cham, 2017; pp 21– 77.

Figure 1
Electro-Catalytic Reduction of Nitrogen to Ammonia By Vanadium Oxide and Vanadium Oxynitride Thin Films: The Roles of Metal Oxophilicity, and Lattice Oxygen and Nitrogen Towards NRR
Authors: D'Souza Francis , Ganesan Ashwin , Osonkie Adaeze , Chukwunenye Precious , Rashed Ishika , Anwar Fatima , Gharee Mojgan , Balogun Kabirat , Cundari Thomas R. , Kelber Jeffry
Published: July 2022

Electro-catalytic reduction of N2 to NH3 using Earth-abundant oxide and oxynitrides is an energy- and environmentally-friendly alternative to the Haber-Bosch process. The present contribution summarizes our recent progress on vanadium oxide (VO) and vanadium oxynitride (VON) thin films1,2 as electrochemical nitrogen reduction reaction (NRR) catalysts at neutral pH conditions. In the case of VO films, the N-free VIII/IV-oxide, created by O2 plasma oxidation of polycrystalline vanadium, exhibited N2 reduction at an onset potential of -0.16 V vs. Ag/AgCl. DFT calculations indicated that N2 scission from O-supported V-centers is energetically favorable by ~18 kcal/mole as compared to N-supported sites. Interestingly, in the case of VON catalysts, both electrochemistry and photoemission data revealed the involvement of both lattice N and dissolved N2 in the NRR process. Our results also show that NH3 production from VON lattice N occurs in the presence or absence of N2 and involves the formation of V≡N: intermediates or similar unsaturated VN surface states. This is in contrast to VO where N2 reduction occurred in the presence or absence of lattice N, and without N incorporation into a vanadium oxide lattice. Thus, both lattice N and N2 reduction mechanisms involve oxide-supported V surface sites ([V]O) in preference to N-supported sites ([V]N). DFT calculations revealed the formation of V≡N:, V-N=N-H, plus other plausible reaction intermediates that are energetically favored at [V]O rather than at [V]N surface sites.

Acknowledgment: This work was supported by the National Science Foundation through grants DMR-2112864 (to JAK, TRC, and FD) and partial support by CHE-1953547 (to TRC). Additional NSF support for the UNT CASCaM HPC cluster via Grant CHE-1531468 is also gratefully acknowledged.

Ganesan, A. Osonkie, P. Chukwunenye, T. Cundari, F. D'Souza, J. Kelber. Electrochemical Reduction of N2 to ammonia by vanadium oxide thin films at neutral pH, J. Electrochem. Soc., 2021, 168, 026504.

Osonkie, A. Ganesan, P. Chukwunenye, F. Anwar, K. Balogun, M. Gharee, I. Rashed, T. R. Cundari, F. D’Souza, and J. A. Kelber, Electro-catalytic reduction of nitrogen to ammonia: The roles of lattice O and N in reduction at vanadium oxynitride surfaces, ACS Adv. Mater & Interface, 2021, in revision.
Highly Efficient Multi-Atom Pt and PtRu Catalysts for Anion Exchange Membrane Fuel Cells
Authors: Adabi Firouzjaie Horie , Shakouri Abolfazl , Williams Christopher , Regalbuto John R , Mustain William Earl
Published: July 2022

During the last decade, anion exchange membrane fuel cells (AEMFCs) have gained popularity due to their

promise to provide low cost, high efficiency, high power density, and zero-emissions. Recent years have seen

a significant increase in the achievable peak power density and lifetime of AEMFCs, though that performance

has come with high loadings of Pt and PtRu catalysts at the cathode and anode, respectively1,2

. However, to displace incumbent proton exchange membrane fuel cells (PEMFCs), AEMFCs must be able to offer much

lower cost3,4. Therefore, the U.S. Department of Energy (DOE) recently set some challenging activity targets

for AEMFCs5; including a near-term target platinum group metal (PGM) loading of 0.2 mg/cm2 by 2023, 0.125

mg/cm2 by 2024 and zero PGM by 2030.

Recently, various efforts have sought to reduce the PGM loading in operating AEMFCs. Some efforts have

focused on developing completely PGM-free catalysts, such as Fe-N-C at the cathode6

. However, the nearterm DOE targets can be met by reducing the loading of existing catalysts, which can be accomplished by

maximizing metal utilization7. One effective strategy is to improve the mass activity of Pt by increasing the

number of active sites through catalyst size or structure control or improving the intrinsic activity of Pt through

the manipulation of its electronic structure. One approach that can be used to reduce the PGM loading is to

create atomically-dispersed catalysts. This can include single atoms or small multi-atom clusters 8,9

.

