bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Development of Highly Luminescent Radical Core Carbazole Dendrimer
Authors: Albrecht Ken
Published: July 2022

The development of emitting materials for OLEDs has started with fluorescence, moved to phosphorescence, and reached TADF. These materials have singlet ground state, but recently some ground state doublet (radical) emitting materials have been reported.1,2 The excited state of doublet emitters also has a doublet character, and theoretically, can achieve 100% exciton utilization efficiency in an OLED device. Triphenylmethyl radicals such as PTM (perchlorotriphenylmethyl) radical were recognized as emitters from the 1980s. The photostability of these radicals are extremely low, but in 2006 the introduction of donor (carbazole) unit was reported to improve the photostability and opened the door to utilize them as a luminescent materials.3

Carbazole dendrimers are widely used as solution-processable OLED material including TADF emitters.4 The dendron has a highly polarized unique electronic structure due to the summation of the inductive electron-withdrawing effect of carbazole units.5 The attachment of carbazole dendrons to luminescent radical is expected to increase the stability through the steric and electronic effects.

A carbazole dendron (G2 to G4) attached TTM (tris(2,4,6-trichlorophenyl)-methyl) radicals were successfully synthesized and photophysical parameters were determined. All dendrimers showed red emission. PLQY (photoluminescence quantum yield) increased when the generation increased and reached 80%. The major reason was the decrease in the internal conversion rate (non-radiative decay). The photostability (PL intensity half-life measured under continuous laser irradiation) in solution has increased 100 to 1000 times compared to simple TTM radicals. These results indicate that the carbazole dendron attached TTM radicals are potential material for efficient OLEDs.

References

[1] Q. Peng, A. Obolda, M. Zhang, F. Li, Angew. Chem. Int. Ed.
2015, 54, 7091.

[2] X. Ai, E. W. Evans, S. Dong, A. J. Gillett, H. Guo, Y. Chen, T. J. Hele, R. H. Friend, F. Li, Nature
2018, 563, 536.

[3] V. Gamero, D. Velasco, S. Latorre, F. Lopez-Calahorra, E. Brillas, L. Julia, Tetrahedron Lett.
2006, 47, 2305.

[4] K. Albrecht, K. Matsuoka, K. Fujita, K. Yamamoto, Angew. Chem. Int. Ed.
2015, 54, 5677.

[5] K. Albrecht, K. Yamamoto J. Am. Chem. Soc.
2009, 131, 2244.
(Invited) Simulating Dynamic Excitons Via Quantum Molecular Dynamics: A Case Study in Lead Halide Perovskites
Authors: Uratani Hiroki
Published: July 2022

The ultrafast electronic and structural dynamics invoked by photoexcitation, i.e., “dynamic exciton” phenomena, not only are important in the context of practical applications such as solar cells, but also raise many questions from the viewpoint of fundamental science. Experimental measurement, computational simulations, and theoretical interpretation will be the three pillars for deciphering the dynamic exciton phenomena.

From the viewpoint of computational simulations, molecular dynamics (MD) techniques combined with quantum chemical calculations, i.e., quantum molecular dynamics (QMD), has been the popular tool to simulate the dynamic exciton phenomena. The quantum chemical calculations, which are typically conducted on the basis of the density-functional theory (DFT), require the large computational resources and time. These have been the limiting factors for the accessible spatial and time scales by the QMD simulations.

To extend the coverage of simulations to more complex, large-scale systems, we have developed efficient excited-state QMD methods that can include nonadiabatic effects. Our method combines the density-functional tight binding (DFTB) method, which is an approximate DFT, and the surface hopping method, which is a theoretical framework to incorporate the nonadiabatic effects into the QMD simulations. The method was further improved to be suitable for condensed-phase simulations explicitly including the environment, i.e., solvent, by using a “divide-and-conquer” style quantum chemical calculation technique. These theoretical framework enables us to simulate the coupled electronic–structural dynamics in excited states of systems consisting of 102–103 atoms[1,2,3].

In addition, using the developed method, we conducted the real-time simulations of the ultrafast processes invoked by photoexcitation of lead iodide perovskites, which are known as the key materials for perovskite solar cells. The dissociation of the exciton into the positive and negative charge carriers was observed. Moreover, the hot carrier cooling, where the charge carriers dissipate excess energy via the electron–phonon coupling and relax to the band edges, was also tracked. Finally, the direct evidence of the polaron formation, where the structural deformation is induced by the presence of charge carriers, was observed. These results highlight the importance of the coupling between electronic and structural degrees of freedom.

In the talk, recent improvements in the methodology and future perspectives will also be presented[5].

References

[1] H. Uratani and H. Nakai, J. Chem. Phys.
152, 224109 (2020).

[2] H. Uratani, T. Morioka, T. Yoshikawa, and H. Nakai, J. Chem. Theory Comput.
16, 7299 (2020).

[3] H. Uratani, T. Yoshikawa, and H. Nakai, J. Chem. Theory Comput.
17, 1290 (2021).

[4] H. Uratani and H. Nakai, J. Phys. Chem. Lett.
11, 4448 (2020).

[5] H. Uratani and H. Nakai, J. Chem. Theory Comput. in press.

