bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-Healing Commodity Polymer Electrolytes for Reliable Li Metal Batteries
Authors: Lorandi Francesca , Liu Tong , Dadashi-Silab Sajjad , Zhao Yuqi , Yin Rongguan , Whitacre Jay , Matyjaszewski Krzysztof
Published: July 2021

As countries worldwide pledge to decarbonize their economy, the global demand for batteries is rapidly increasing, urging the development of high-specific-energy (> 500 Wh/kg at cell level) and low-cost (< 100$/kWh at pack level) batteries.1 The safety and durability of these devices are of primary importance. Polymer electrolytes are safer than traditional liquid electrolytes, and further benefit from highly tunable structures.2 Thus, polymers can be designed to achieve desired properties, including the ability of self-healing from damages, which can greatly extend battery lifetime. While the synthesis of self-healing polymers often requires specifically designed monomers or other polymerization components, it was recently shown that commodity copolymers, based on methyl methacrylate (MMA) and n-butyl acrylate (nBA) or their derivatives, display self-healing behavior.3 The autonomous self-repair of these copolymers with certain compositions is governed by interchain van der Waals forces.

Herein, this finding was exploited to prepare self-healing polymer electrolytes that ensured long-term performance of high-energy Li metal batteries. The electrolytes were based on polyethylene oxide (PEO), P(MMA-co-nBA) copolymers and Li bis(trifluoromethanesulfonyl)imide (TFSI) salt. Various structures and compositions were explored, including polymer blends and block copolymers made by atom transfer radical polymerization (ATRP) using a functionalized PEO-macroinitiator (Figure 1). The effect of polymer morphology, architecture, weight fraction of PEO and LiTFSI on electrolyte conductivity, thermal and electrochemical stability, Li transference number, mechanical strength and self-healing ability was analyzed.

By recovering ionic conductivity and mechanical strength upon cracks, self-healing electrolytes can suppress the growth of dendrites that hinders the utilization of Li metal anodes.4 Moreover, the viscoelastic nature of these polymers contribute to the creation of conformal interfaces on Li metal.2 Therefore, the optimized commodity self-healing polymer electrolytes were tested in Li metal batteries, demonstrating the ability of the electrolytes to enable long-term stable cycling. In addition, tests were conducted to prove the self-repair of the electrolyte upon damaging the device.

References:

1 J. Liu, Z. Bao, Y. Cui, E. J. Dufek, J. B. Goodenough, P. Khalifah, Q. Li, B. Y. Liaw, P. Liu, A. Manthiram, Y. S. Meng, V. R. Subramanian, M. F. Toney, V. V. Viswanathan, M. S. Whittingham, J. Xiao, W. Xu, J. Yang, X.-Q. Yang, J.-G. Zhang, Nat. Energy 2019, 4, 180-186.

2 J. Lopez, D. G. Mackanik, Y. Cui, Z. Bao, Nat. Rev. Mater. 2019, 4, 312-330.

3 M. W. Urban, D. Davydovich, Y. Yang, T. Demir, Y. Zhang, L. Casabianca, Science 2018, 362, 220-225.

4 L. Zhao, N. R. Sottos, Adv. Energy Mater. 2020, 2003139.

Figure 1: structure of a self-healing copolymer electrolyte and illustration of Li dendrite suppression.

Figure 1
Multiscale Modelling of Nanostructured Foil Anode for Next Generation Batteries
Authors: Srikanda Prabanna Balan Kirutiga , Shah Krishna , Yu Jiwon , Heligman Brian Theodore , Manthiram Arumugam , Subramanian Venkat R. , Hwang Gyeong S. , Muthuraman Kumar
Published: July 2021

Interdigitated Eutectic Alloy anode (IdEA) is a promising new candidate for next generation batteries due to its high specific capacity (250-300 mAh/g) [1]. Multiscale modeling approaches are essential to study such new battery chemistries. They help examine the underlying electrochemical properties and phase transitions, including the transport, kinetics and reaction schemes. In this study, we present a multiscale modeling analysis, of a Li-ion cell with a ZTB (Zn-Sn-Bi) IdEA, consisting of DFT simulation and continuum level electrochemical engineering modeling aided by experimental measurements. The DFT simulation is conducted to obtain diffusivity of the alloy anode undergoing phase changes. The electrochemical engineering model is developed based on a 1D reaction-diffusion equation and it models the kinetics and transport in the alloy anode-based battery system. Using this 1D model, a moving phase front has been observed when the eutectic alloy undergoes phase transition during charge/discharge. The cell level voltage response obtained from this model is validated with the experimental data. The practical relevance can be maximized by formulating a techno-economic model.