Therefore, in this work, Pt/C, Pt/NC, PtRu/C and PtRu/NC were fabricated using a simple, and scalable Switch

Solvent Synthesis (SWISS) method. This method synthesizes a high density of multi-atom catalysts. It is able

to do so by limiting the amount of water that is hydrating the synthesis precursors, which allows for

agglomeration to be limited. The catalysts were physically characterized using a wide array of techniques

including x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy

(TEM), and high-resolution Cs aberration-corrected scanning transmission electron microscopy (STEM). The

catalysts were also tested for their oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR)

activity in a rotating disk electrode setup. Their in-situ behavior was also investigated operating AEMFCs.

With this new generation of low-PGM materials, it was possible to reduce the PGM loading by factor of 12

while achieving comparable performance to commercial catalysts. Also, to assemble a cell with ultralow PGM

loading, our previously developed Fe–N–C cathodes6 were paired with a low-loading PtRu/NC anodes (0.05

mg PtRu per cm2, 0.08 mg Pt per cm2), which allowed for the demonstration of a specific power of 25 W per mg PGM (40 W per mg Pt).
Discrete Modeling of Ionic Space Charge Zones in Solids
Authors: Xiao Chuanlian , Chen Chia-Chin , Maier Joachim
Published: July 2022

In this contribution discrete modeling of space charge zones in solids is presented, which is a sensible approach for handling pronounced space charge potentials as well as non-idealities in realistic solid state system1. At interfaces in charge-carrier containing systems, individual charge carriers redistribute, which leads to transport but also storage anomalies2. Such space charge zones are usually described by a continuum picture based on classic Gouy-Chapman (or Mott-Schottky) models. In addition to issues of internal consistency, this continuum approach is questionable if extremely steep profiles close to the interface occur, and analytical corrections are not very helpful. We show how discretization remedies a variety of such short-comings, allows for a straightforward taking account of non-idealities, and even provides surprising insight into double layer capacitance and conductance effects. Combining discrete modeling with the continuum description provides a particularly powerful method with the help of which non-idealities in the first layers (variation in structure, elastic effects, saturation effects, changes in dielectric constant) can be directly addressed. Various examples of practical value for functional ceramics and batteries are discussed. We believe that such discretization represents a substantial progress in the field of space charge theory being advantageous over introducing corrections into the already overstrained Gouy-Chapman function.

References

C. Xiao; C.-C. Chen; J. Maier, Discrete modeling of ionic space charge zones in solids, submitted.

C.-C. Chen, J. Maier, Decoupling electron and ion storage and the path from interfacial storage to artificial electrodes, Nature Energy
2018,
3 (2), 102-108.
Critical Percolation Threshold for Solvation Site Connectivity in Polymer Electrolytes Mixtures
Authors: Sharon Daniel , Deng Chuting , Bennington Peter , Webb Michael , Patel Shrayesh N. , de Pablo Juan , Nealey Paul F.
Published: July 2022

To address the tradeoff between mechanical strength and Li+ conductivity in Poly(Ethylene Oxide) (PEO)-based electrolytes, a rigid nonconductive polymer is frequently added to the electrolyte via blending or copolymerization. The ionic conductivity of mixed PEO electrolytes is generally lower than that of unmixed PEO electrolytes. The suppressed ionic conductivity is attributed to the reduced segmental mobility and connectivity of the conductive PEO cites. Most experimental systems make it difficult to decouple the two mechanisms and accurately examine their impact on conductivity. We compare two symmetric polymer mixtures (50:50 wt%): a miscible polymer blend PEO/PMMA and a disordered block copolymer (BCP) PEO-b-PMMA, both with the same amount of Li salt. Because their chemical and physical properties are the same, changes in ionic conductivity can be attributed solely to local changes in PEO network connectivity. We discover that the mixtures' immediate Li+ solvation sites (<5 Å) are identical to those of unmixed PEO electrolytes. The presence of non-conducting PMMA near the PEO, on the other hand, causes local concentration changes at longer range scales. The BCP is more mixed than the blend electrolyte at these length scales, resulting in a factor of two drop in conductivity. To that end, we propose a quantitative computational model that considers Li+ transport within and across PEO clusters at the appropriate length scales. This new understanding of network connectivity in polymer electrolyte mixtures is critical for the design of future multiphase polymer electrolyte systems.
Understanding the Reversible Electrodeposition of Al in Low-Cost Room Temperature Molten Salts
Authors: Garcia-Mendez Regina , Zheng Jingxu , Archer Lynden A.
Published: July 2022