Figure 1
(Invited) Cascaded Energy Landscape As a Key Driver for Slow Yet Efficient Charge Separation with Small Energy Offset in Organic Solar Cells
Authors: Tamai Yasunari
Published: July 2022

Recent studies have shown that efficient free carrier (FC) generation with a small voltage loss can be achieved in organic solar cells (OSCs); however, the photophysical insights underpinning this remain unclear. I will talk about the mechanisms underlying the FC generation in a state-of-the-art OSC consisting of PM6 and Y6 as an electron donor and acceptor, respectively, wherein the energy offset between the lowest excited singlet state and the charge transfer state is as small as ~0.1 eV. In this study, transient absorption spectroscopy was used to track the time evolution of electroabsorption caused by electron–hole pairs generated at donor/acceptor interfaces. After hole transfer from Y6 to PM6, slow yet efficient spatial charge dissociation on a time scale of picoseconds was observed. Based on temperature dependence measurements, it is found that this slow yet efficient FC generation is driven by downhill energy relaxation of charges through the energy cascade generated near the interfaces.
Chromophore Nanohybrids for Sensing and Singlet Oxygen Generation
Authors: Hill Jonathan P.
Published: July 2022

Nanohybrid materials can exhibit the physical properties of their components and be used in various applications. Also, novel chromophores involving synthetically flexible molecules such as pyrazinacenes1 and porphyrins2 can be incorporated into these structures by different means in particular as MOFs or COFs, while other components include simple transition metal salts or oligonuclear metal-oxo clusters. In this work, we discuss nanohybrids materials containing oxoporphyrinogen (OxP), tetrapyrroles or fullerene as the organic component, with hybridization using respectively Ag(I) salt or oxo-Zr(IV) cluster. This yields nanohybrid materials having structures and properties due to their individual components. Highly-colored OxP is a tetrapyrrole macrocycle which can be stimulated to generate reactive singlet oxygen (1O2) under appropriate conditions (1O2 can be used for applications such as photodynamic therapy and environmental remediation). 1O2 generation by OxP undergoes significant enhancement over its unhybridized state when incorporated in nanohybrid structures, either MOFs or COFs, containing respectively oxo-Zr(IV) nodes or electron deficient linkers in porous coordination polymer nanoarchitectures. OxP-oxoZr(IV) nanohybrid can then be applied for oxidation of small molecule substrates to selected products.3 Also, C60 fullerene can be co-crystallized with silver(I) nitrate at the molecular level4 leading to a material that exhibits unique properties during its decomposition so that silver nitrate is released with concurrent deposition of highly nanostructured C60-only crystalline networks. The resulting nanohybrid material has been studied for application as slow-release antibacterial material.4 Other work includes porous materials for sensing applications. The utility of the nanohybrid approaches is demonstrated by using these examples.

References: 1) G. J. Richards, J. P. Hill, Acc. Chem. Res., 2021, 54, 3228–3240. 2) M. K. Chahal, A. Liyanage, A. Z. Alsaleh, P. A. Karr, J. P. Hill, F. D'Souza, Chem. Sci., 2021, 12, 4925–4930. 3) J. Hynek, D.T. Payne, M.K. Chahal, F. Sciortino, Y. Matsushita, L.K. Shrestha, K. Ariga, J. Labuta, Y. Yamauchi, J.P. Hill, Mater. Today Chem., 2021, 21, 100534. 4) J. P. Hill, R. G. Shrestha, J. Song, Q. Ji, K. Ariga, L. K. Shrestha, Bull. Chem. Soc. Jpn., 2021, 94, 1347–1354.
Molecular Lego for Functional 2D Materials: Self-Assembly and Ordering of Bi-Molecular 2D Spinlattices of M(II,III) Phthalocyanines and of Highly Crystalline Free Standing Networks
Authors: Baljozovic Milos , Liu X. , Moradi Mina , Pasti Igor A. , Dreiser Jan , Decurtins Silvio , Shahgaldian Patrick , Liu Shi Xia , Jung Thomas A.
Published: July 2022

Single layer low-dimensional materials are presently of emerging interest, also in the context of magnetism. We further developed on-surface supra-molecular architecturing to create two-dimensional spin arrays. By chemical programming of the modules, different checkerboards were produced containing metals of different oxidation and spin states, diamagnetic zinc, and a metal-free ‘spacer’. [1] In an in-depth, spectro-microscopy and theoretical account, we correlate the structure and the magnetic properties of these tunable systems and discuss the emergence of 2D Kondo magnetism [2] from the spin-bearing components and via the physico-chemical bonding to the underlying substrate. The contributions of the individual elements, as well as the role of the electronic surface state in the bottom substrate, are discussed. Also we show the the first free-standing single layer networks of calixarenes stabilized via functional groups enabling vdW, coordination and dipole-dipole, interaction. [3]

Fig. 1) Graphical animation of the 2D spin arrays built by C--H - F--C bonding of two different magnetic atom bearing phthalocyanines that have been exploited to investigate the assembly and properties of Kondo lattices.

[1] M. Baljozovic et al. Magnetochemistry 2021, 7, 119.

[2] J. Girovsky et al. Nature Communications 2017 8:15388

[3] M. Moradi, N. Opara, L.G. Tulli, C. Wäckerlin, S.J. Dalgarno, S.J. Teat, M. Baljozovic, O. Popova, E. van Genderen, A. Kleibert, H. Stahlberg, J.P. Abrahams, C. Padeste, T.A. Jung, P. Shahgaldian, Sci. Adv. 2019; 5: eaav4489

Figure 1
Electrochemistry of Innocent and Noninnocent Metallocorroles
Authors: Osterloh William Ryan , Kadish Karl , Desbois Nicolas , Brandès Stéphane , Gros Claude
Published: July 2022

Our laboratories have long been interested in the redox properties of four-, five- and six-coordinate metallocorroles (Chart 1) with different donor axial ligands and a variety of peripheral corrole substituents. In this work, we describe and compare our most recent results on different transition metal derivatives containing highly electron withdrawing substituents at the meso-positions of the macrocycle.

Figure 1
Structure and Properties of Cu-Phthalocyanine-Based Molecular Solids from First Principles
Authors: Kronik Leeor
Published: July 2022

Cu-phthalocyanine based molecular solids are widely used in various areas, from paints to optoelectronics. While much theoretical effort has been directed at the Cu-phthalocyanine molecule and its derivatives, molecular solids have not been studied in as much detail. Here, we present a first principles study, based on advanced approaches within density functional theory, that considers the structure of various Cu-phthalocyanine polymorphs and assesses the ensuing electronic structure.
Agricultural Waste-Derived Nanoporous Carbon As Electrode Material for High-Power Plant Microbial Fuel Cell
Authors: Lin Yao-Yu , Li Hsin-Tien , Chen Han-Yi , Liu Tzu-Yin
Published: July 2022

Developing environment-friendly and sustainable energy is urgent these days, as it can solve energy shortages and the pollution that come from fossil fuel. Therefore, Plant microbial fuel cells (PMFCs) start to get attention recently. PMFC is a novel technology that can convert chemical energy into electricity by using microbial in the rhizosphere of plants without producing harmful byproducts during the process. However, PMFCs suffer from some practical issues such as low power output and high costs of electrode materials. This gives rise to the progress of electrode material which can improve the power output and reduce the cost.

To break through the limits of PMFCs, the agricultural waste-derived carbons were prepared and optimized as the anode material in our self-designed Canna-indica PMFCs in this study. Green carbon materials utilizing agricultural waste as precursors are not only environment-friendly but also a part of circular economy which helps to mitigate bio-waste and improve society sustainability. The biowaste-derived activated carbon materials were characterized by Brunauer-Emmett-Teller (BET) surface area analyzer, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The high surface area, porosity morphology, and good conductivity of the biowaste-derived activated carbon are the promising characteristics of high-performance anode materials of PMFCs. The maximum power density of our self-made PMFC device can reach 61 mW m−2. The average power density was maintained at 23 mW m−2 during the long-term measurement. All of the results in this study demonstrate the potential of using agricultural waste as electrode material for improving the electricity production of PMFCs.
Teesmat an Open Innovation Test Bed for Electrochemical Devices: Example of X-Ray Nano-Tomography As Characterization Tool for Battery Analysis
Authors: Vanpeene Victor , Drnec Jakub , Schulli Tobias , Capria Ennio , Villanova Julie
Published: July 2022

The recent rapid increase of the demand of higher energy density along with higher power density lithium-ion batteries (LiBs) requires the development of advanced cathode/anode materials with higher capacity. These challenges can be addressed providing that powerful characterization tools are able to probe the degradation phenomena occurring at multiple scale. In this context, the TEESMAT platform aims to widen the access to a large panel of characterization techniques among different partners across Europe for solving industrial problematics in energy related field. Among these, X-ray tomography has been used as non-invasive 3D investigation tool that spread along a wide range of applications in order to probe at different length scale their microstructure. Moreover, phase contrast imaging has brought to light a practical way to enhance visibility between weak absorbing materials and/or small details of differing refractive index within structure, and thus accessing a sharpen overview of the 3D morphology of complex material, which is of particular interest in the frame of energy-related materials.

This presentation will focus on various industrial case studies such as NMC-based and LFP-based all solid-state batteries, hybrid Li-ion supercapacitor and current collector manufacturing.

The results presented are part of the TEESMAT project, which received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 814106.
Using High Field Model to Interpret Potentiodynamic Polarization Curves of AA7075 at High Scan Rates
Authors: Zhou Hu , Mauzeroll Janine
Published: July 2022

The drastic distortion of potentiodynamic polarization curves measured at high potential scan rates prevents the extraction of accurate kinetic parameters. By measuring potentiodynamic polarization curves of AA7075 at scan rates ranging from 0.167 mV/s to 100 mV/s, in an acidic solution of 0.62 M NaH2PO4 and a near-neutral 3.5 wt% NaCl solution, changes in potentiodynamic polarization curves are observed not only at different scan rates and electrolytes but also between replicated experiments. Contrary to what was reported in previous studies, the disturbance of charging current associated with high scan rates does not satisfactorily explain the potentiodynamic polarization shape. Instead, the high field model that incorporates the kinetics of anodic oxide growth successfully captures the features of experimental potentiodynamic polarization curves. Compared to Tafel’s theory, the high field model explains remarkably both the changing kinetics with scan rates, electrolytes, and the variance between the measurement performed at different sites.

Figure 1
Evaluation of Counter and Reference Electrodes for the Investigation of Ca Battery Materials
Authors: Liu Xu , Elia Giuseppe , Passerini Stefano
Published: July 2022

The massive demand for batteries required by electromobility and stationary storage is pushing the research activity to evaluate electrochemical storage chemistries based on highly abundant elements, as alternatives to state-of-the-art Li-ion ones.[1] The use of more abundant and sustainable elements is expected to reduce the cost and the environmental impact of the energy storage devices. In particular, calcium, the fifth most abundant element in the Earth’s crust also offering non-toxicity, low standard reduction potential (-2.87 vs. SHE), is an appealing candidate for the realization of electrochemical storage devices.[1] However, the conditions to achieve efficient Ca stripping and deposition have not been found yet, due to the formation of passivation products at the Ca/electrolyte interphase, blocking any electrochemical reaction.[2] Although a limited number of electrolytes enabling the stripping deposition have been found, [3–6] they are characterized by a rather limited efficiency, thus making the Ca metal unsuitable for counter and reference electrodes. The resulting lack of a reliable cell configuration limits the possibility to test candidate electrode materials suitable for Ca2+-based electrochemical storage devices, impeding the progress and research on the topic. Here, we propose an alternative cell configuration, employing activated carbon (AC) as counter electrode and quasi reference electrode (QRE), as a reliable system for the electrochemical characterization of electrode materials for Ca-ion batteries.[7] As a prove-of-the-concept, a few electrode materials, i.e., CaV6O16 cathode and graphite anode exploiting co-intercalation mechanism, have been demonstrated electrochemically active in Ca2+-based electrolytes.