Al-based batteries are considered an attractive alternative to Li metal batteries due to the use of Al metal as an anode with lower cost, lower reactivity and larger abundance compared to Li. Despite the aforementioned attributes, few electrolytes permit reversible electrodeposition of Al metal at room temperature. Thus, for the last 30 years, expensive imidazolium-based ionic liquids have dominated the field. Even though extensive research has been conducted on imidazolium-based ionic liquids, a systematic study that sheds light on the structural requirements, physicochemical and transport properties required to enable high reversibility has not been conducted. Here, we investigated two ammonium-based systems that show comparable reversibility to imidazolium-based ionic liquids with Coulombic efficiencies up to 99.1% for over 1000 cycles (1 mAh/cm2, 4 mA/cm2). We reveal that high reversibility in ammonium- and imidazolium- based electrolytes is achieved when a critical ratio of the solvation species (AlCl4
- and Al2Cl7
-) is obtained, where Lewis’s acidity and beneficial interfacial reactions continuously etch the Al2O3 resistive interfacial layer and uniform current distribution is attained on the anode. Insights were obtained via construction of phase diagrams, 27Al quantitative NMR, structural considerations, chemical analyses, transport properties and electrochemical measurements. The findings yield quantitative molecular-level understanding of Al electrodeposition in room-temperature ammonium-based molten salts that are up to five times cheaper than the commonly used imidazolium-based electrolytes. The fundamental understanding gained on the structural, physicochemical and transport properties that enable high reversibility of Al electrodeposition in electrolytes can guide engineering approaches for other electrolyte systems for Al-based batteries. Furthermore, the development of low-cost, high-rate capability and long-term stability electrolytes can accelerate the development of high-capacity cathodes leading to higher energy densities relevant for electric vehicles.
(Digital Presentation) On the Nature of Surfactant Adsorption on Metals: Adsorption of Hexylamine on Platinum
Authors: Ostapenko Gennady I. , Kalashnikova Nina A.
Published: July 2022

The kinetics of the Fe2+ and Fe3+ oxidation-reduction reaction on a platinum electrode in 1 M HClO4 was investigated by the EIS method in the presence of hexylamine as a surfactant. With surfactant adsorption, the effective area of the solution-electrode interface decreases. A proportional increase in charge transfer resistance takes place. This resistance values obtained at various hexylamine concentrations. The surface coverage θ(R) for the solution-platinum interface have been calculated.

The hexylamine adsorption at the solution-air interface was investigated by the maximum bubble pressure method. The surface tension γ at various hexylamine concentrations are obtained. The surface coverage θ(γ) for the solution-air interface has been calculated. The area occupied by the hexylamine molecule at the interface and the adsorption layer thickness are estimated.

It is shown that adsorption process is described by the Dhar-Flory-Huggins isotherm at both interfaces. The slope tg α of the θ(R) and θ(γ) dependence on the hexylamine concentration is close to the theoretical unit in the Dhar-Flory-Huggins coordinates. The main parameters of the hexylamine adsorption (adsorption constant Kad, free adsorption energy ΔGad) were calculated for both interfaces (see Table).

Solution-platinum interface

Solution-air interface

tg α

0.94±0.09

0.98±0.18

K
ad / L mol-1

10.0±4.0

15.8±0.3

ΔG
ad / kJ mol-1

–(14.8 ± 5.0)

–(16.7±0.3)

In the general case, the surfactant adsorption on a metal electrode can be due to the interaction of surfactant molecules with the metal or the hydrophobic effect of the surfactant displacement molecules onto the solution surface by polar water molecules. For the solution-air interface, the hydrophobic effect is the main reason for surfactant adsorption at this interface. The values of the main adsorption characteristics on both interfaces are close. Probably, the hydrophobic effect is also the predominant reason for the hexylamine adsorption on platinum. This assumption requires additional studies of the surfactant adsorption on other metals.
Impedance-Based Li-Ion Battery Forecasting amid Uneven Usage
Authors: Jones Penelope , Stimming Ulrich , Lee Alpha
Published: July 2022

Accurate forecasting of Li-ion battery performance is important for easing consumer concerns about the safety and reliability of electric vehicles. Most research on battery health prognostics focuses on the R&D setting where cells are subjected to the same usage patterns, yet in practice there is great variability in use across cells and cycles, making forecasting much more challenging.