References:

[1] M.E. Arroyo-De Dompablo, A. Ponrouch, P. Johansson, M.R. Palacín, Achievements, Challenges, and Prospects of Calcium Batteries, Chem. Rev. 120 (2020) 6331–6357.

[2] D. Aurbach, R. Skaletsky, Y. Gofer, The Electrochemical Behavior of Calcium Electrodes in a Few Organic Electrolytes, J. Electrochem. Soc. 138 (1991) 3536–3545.

[3] A. Ponrouch, C. Frontera, F. Bardé, M.R. Palacín, Towards a calcium-based rechargeable battery, Nat. Mater. 15 (2016) 169–172.

[4] D. Wang, X. Gao, Y. Chen, L. Jin, C. Kuss, P.G. Bruce, Plating and stripping calcium in an organic electrolyte, Nat. Mater. 17 (2018) 16–20.

[5] A. Shyamsunder, L.E. Blanc, A. Assoud, L.F. Nazar, Reversible Calcium Plating and Stripping at Room Temperature Using a Borate Salt, ACS Energy Lett. 4 (2019) 2271–2276.

[6] Z. Li, O. Fuhr, M. Fichtner, Z. Zhao-Karger, Towards stable and efficient electrolytes for room-temperature rechargeable calcium batteries, Energy Environ. Sci. 12 (2019) 3496–3501.

[7] X. Liu, G.A. Elia, S. Passerini, Evaluation of counter and reference electrodes for the investigation of Ca battery materials, J. Power Sources Adv. 2 (2020) 100008.
Development of Stable Layered Oxide Cathode Materials Assisted By Machine Learning for K-Ion Batteries
Authors: Hwang Jang-Yeon , Kim Jaekook
Published: July 2022

Recently, the emergence of an artificial intelligence method, especially a machine-learning (ML) approach, has shown its potential to accelerate research and development for materials science. On the other hand, density functional theory (DFT) calculations have the ability to predict materials properties with relatively high accuracy.1 In the field of battery researches, using traditional methods, such as the empirical trial and error methods, hinders the development of new advanced electrode materials, particularly in potassium-ion batteries (KIB).2-4 To address this issue, here we develop for the first time a protocol using a combined ML and DFT calculations for materials screening followed by experimental verification. Notably, layered oxide cathode materials, such as KxMnO2, which have been widely investigated for KIB due to their high energy and power densities, suffer from structural instability and highly hygroscopic nature. Therefore, this proposed protocol is used for designing structurally stable KxMnO2 with enhanced environmental stabilities and high electrochemical performances. Among the numbers of candidates, notably, the ML and DFT-assisted strategies identify P′3-type K0.3Mn0.9Cu0.1O2 (KMCO) as a promising cathode for a high-performance KIB application. Finally, the experimental results further prove that the KMCO cathode has substantially improved K-storage properties with high-power density and cycling stability even after 4-week air-exposure period. We believe that this study opens a new avenue for identifying and developing suitable electrode materials for future battery applications.

References

B. Scrosati, M. Bottini and T. Mustelin, Nanotechnol., 2007, 2, 598 —599.

N. Yabuuchi, K. Kubota, M. Dahbi and S. Komaba, Chem. Rev., 2014, 114, 11636 —11682.

A. Eftekhari, Z. Jian and X. Ji, ACS Appl. Mater. Interfaces, 2017, 9, 4404 —4419.

N. Xiao, W. D. McCulloch and Y. Wu, J. Am. Chem. Soc., 2017, 139, 9475 —9478
(Digital Presentation) Cooperative Radial Corrosion- and Pressure-Assisted Stress Buildup in High Pressure Pipes
Authors: Aryanfar Asghar , Marian Jaime
Published: July 2022

The corrosion in the pressurized pipelines catastrophic event, specifically in the light water reactors, ultimately leading to the failure and fracture. We develop a real-time framework for the accumulation of compressive stresses due to both corrosion (i.e. plastic) and external pressure (i.e. elastic) events. In this regard, we quantify the infiltration of the oxygen in the metal matrix within the curved boundary and establish the stoichiometrically equivalent resulted oxide thickness. Subsequently, we quantify the real-time augmentation in the volume due to oxide formation and we analytically calculate the resulted stress build-up. Combining the build-up stress with the original stress built-up due to external pressure provides the total imposed compressive stress into the material as the estimate for the onset of the failure. The developed analytical framework could be utilized for estimating the design parameters for safe operation of transport pipes, particularly in applications related to the high-pressure and highly-corrosive environments.