In my talk, I will show that a combination of battery `biomarkers’ derived from electrochemical impedance signals with probabilistic machine learning enables us to accurately forecast future battery performance amid uneven usage, even when cell history is completely unknown. More broadly, our results bring into question the concept of a scalar State of Health, and instead suggest that battery state is better quantified by a multidimensional vector. I will discuss how this insight lays the foundations for novel algorithms for battery prognostics and control. I will further outline our application of such algorithms in optimal protocol design for intelligent battery charging, and low-data inference via transfer learning across cell chemistries and usage patterns.
Mns@N/S-C Anode Electrode with High Lithium Storage Property By Simple Polyol Refluxing Method
Authors: Song Moonsu , Hwang Jang-Yeon , Kim Jaekook
Published: July 2022

Transition-metal sulfides are of significant interest as rechargeable battery anodes owing to their low cost, wide availability, eco-friendliness, and high theoretical capacities. However, the structural change due to the volume change during the electrochemical reaction and the capacity decrease due to the dissolution of polysulfide remain as problems. Herein, a simple one-pot polyol refluxing method is used for fabricating a manganese sulfide (MnS) electrode composited with nitrogen and sulfur co-doped carbon (MnS@NS-C) for high-power lithium-ion batteries. This composite electrode is a carbon-coated nanostructure, exhibits unique spherical particle morphology with optimized average partical size (300 < x < 500nm) and porous features. Owing to its nanostructure, porous nature, and an electrically conducting carbon coating network co-doped with heteroatoms, the composite electrode overcomes the strong structural variations and polysulfide dissolution to afford high practical storage capacities, long-term cycle stability, and outstanding rate capability. The MnS@NS-C electrode demonstrated high reversible lithium storage capacities of 999 mAh g-1 at 0.1 A g-1, the highest reversible capacity of 761 mAh g-1 at 2 A g-1 for over 300 cycles, and average rate capacities of 453 mAh g-1 at 10 A g-1. In-situ X-ray diffraction investigations indicated a uniquely combined intercalation-cum-conversion reaction mechanism leading to β-Li2(1-x)MnS, Li2S, and Mn discharge products. The results of this study can provide deep insights into understanding reaction mechanism and motivate further study of transition-metal sulfides for prospective high-energy battery applications.

References

N. Nitta, F. Wu, J. T. Lee and G. Yushin, Mater. Today, 2015, 18, 252–264.

V. Etacheri, R. Marom, R. Elazari, G. Salitra and D. Aurbach, Energy Environ. Sci., 2011, 4, 3243–3262.

Y. Hao, C. Chen, X. Yang, G. Xiao, B. Zou, J. Yang and C. Wang, J. Power Sources, 2017, 338, 9–16.

Y. Ye, C. Jo, I. Jeong and J. Lee, Nanoscale, 2013, 5, 4584–4605.

L. Zhang, L. Zhou, H. Bin Wu, R. Xu and X. W. Lou, Angew. Chemie - Int. Ed., 2012, 51, 7267–7270.
Dehydrogenation-Driven Prelithiation in the Absence of Li Metal to Enhance the Initial Efficiency of Sio-Based Anode Materials in Lithium-Ion Batteries
Authors: Kim Seung Tae , Chung Dong Jae , Youn Donghan , Kim Soohwan , Ma Donghyeok , Lee Jiwhan , Jeong Won Joon , Lee Ji Yeong , Kim Hansu
Published: July 2022

Silicon monoxide (SiO) based materials are long-established high-capacity anode materials that are used in commercialized lithium-ion batteries. However, the inherently low initial Coulombic efficiency (ICE) is a hurdle to overcome, prior to their full potential utilization as anode materials for lithium-ion batteries. In this presentation, we demonstrate that the ICE of SiO can be enhanced to reach up to 90.5%, through a dehydrogenation-driven Li metal absent prelithiation method using lithium hydride (LiH). Released lithium that originates from LiH, preemptively forms lithium silicate phases, the main reason behind the low ICE of SiO. Through laser-assisted atom probe tomography (LA-APT) and scanning transmission electron microscopy (STEM), the formation of three-dimensionally networked Si/lithium silicate nanocomposite was visualized. The prelithiated SiO exhibits a capacity of 1203 mAh g-1 with an ICE of 90.5% without detrimental alterations in electrochemical performance. The boost in ICE of prelithiated SiO results in a 50% enhancement of energy density of the full cell (37 mAh) compared to pristine SiO, with excellent cycle performance lasting for 800 cycles. Further description of the reaction mechanism and the resulting microstructure obtained through the suggested prelithiation will be discussed more in detail in the presentation.
Na Plating and Stripping Using Highly Na-Ion Conductive Solid Polymer Electrolytes Based on Polyvinylidene Fluoride and Polyvinylpyrrolidone
Authors: Bristi Afshana Afroj , Samson Alfred , Thangadurai Venkataraman
Published: July 2022

Solid-state sodium-ion batteries (ss-SIBs) are a promising alternative to commercially available lithium-ion batteries (LIBs) for next-generation energy storage applications. They have lower production costs and are safer than LIBs. Moreover, sodium is more abundant than lithium. The incorporation of solid polymer electrolytes (SPEs) into SIBs has been attracting much more attention due to the easy processability, low costs, safe usability, modification scope, and abundance of polymers. However, SPEs for ss-SIBs with high ionic conductivity and low interfacial resistance between electrolytes and electrodes are lacking. In addition, SPEs face major challenges such as suitable manufacturing methods and the lack of knowledge about low-cost ss-SIBs assembly. Herein, using a facile solution casting process, we have successfully fabricated a high sodium-ion conductive composite SPE film based on polyvinylidene fluoride (PVDF) polymer, polyvinylpyrrolidone (PVP) binder, and NaPF6 salt. A comprehensive characterization has been conducted using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Thermogravimetric Analysis (TGA), Raman, and electrochemical impedance spectroscopy techniques to investigate the structural, thermal, and electrochemical performance of the as-prepared SPE films. High ionic conductivity (8.51 x 10-4 S cm-1 and 8.36 x 10-3 S cm-1 at 23°C and 78 °C, respectively) was observed from the SPE. A hybrid symmetric half-cell assembly (Na foil + 20 µL of 1 M NaClO4 in ethylene carbonate (EC) and propylene carbonate (PC) (EC: PC = 1:1) + Carbon-cloth |SPE| Carbon-cloth + 20 µL of 1 M NaClO4 in EC and PC (EC: PC = 1:1) | Na foil) showed excellent Na plating-stripping performance up to 8 mA cm-2 for 100 cycles. In addition, Na+ transfer mechanism in the composite electrolyte has been investigated using impedance and dielectric spectroscopy. The results indicate the promising applicability of SPEs in next-generation high-power rechargeable SIBs.
“Water-in-Salt” and Nasicon Electrolyte-Based Na-CO2 Battery
Authors: Im Eunmi , Kang Seok Ju , Moon Geon Dae
Published: July 2022

Aprotic electrolytes are much less feasible for producing cost-effective Na metal-based CO2 batteries due to high cost and flammability. As an alternative electrolyte, super-concentrated electrolytes, referred to as “water-in-salt (WiS) electrolytes”, have been received attention due to their wide electrochemical stability window, cost-effectiveness, and non-flammability. However, the highly reactive Na metal prevents the direct use of WiS electrolytes because the unsolvated water molecules would react with the Na Metal.

In this study, we demonstrated the ability of a WiS and NASICON electrolyte-based Na-CO2 battery for utilizing CO2 gas and serving as an energy storage cell. The NASICON separator allowed us to fabricate a hybrid Na-CO2 battery comprising Na metal as the anode material and WiS as the cathode electrolyte without damage of Na metal. Additionally, linear sweep voltammetry (LSV) with corresponding differential electrochemical mass spectroscopy (DEMS) measurements rendered the direct observation of H2 evolution retardation with increasing WiS concentration. Furthermore, we introduced a nano-sized Ru catalyst onto the current collector using Joule heating method for reducing the overpotential gap. Consequently, the Na-CO2 batteries with Ru@carbon current collector reduced the overpotential gap and exhibit a cycling endurance of over 75 cycles.

Figure 1
Constructing Favorable Microstructures in Solid-State Organic Cathodes Via Mechanical Property Manipulation
Authors: Chen Zhaoyang , Ai Qing , Lou Jun , Hadjiev Viktor G , Liang Yanliang , Yao Yan
Published: July 2022

Organic electrode materials, due to their low environment footprint and high material-level specific capacities, have become competitive alternatives to inorganic materials for solid-state batteries (SSB) in recent years. Additionally, the soft nature of organic compounds ensures consistent and intimate contact with solid sulfide electrolytes during cycling, which is beneficial for battery longevity. However, the low-modulus organic materials and high-modulus sulfide electrolytes, upon mixing and compression, would form unfavorable composite microstructure where sulfide particles are encapsulated by organics and cannot form an efficient ion conduction path. This mismatch in mechanical property prevents a high fraction of organic compounds to be used in a solid-state cathode, limiting the energy density of organic solid-state batteries.