Figure 1
Sodium All-Solid-State Batteries and the Electrolyte Question
Authors: Goodwin Laura E. , Bhardwaj Monika , Till Paul , Nazer Nazia , Richter Felix H. , Janek Jürgen
Published: July 2022

As the need for green energy storage increases, the development of solid-state sodium batteries is pushed forward. Main advantage towards lithium-ion batteries is that sodium is an element that is abundant and ubiquitous. Recent studies have developed sodium ion conducting solid electrolytes with a conductivity of 4∙10-2 S cm-1, which exceeds the ionic conductivity of lithium ion conductors at room temperature. As solid electrolytes are immobile, the possibility of using different electrolytes as separator and catholyte according to their useful properties presents itself. Nasicon (Na3.4Zr2Si2.4P0.6O12) material as a ceramic has a high ionic conductivity however lacks mechanical flexibility. Sulfur electrolytes such as Na2.9Sb0.9W0.1S4 predominate with their high elastic modulus and at the same time high ionic conductivity, however, show major electro-chemical instabilities in contact with the electrodes. The halide type electrolytes show their strength in term of stability, but have not reached relevant ionic conductivities yet. The combination of different electrolytes and the electrochemical implications are presented in this study. Chemical, electrochemical and mechanical stabilities are tested and monitored in full and symmetric sodium tin alloy cells.
Interface Engineering Via Fluorinated Solid Electrolytes for All-Solid-State Li Batteries
Authors: Zhang Shumin , Zhao Feipeng , Sun Xueliang Andy
Published: July 2022

Solid electrolytes (SEs) are vital for all-solid-state batteries (ASSBs) since they replace the flammable liquid electrolytes to make the ASSBs safer and compacter.1 In order to boost the energy density of ASSBs, a practical SE is not only expected possessing high ionic conductivity, but also good compatibility with both cathode and anode to allow the use of high-voltage cathode and Li metal.2, 3 However, most of the developed SEs show limitations on directly contact with either high-voltage cathode materials or Li metal. As such, SE modification is required to address the interfacial issues between SE and electrodes.

In this work, fluorinated sulfide- and halide-based SEs are proposed to stabilize the SE/Li metal and SE/high-voltage cathode interfaces, respectively. Our results firstly show that fluorinated argyrodite Li6PS5Cl (LPSCl) can enhance the interfacial stability toward the Li metal anode.4 The in-situ formed interface between Li and LPSCl1−xFx are of highly fluorinated and condense, which enables ultrastable Li plating/stripping behavior over 250 hrs at a high current density of 6.37 mA cm−2 and a cutoff capacity of 5 mAh cm−2. The Li metal treated by the LPSCl1−xFx SE is then demonstrated to deliver good durability and rate capability in full cells. Other than anode side improvement, F is introduced into a superionic conductor Li3InCl6 to widen the oxidation limit to over 6 V (vs. Li/Li+).5 Both experimental and computational results identify that F-containing passivating interphases are generated to contribute to the enhanced oxidation stability of Li3InCl6-xFx and stabilization the surface of cathodes at high cut-off voltages. The optimized composition Li3InCl4.8F1.2 is directly matched with bare high-voltage LiCoO2, enabling ASSBs to stably operate at room temperature at a cut-off voltage of 4.8 V (vs Li/Li+). Our studies provide a new strategy of interface engineering by introducing F in SEs, realizing the good compatibility between SE and electrodes and opening up the applications of ASSBs.

Re
ferences

Manthiram, A., Yu, X. W., Wang, S. F. Lithium battery chemistries enabled by solid-state electrolytes. Nat. Rev
.
Mater.
2, 1-16 (2017).

Wang, C. H., Liang, J. W., Zhao, Y., Zheng, M. T., Li, X. N., Sun, X. L. All-solid-state lithium batteries enabled by sulfide electrolytes: from fundamental research to practical engineering design. Energy Environ. Sci.
14, 2577-2619 (2021).

Li, J. C., Ma, C., Chi, M. F., Liang, C. D., Dudney, N. J. Solid Electrolyte: the Key for High-Voltage Lithium Batteries. Adv. Energy Mater.
5, 1401408 (2015).

Zhao, F. P., et al. Ultrastable Anode Interface Achieved by Fluorinating Electrolytes for All-Solid-State Li Metal Batteries. ACS Energy Lett.
5, 1035-1043 (2020).

Zhang, S. M., et al. Advanced High-Voltage All-Solid-State Li-Ion Batteries Enabled by a Dual-Halogen Solid Electrolyte. Adv. Energy Mater.
11, 2100836 (2021).
New Insights on Electrochemical Parameters in Battery Modeling through 3D Digital Twin Structural Analysis
Authors: Lee Yong Min
Published: July 2022

Electrochemical parameters such as chemical diffusion coefficients and exchange current densities are very critical in simulating electrochemical battery models. However, conventional experimental methods have not reflect actual status of composite electrodes and cells due to the limitation in analyzing their micro-structures. To address these challenges, we attempted to draw 3D digital twin structures of composite electrodes and cells and then quantify veiled parameters like active surface area. As a result, we could obtain more correct chemical diffusion coefficients and exchange current densities and improve the reliability of electrochemical battery models. In this work, we will introduce how to build and use 3D digital twin structures of composite electrodes for lithium-ion batteries.