Here we report the formation of favorable microstructures of organic cathodes by “softening” the sulfide electrolytes. Solvent treatment of the sulfide electrolyte Li6PS5Cl more than halves its modulus from 28.6 ± 8.5 GPa to 16.0 ± 1.6 GPa. Thermal gravimetric analysis, Raman spectroscopy, and X-ray diffraction were used to elucidate the evolution of the sulfide electrolyte during the softening and recovering process. The organic cathode formed by mixing organic materials with this softened electrolyte shows a favorable microstructure where the electrolyte forms a percolated domain. As a result, the utilization of an organic material, pyrene-4,5,9,10-tetraone (PTO), is increased by 133.6% and 90.8% compared with cells with a re-hardened and the pristine Li6PS5Cl, respectively. The mass fraction of PTO can be improved from 20 to 40wt% while maintaining high utilization (85.7%). Our exploration of softened electrolyte builds the correlation among structure, mechanical property, microstructure engineering and battery performance, and the strategy is applicable to other active materials with low modulus.
High-Capacity Cathodes for All-Solid-State Thin-Film Batteries
Authors: Hu Fei , Li Zhuo , West William , Tenhaeff Wyatt
Published: July 2022

Lithium-ion batteries (LIBs) are critically important rechargeable energy storage devices, finding widespread application in consumer electronics and electric vehicles. However, safety issues associated with their flammability impede their development for many applications. As a fully solid-state device, the thin film battery (TFB) is a compelling candidate for advanced microscale applications, including wearable devices, smart ID cards, and microelectromechanical systems (MEMS). A typical TFB design consists of solid thin films of crystalline cathode, amorphous LiPON electrolyte, Li metal anode and current collectors supported on a rigid substrate. Polycrystalline cathodes are often employed, such as LiCoO2, Li2Mn2O4, LiNiO2, V2O5, etc., because they provide high specific capacity and good reversibility. However, these cathodes require thermal treatment to generate the crystalline microstructure for optimal electrochemical performance, demanding substrates that are stable to several hundreds of degrees Celsius. The industry is interested in lower-cost, flexible all-solid-state thin-film batteries that can be readily integrated into a wide range of applications, including wearable devices. Thus, there is strong demand for thin film cathodes that can be processed at low temperatures.

Herein, we report a new amorphous inorganic thin-film cathode material, which is a solid state composite of Li2RuO3 and LiCoO2. (LRCO). Without any post-deposition annealing steps, as-deposited LRCO thin films possess a high discharge capacity of over 110 µAh cm-2 µm-1 at 0.3 C and capacity retention over 92% after 150 cycles owing to both cationic and anionic (oxygen oxidation) redox processes, which is competitive with conventional polycrystalline thin-film cathodes. The surface of LRCO cathode is smooth and isotropic, leading to uniform Li ion transport and thereby reducing the possibility of short-circuiting. More importantly, the entire preparation process is conducted at room temperature, enabling wider substrate options for TFBs, such as Kapton® films, polyethylene terephthalate (PET) films, or even paper sheets. Using PET plastic sheets to support LRCO TFBs; a specific capacity of 101 µAh cm-2 µm-1 at 0.3 C and capacity retention of 97.5% after 120 cycles was achieved, even when the substrate was mechanically bent (flexed).
Li Metal Anode Stabilized By Artificial Solid Interphase with Polymers of Intrinsic Microporosity
Authors: Kim Hyun Jong , Kim Hansu
Published: July 2022

Lithium metal has drawn attention as one of the most promising anode materials because of its highest specific capacity and lowest working potential. However, poor capacity retention and dendrite formation during cycling mainly caused by high chemical reactivity of Li metal with the electrolyte still remain challenges for practical battery application. In this presentation, we demonstrate that polymers of intrinsic microporosity(PIM-1) is highly effective in stabilizing the interface between Li metal anode and the electrolyte as an artificial solid interphase using various analytical techniques and electrochemical characterization techniques. We found a desolvation effect of electrolyte by PIM-1 coating through size-sieving, thereby forming the uniform and stable lithium deposition during cycling. Highly stable artificial solid interphase with polymers of intrinsic microporosity improved the interfacial stability and electrochemical performance of Li metal anode. The electrochemical performance and morphological change of lithium metal anode will be discussed in more detail in the presentation.
Fluorine Doped so2 Based Nonflammable Inorganic Electrolytes for Li Metal Batteries
Authors: Lee Jiwhan , Choi Seong Hoon , Mun Seung Do , Kim Hansu
Published: July 2022