[References]

1. J. Park, Y. M. Lee et al., Energy Storage Materials, 19 (2019) 124-129

2. J. Park, Y. M. Lee et al., Advanced Energy Materials, 10(35) (2020) 2001563

3. J. Kim, J. Park, Y. M. Lee et al., ACS Energy Letters, 5(9) (2020) 2995-3004

4. J. Kim, S. Jung, Y. M. Lee et al., Advanced Energy Materials
, Online published (2021)
(Invited) Electrochemistry Based and Coupled Approaches for Characterization of Lithium Ion Battery Materials and Systems
Authors: Marschilok Amy C.
Published: July 2022

Lithium ion batteries represent a remarkable technological and commercial success, due to their lightweight and high energy density. However, to address future energy storage needs, there is a need for further research to understand and address lifetime limiting mechanisms. This presentation will highlight progress achieved via electrochemistry based and coupled methods for in-situ and operando characterization of lithium ion battery systems, spanning multiple material chemistries.
Electrolyte Development for Safe Li-Ion Battery Fast Charging: Decreasing Inactive Li on Graphite
Authors: Konz Zachary M. , Wirtz Brendan M. , Colclasure Andrew M. , Verma Ankit , McCloskey Bryan D.
Published: July 2022

Fast charging of lithium-ion batteries is limited primarily by the risks from lithium plating on the graphite anode. Plated lithium can become electrically isolated from the graphite (‘inactive Li’), causing rapid capacity fade and raising safety concerns. Thus, many studies have focused on detecting Li plating and designing operating conditions or materials to avoid it. Here we explore the reversibility of the lithium plating reaction as a tunable electrolyte property to mitigate inactive Li. We report a novel cycling technique to rigorously estimate the Li plating reversibility on graphite in Li/Graphite cells and then apply it to understand how additives, amount plated, and current density affect reversibility. Electrolyte compositions with reported high reversibility are tested under fast charging conditions in graphite/NMC cells, showing superior cycling performance and less inactive Li quantified by hydrogen gas evolution of extracted anodes. Finally, we consider limitations of reversibility measurements for Li plating/stripping on graphite and offer ways to address them.
(Digital Presentation) Understanding of Fast Charging in Li-Ion Batteries, an Operando Neutron Diffraction Study
Authors: Du Zhijia , Wu Xianyang , Liu Jue
Published: July 2022

Fast charging (<15 min) of lithium-ion batteries (LIBs) for electrical vehicles (EVs) is widely seen as the key factor that will greatly stimulate the EV markets, and its realization is mainly hindered by the sluggish diffusion of Li+. To have a mechanistic understanding of Li+ diffusion within LIBs, in this study, structural evolutions of electrodes for a Ni-rich LiNi0.6Mn0.2Co0.2O2 (NMC622) || graphite cylindrical cell with high areal loading are developed for operando neutron powder diffraction study at different charging rates. Via sequential Rietveld refinements, changes in structures of NMC622 and Li
x
C6 are obtained during moderate and fast charging (from 0.27 C to 4.4 C). NMC622 exhibits the same structural evolution regardless of C-rates. For phase transitions of Li
x
C6, the stage I (LiC6) phase emerges earlier during the stepwise intercalation at a lower state of charge when charging rate is increased. It is also found that the stage II (LiC12) → stage I (LiC6) transition is the rate-limiting step during fast charging. The LiC12 → LiC6 transition mechanism is further analyzed using the Johnson–Mehl–Avrami–Kolmogorov model. It is concluded as a diffusion-controlled, 1D phase transition with decreasing nucleation kinetics under increasing charging rates.
Liquid Electrolytes Enabling Ultra-High Fast-Charge in Lithium Metal Batteries with NMC-811 Cathodes
Authors: Baird Michael , Song Junhua , Tao Ran , Helms Brett
Published: July 2022

Batteries capable of fast charging rely on electrolytes that maximize ion mobility to allow redox reactions to proceed at the same rate electrons are transported between electrodes. Here I will describe our recent efforts in liquid electrolyte development to enable 80% change in state-of-charge in 15, 10, and 5 minutes in lithium metal batteries without irreversible damage to the cell. The effects of concentration, viscosity, ionic conductivity, and solvation effects on cycle life are investigated, revealing that electrolytes with the highest Li+ mobility minimize the fast-charge overpotential and enable the full capacity of the cell to cycle reversibly. We further show through detailed synchrotron hard X-ray microtomography and complementary scanning electron microscopy that such electrolytes also suppress ramified Li growth. We also perform detailed electroanalytical studies to quantify the remarkably slow rates of lithium consumption and point to dead lithium formation as a primary challenge for (ultra)-fast-charging lithium metal batteries.
Optimization of Catholyte in Composite Cathodes for Garnet-Structured Llzo Electrolyte in Solid-State Batteries
Authors: Houache Mohamed , Karkar Zouina , Yim Chae-Ho , Filoso Gina , Niketic Svetlana , Abu-Lebdeh Yaser
Published: July 2022

The application of Li-ion batteries have been expanding at a rapid rate in recent decades due to the tremendous demands in the market for portable electronics, smart grid, and electric vehicles (EVs). All-solid-state lithium metal battery (ASSLB) is the most promising next-generation energy storage device as they can solve the safety issue resulted from liquid electrolytes.

Among different types of solid-state electrolytes (SSE), garnet-type structure materials have been shown to be very promising for the development of ASSLBs owing to their high Li-ion conductivity (∼10–3 S cm–1 at RT), wide electrochemical stability window (∼6 V vs Li+/Li), and good chemical stability against Li metal. The high interfacial resistance generated by inadequate contact and interfacial reactions is a substantial impediment to the adaptation of ASSLBs. To address this challenge, a catholyte (a small amount of ionic conductors which are mostly derived from the solid electrolyte formulation) is introduced into the cathode formulation. This necessities a re-design of the cathode into a composite cathode with possibly new components such as carbon additives with high aspect ratio and conductive binders. Understanding their individual and combined impacts on performance is essential in the pursuit of optimized systems.

In this work, we designed a series of composite cathode formulations defined with three cathode active materials (LFP, NMC 622 and NMC 811), three carbonaceous additives (carbon black, carbon nanofibers and carbon nanotubes), and a series of organic and inorganic molecular, and polymeric conductors along with LLZO to create a composite cathode with high capacity and stability at high C-rates. A systematic DOE approach has been utilized to evaluate the impact of each component on the electrode and cell performance and the results will be presented.
Cyclic Carbonate-Based, Single-Ion Conducting Polymer Electrolytes for Li-Ion Batteries: Electrolyte Design
Authors: Engler Anthony , Park Habin , Liu Nian , Kohl Paul
Published: July 2022

Solid polymer electrolytes (SPEs) have been the focus of study to address Li-ion battery issues including thermal runaway by mitigating the danger from volatile solvents. A single ion conductor has a high transference number which eliminates uncontrolled mass transport by immobilizing the anion to the polymer matrix. Problems with undesired side reactions and lithium dendrite growth can also be improved by providing a mechanical barrier. Unfortunately, single-ion conducting SPEs suffer from poor lithium-ion mobility and conductivity due to the immobilized nature of the anions, poor ion-pair dissociation, and the slower time scale diffusion in a polymer matrix compared to liquid electrolytes.

In this study, cyclic carbonate-based polymer electrolytes were synthesized to mimic the beneficial properties of conventional carbonate-based liquid electrolytes, such as high level of ion dissociation and solid electrolyte interphase (SEI) formation. A series of copolymers were synthesized varying the structure and composition of the anionic monomer and polar cyclic carbonate containing monomer. The tertiary hydrogen on these carbonate monomers can act as a crosslinking point in free radical polymerizations or UV curing processes to provide robust mechanical properties to the SPEs at elevated temperatures. Although the inherent conductivities of the single-ion SPEs are on the order of 10-7 mS/cm, the addition of plasticizers can improve these conductivities to 0.1 mS/cm.
The Electrical Double Layer in Battery Electrolytes
Authors: Shi Feifei
Published: July 2022

The electrical double layer (EDL) is the interfacial layer that exists at the electrode/electrolyte solution boundary, which governs adsorption phenomena and electron transfer during the electrochemical reaction. A lot of crucial heterogeneous phenomena (e.g., corrosion, electrostatic adsorption, intercalation, electrocatalysis) are controlled by the characteristics of the EDL, which makes it the holy grail in the electrochemistry system. While simulations have provided some insights, direct experimental observation of the EDL structure has rarely been made. Currently, the main challenge is to develop a new experiment and analysis method that is appropriate to directly probe the EDL structure. In this talk, I will revisit the typical methods which are widely used for EDL measurement, comparing, and discussing their cons and pros. Lastly, I’ll focus on the new method to measure EDL in battery electrolyte systems.
Extending Electrochemical Stability Window As a Result of Carbonate-Ketone Side Chain Modified Polyethylene Glycol Electrolytes for Lithium Batteries
Authors: Raj Ashish , Grignard Bruno , Detrembleur Christophe , Gohy Jean Francois
Published: July 2022

Solid state batteries are of wide interest owing to their high energy density and safety. Their stability with high voltage cathodes is not new to the researchers and are advantageous in various terms. Although ethylene oxide side chains being one of the most studied system also suffers from serious setback with its prime backbone. Here in our work, we studied the effect of terminal group of linear and tri-arm polyethylene glycol (PEG-OH) by converting it to carbonate-ketone (Carb-ket) from hydroxyl. We synthesized the polyethylene carb-ket (TPEG-carb-ket) terminal by ring opening reaction. The carb-ket functionality at the chain end not only increase the electrochemical stability window > 4.47 V but also limits the parasitic reactions with lithium metal stabilising SEI at the interface. The latter demonstrated the superior galvanostatic charge-discharge of LiFePO4 using as synthesized electrolyte loaded with LiTFSI salts as compare to similar chain length PEG-OH. This make the vast impact on controlling the undesired decomposed products at the interface to facilitate the high coulombic efficiency and capacity retention The TPEG-carb-ket also hinted at stable interface with lithium as a result of stripping and plating for more than 1200 h. These experiment results provide important insights backed by AIMD simulations in comparison with hydroxyl terminal system. Our study would aide with the major step on improving the higher voltage cathode with superior performance in the lithium batteries.
Current-Corrected Cycling for True Electrode Performance Measurement
Authors: Yan Zilai , Scott Ben , Glazier Stephen , Obrovac Mark
Published: July 2022

In battery research, galvanostatic cycling is the most widely used method to evaluate electrode performance.1 By applying pre-set current throughout the test, this method often fails to accurately reflect electrode performance at the designed cycling rate (particularly for high-rate cycling) because the actual capacity can be considerably affected by polarization and electrode degradation.2 To address this issue, a current-corrected galvanostatic cycling (CCGC) method is proposed, in which the current is actively adjusted during cycling based on the measured capacity of previous cycles.3 Compared to the traditional galvanostatic cycling (TGC) method, which may result in cycling rates that are hundreds of times faster than the designed rate, the proposed cycling strategy can effectively measure rate-dependent electrode performance precisely at designated rates.

As shown in Figure 1, graphite electrodes were cycled in half cells at different rates ranging from C/20 to 5C using TGC and CCGC methods. For TGC, the capacity decreases quickly at rates higher than C/5 and becomes negligeable when the rate is ≥ 2C. This is because the actual cycling rates are much higher than the designed rates when the capacity becomes lower due to polarization, as shown in Figure 1(b). For instance, at a designed 5C rate, the observed actual cycling rate for TGC is 1200 C – 3600 C, about 500 times higher than the designed rate. In addition to the low capacities at high rates, at C/2 the capacity is not stable, due to the increasing overpotential, which causes staging plateaus to be truncated by the lower potential cutoff.