Lithium metal batteries (LMBs) gained much attention as promising candidates for next generation energy storage devices because of their high-energy-density. Nevertheless, lithium dendrite growth during lithium plating/stripping hinders the practical uses of LMBs. Safety concerns such as flammability and unstable solid electrolyte interface (SEI) on lithium metal are also major problems to be solved. In this presentation, we report LMBs based fluorine doped LiAlCl4-xFx-3SO2 nonflammable inorganic liquid electrolyte. We will show how fluorine doping impact the electrochemical performance of LMBs with SO2 based inorganic liquid electrolyte. Detailed reaction mechanism of our battery system with F doped LiAlCl4-xFx-3SO2 nonflammable inorganic liquid electrolyte will be discussed in the presentation.
Three-Dimensional Carbon-Catalyst As Sulfur Host for Polysulfide Regulation in Lithium-Sulfur Batteries
Authors: Deng Wenjing , Wang Xiaolei
Published: July 2022

The ever-growing industrial society demand for limited natural resources and global energy consumption have given rise to the fast development of renewable energy storage technologies. Rechargeable batteries are considered to be indispensable for storing the supply of clean-but-intermittent energy sources, including solar and wind, in an efficiently and economically viable manner. Specifically, lithium-ion batteries (LIBs) with the reliable power capability and relatively mature storage mechanisms are commercialized in the market. However, due to shortage, high prices of lithium minerals, the physical energy density limits of innately available crystal sites, LIBs are unlikely to satisfy the need for grid-scale energy storage system in the long run. The urgent research for alternative sustainable energy storage device has led to the study of lithium-sulfur batteries (LSBs). With the new chemistries based on multi-electron conversion reaction between sulfur and lithium, LSBs are attracting great attention owing to large theoretical energy density of 2600 W h kg−1, high natural abundance and low cost of the sulfur source. Yet, despite their intriguing virtues, the fulfillment of sulfur electrochemical performance is perplexed by several intractable challenges that cause undesirable capacity fading and cycling life. Triggered by continuous round-trip diffusion in ether-based electrolyte, the shuttling effect of highly active lithium polysulfides (LiPSs) will eventually cause severe sulfur loss, electrode decomposition, and Coulombic inefficiency in LSBs. Targeting this issue, we proposed the synthesis of a novel sulfur host in cathode based on a honeycomb-like, porous nitrogen-doped carbon network consisting of MoC with three-dimensional architecture as sulfur host to suppress the shuttling behavior of LiPSs. Benefiting from the interconnected carbon with strong physical adsorption and MoC planes as catalytic sites for acceleration of redox kinetics. We demonstrated experimentally here that this sulfur reservior could realize the improved cell performance with high electronic conductivity, excellent sulfur chemisorption, high rate capacity with 1316 at 0.1 C, 646mAh g-1 at 3C, and long cycling stability with a small capacity decay rate.
(Digital Presentation) Mn-VOH Micro Flakes Interconnected with CNT As Cathodes for Aqueous Zinc-Ion Batteries
Authors: Gull Sanna , Huang Shao-Chu , Ni Chung Sheng , Liu Shih , Lin Wei-Hsiang , Chen Han-Yi
Published: July 2022

With increasing energy consumption and environmental awareness, the demand for next-generation energy storage systems has grown. Aqueous zinc-ion batteries (AZIBs) have received considerable attention among various types of energy storage devices due to their high safety standards and low cost. Herein, we present a sustainable synthesis approach for synthesizing MnVOH@CNT composite material and its application as the cathode material for aqueous Zinc-ion batteries (AZIBs) by using a low-temperature (120 °C) hydrothermal process. Moreover, with a continuous network structure and expanded interlayer spacing, such a configuration can provide rapid electron transfer kinetics (DZn
2+: 10 ̶ 11−10−12 cm2 s−1) while ensuring close interaction between MnVOH and CNT during cycling. The materials have excellent electrochemical properties as cathodes in the AZIBs. The resultant batteries exhibit a high intercalation storage capacity of c.a. 380 mAh g−1 at acurrent density of 0.1 A g−1, minimized polarization, and excellent capacity retention of c.a. 90% after 300 cycles. Furthermore, operando synchrotron X-ray absorption, near-edge spectroscopy was used for the first time to confirm the Zn2+ charge-storage mechanism. Operando synchrotron X-ray diffraction, studies were also done to better understand the structural changes of the MnVOH@CNT nanocomposite during the discharge/charge processes. Meanwhile, the ZIBs using MnVOH@CNT as cathode can maintain an energy density of c.a. 190 Wh kg−1 at a high power density of 3.2 kW kg−1, demonstrating that MnVOH@CNT is a promising cathode material for high-performance cathode material for low-cost and environment-friendly AZIB applications.