References

J. Liu et al., Nat. Energy, 4, 180–186 (2019).

C. Heubner, M. Schneider, and A. Michaelis, Adv. Energy Mater., 10, 1902523 (2020).

Z. Yan, B. Scott, S. L. Glazier, and M. N. Obrovac, Batter. Supercaps (2021) doi: 10.1002/batt.202100345.

Figure 1 (a) Lithiation capacity and (b) the actual cycling rate of graphite electrodes cycled at different rates using CCGC and TGC. Reproduced with permission from ref 3. Copyright 2021 Wiley-VCH GmbH.

Figure 1
Reducing Intrinsic Drawbacks of Ni-Rich NMC811 Cathode By Blending with LMO Cathode in 18650 Lithium-Ion Batteries
Authors: Nanthamitr Puttida , Tomon Chanikarn , Sawangphruk Montree
Published: July 2022

The commercial NMC811 cathode can provide high specific capacity and energy density but it has poor capacity retention leading short cycle life and severe safety hazards because their instability of layer structure. Whist, spinel LMO cathode has high stability with great capacity retention but low specific capacity and energy density. In this work, blended NMC811/LMO cathode in the ratio of 2:1 can increase the capacity around 69% when compared with pristine LMO. Moreover, the blended NMC811/LMO in the ration of 2:1 can provide the high-capacity retention more than 80% in 450 cycles that higher than pristine NMC811 around 40% and give the highest energy density equal to 189.3 Whkg-1. Thus, the blended NMC811/LMO can solve intrinsic drawbacks of these two cathode materials (NMC811 and LMO) and can be used to further develop the 18650 batteries in the industrial level to be more efficient.
Garnet-Based Composite Cathodes for All-Solid-State Lithium Batteries
Authors: Ihrig Martin , Laptev Alexander M , Finsterbusch Martin , Fattakhova-Rohlfing Dina , Guillon Olivier , Ye Ruijie
Published: July 2022

Garnet-based all-solid-state lithium batteries (ASSLB) provide high intrinsic safety, extended operational temperature range, and high energy density. As the first two are intrinsic to the materials system, one prerequisite to obtain high energy densities with such ASSLBs is the manufacturing of composite cathodes. Preferably, cathode active material (CAM) and electrolyte should form an intertwined 3D-network with an intimate extended contact between two phases. The interface between the CAM and the electrolyte should feature high total surface area with a low impedance to enable an efficient charge transfer and transport and minimize the resistance losses in a battery.

Composite solid cathode microstructures can be formed via a co-sintering of solid electrolyte and CAM powders. However, many CAMs such as Li[Ni1-x-yCoxMny]O2 (NMC), Li[Ni1-x-yCoxAly]O2 (NCA) or Li2NiMn3O8 (LMO) cannot withstand sintering temperatures required, for oxide class solid electrolytes as Li7La3Zr2O12 (LLZ) or Li1+xAlxTi2-x(PO4)3, to obtain sintered composite cathodes. Furthermore, the thermodynamic stability of CAMs significantly decreases in the presence of solid electrolytes. Still, several groups have demonstrated that thermodynamic limitations can be significantly lessened via a kinetic control of the process such as reduction of reaction times and a careful control of powder morphology during ceramic sintering process.

Following this work, we demonstrate that Field Assisted Sintering Technique / Spark Plasma Sintering (FAST/SPS) enables fabrication of different functional solid-state battery components within minutes such as dense LLZ separator layers with a high ionic conductivity, thick LiCoCO2 (LCO)/LLZ composite cathodes without any interfacial reactions, and integrated cathode half-cells consisting of a composite cathode and a LLZ separator layer at temperatures as low as 675 °C. . The analysis of these composite cathodes revealed well sintered pure phases and a homogenous distribution of cubic LLZ and cathode active material. Electrochemical tests showed promising electronic and ionic conductivity (0.4 mS cm-1) values and an increased capacity (4 mA cm-2) compared to cathodes with pure active material.

The structural analysis after the electrochemical characterization shows the mechanical integrity of the LLZ/LCO interface, which means that a mechanically stable rigid LLZ/LCO interface can be obtained.

Such a mechanically stable LLZ/LCO cathode allows to analyze possible electrochemistry induced degradation, which is suggested by theoretical work but lacks experimental validation. A detailed analysis of the LLZ/LCO interface by SEM, TEM, Raman, and XRD provide insights into the processes occurring during electrochemical cycling. The findings can pave the way to increase the cycling stability of ceramic all-solid-state batteries via interface optimization

Figure 1
Utilizing Triethyl Phosphate to Increase the Solubility of Lithium Nitrate for Improved Silicon Anode Performance
Authors: Rynearson Leah L , Rynearson Leah
Published: July 2022

An electrolyte consisting of lithium nitrate (LiNO3) and lithium difluoro(oxalto)borate (LiDFOB) in ethylene carbonate (EC), ethylmethyl carbonate (EMC), and triethyl phosphate (TEP) was used to improve the long-term cycling stability of silicon anodes. TEP was selected for its ability to dissolve LiNO3 in carbonates to a concentration of ~0.2 M. The large amount of LiNO3 combined with the LiDFOB salt led to a capacity retention of 87.1% after one hundred cycles due to the formation of a stable solid electrolyte interphase (SEI). Ex-situ surface analysis revealed that the SEI consists of oxalates, lithium alkyl carbonates, borates, and nitrate decomposition products. By selecting two components that preferentially reduce before the rest (LiNO3 and LiDFOB), the SEI formed was able to prevent significant solvent decomposition and allow for improved electrochemical cycling in pure silicon anodes.