KEYWORDS: AZIB, MnVOH@CNT, operando XANES, operando XRD, cathode material
Using High Energy X-Ray White Beam Tomography to Quantify the Location and Morphology of ZnO Discharge Products in Alkaline Batteries
Authors: Guida Dominick P. , Gallaway Joshua W.
Published: July 2022

In alkaline Zn anodes, the active material is discharged to both aqueous zincate ions and solid ZnO. The mobility of zincate in the electrolyte allows considerable transport of the discharge products, which can form directly on the Zn active material or far from it, effectively relocating material long distances inside the cell. Additionally, ZnO can exist in more than one form, namely type I and type II, which differ in their density and passivating character.1 This leads to complex compositions of discharged primary Zn anodes and can cause cell failure due to redistribution of Zn in rechargeable cells. Models of Zn anodes are typically designed for continuous discharge,2 yet real-world use conditions usually involve intermittent discharge. Therefore, the ability of these models to predict ZnO morphology and distribution for cells used in real-world applications is questionable.

It has been previously reported that when alkaline AA cells are discharged, ZnO forms passivating shells around undischarged Zn cores. At high discharge rates, this passivation of Zn increases in severity and hinders cell performance. Additionally, higher discharge rates increase the non-uniformity of ZnO distribution within the anode, preferentially precipitating ZnO near the separator which impedes hydroxide transport from the cathode to the inner portion of the anode.3 In this work, we analyze cylindrical cells discharged using intermittent profiles that approximate real battery use. We then compare the ZnO distribution to that found after continuous discharge.

Synchrotron X-ray tomography was used to obtain in situ volumetric reconstructions at a spatial resolution of 3 microns. To observe the spatial distribution and morphology of ZnO formation in partially discharged Zn anodes, multiple AAA cells were discharged using distinct protocols. When using a continuous discharge, the reconstructions verified previous findings that core-shell structure is the primary morphology of ZnO and is non-uniformly distributed towards the separator.3 However, a radically different morphology and spatial distribution of ZnO was observed when using an intermittent discharge protocol. Specifically, when providing an 8 hour rest after each hour of discharge, ZnO forms isolated clumps distributed throughout the anode. Using this intermittent discharge protocol avoids passivating active material and potentially enables a higher Zn utilization by minimizing isolation of active material.

References

[1] I. Arise et al 2013 J. Electrochem. Soc. 160 D66

[2] E. J. Podlaha and H. Y. Cheh 1994 J. Electrochem. Soc. 141 15

[3] Quinn C. Horn and Yang Shao-Horn 2003 J. Electrochem. Soc. 150 A652
(Digital Presentation) Understanding Kinetics of Metal Dissolution from Integrated Multiscale Simulations and Experiments
Authors: Sharma Shubham , Weitzner Stephen Eric , Shi Rongpei , Zagalskaya Alexandra , Cho Seongkoo , Eggart Lisa , Alexandrov Vitaly , Orme Christine , Pham Anh Tuan , Wood Brandon C.
Published: July 2022

Understanding dissolution kinetics is essential for predicting and mitigating materials corrosion; however, many mechanistic details still remain enigmatic. Examples include the evolution of solvation properties of ions and nature of electron transfer during dissolution. In this work, we integrate high-fidelity first-principles calculations based on grand-canonical density functional theory (DFT) and mesoscale simulations to predict dissolution kinetics of aluminum metal in acidic conditions. First, we show that the inclusion of an explicit solvation shell is crucial for accurately predicting the redox potential of metal dissolution. Second, we show that metal dissolution is governed by two kinetically limited processes, which are associated with the metal-metal bond breaking and ion diffusion within the electric double layer. Interestingly, it is found that kinetics and thermodynamics of these processes can be described with a simple model functionally based on Marcus theory, and their relative importance can be switched, depending on the applied potentials. Third, we show how dissolution kinetics derived from DFT is integrated with mesoscale simulations to elucidate the role of microstructure on the global metal dissolution. Comparison with experimental measurements will also be discussed.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported with Laboratory Directed Research and Development funding under Project 20-SI-004.