Heligman, B.T., Kreder III, K.J. and Manthiram, A., 2019. Zn-Sn interdigitated eutectic alloy anodes with high volumetric capacity for lithium-ion batteries. Joule, 3(4), pp.1051-1063.
Ultrastable Sn-Based Anode Enabled By a Self-Nanocrystallization Strategy for Sodium-Ion Batteries
Authors: He Wei , Zhou Yue
Published: July 2021

Sodium ion batteries (SIBs) are considered as an alternative of lithium-ion batteries (LIBs) in large scale energy storage due to the rich resource and low cost of sodium. However, compared with lithium ion (Li+), sodium ion (Na+) has a larger ionic radius and sluggish diffusion kinetics, hindering the further practical applications of SIBs. Hence, considerable efforts have been devoted to develop high-performance anode materials with low cost, high capacity, and long cycle life. Conversion/alloying type anodes have shown great promise for sodium ion batteries (SIBs) owing to their high theoretical capacity. However, the poor structural stability derived from the large volume expansion and short lifetime hinder their further practical applications. Herein, we report a novel anode with SnP2O7 particles homogeneously dispersed in the robust nitrogen-doped carbon matrix by a facile and scalable method. For the first time, we make use of self-nanocrystallization to generate ultrafine SnP2O7 particles, which shorten the diffusion pathway of sodium ions and electrons to promote the reaction kinetics. Ex situ transmission electron microscope (TEM) reveals that the average particle size of SnP2O7 decreases from 66 nm to 20 nm upon cycling. Furthermore, the N-doped carbon matrix forms strong interaction with the self-nanocrystallization ultrafine SnP2O7 particles, leading to a stable nanostructure without any particle aggregation under a long cycle operation. The N-doped carbon matrix and the self-nanocrystallization SnP2O7 particles together bring the SnP2O7@C anode excellent capacitive-energy-storage behavior of 82.4% at a scan rate of 0.6 mV s-1 as revealed by kinetic analysis. Benefiting from these synergistic merits, the SnP2O7@C anode shows a high reversible capacity of 403 mAh g-1 at 200 mA g-1 and outstanding cycling stability of 4000 cycles at 1000 mA g-1 (0.007 % capacity decay per cycle). This work provides new insights on the effective fabrication of high-performance conversion/alloying anode materials for SIBs.

Figure 1
Effects of Silicon Content in Silicon-Graphite Composite Anode on Capacity Degradation
Authors: Sittisomwong Poom , Bai Peng
Published: July 2021

Silicon, with its theoretical capacity of 4200 mAh g-1,[1] has been exploited as a capacity-booster for mature graphite anodes. However, silicon is prone to fast degradation due to significant volume expansion, which may undermine the intrinsic stability of the graphite, resulting in shorter cycle life. The trade-off between higher capacity and shorter cycle life is therefore worth optimizing. This study investigates the effects of silicon content on the cycling performance of silicon-graphite composite anodes. The composite electrodes were synthesized by mixing both materials at various weight ratios, along with carbon black and polyacrylic acid solution, and coated on a copper foil. A mixture of 1 M of LiPF6 in EC: DMC, 1:1, v/v, and Fluoroethylene carbonate (FEC) was used as the electrolyte. The samples consist of electrodes with silicon content from 8% to 40%. Galvanostatic test was done at various C-rates to determine the specific capacity at each cycle, and the correlation between the voltage and the capacity during the test was used to create differential capacitance curves. Electron microscopy and energy-dispersive X-ray spectroscopy were used to study morphology and to detect agglomeration of silicon particles. The results show that the initial capacity and the capacity retention of each sample indeed depend on the silicon content. As expected, higher silicon contents yield higher initial specific capacities but cause faster degradation. However, the trends do not continue beyond 32% of Si content. This suggests that there is a limit for silicon to enhance the initial specific capacity at a fixed C-rate. Differential capacitance curves show the gradual disappearance of silicon peaks, e.g., a peak at 0.45 V, which indicates that the primary cause of the capacity loss is the degradation of silicon material. Elemental analysis shows the high content of silicon content can promote particle agglomeration. Future tasks will include establishing the relationship between the silicon content and quantifying the amount of silicon agglomeration using X-ray spectroscopy. The results from this study can be used to assess an appropriate amount of silicon in anode material.

References

[1] Gu, M., He, Y., Zheng, J., & Wang, C. (2015). Nano Energy,
17, 366-383.

Figure 1
The Mechanical and Electrochemical Behaviour of Red Phosphorus in Lithium, Sodium and Potassium-Ion Batteries
Authors: Capone Isaac , Pasta Mauro
Published: July 2021

Red phosphorus (RP) is a promising anode material for alkali-ion batteries due to its ability to alloy at low potentials with Li, Na and K to form the phases Li3P, Na3P and KP, delivering a high theoretical capacity of 2596, 2596 and 865 mAh g-1, respectively. However, its main disadvantage is its very large volumetric expansion during the alloying reaction (168% with Li, 331% with Na and 161% with K) that can cause, loss of electrical contact, low Coulombic efficiency, and ultimately poor cycle life. Other alloying materials such as silicon have shown to suffer from the fracturing of the particles during the reaction with lithium. In this work, we discuss if this is the case for phosphorus too [1]. Through comprehensive electrochemo-mechanical characterisation and modelling of the cycling stresses, we show that RP can be cycled at high current densities without fracture. A model that can simulate the volume expansion of RP during the reaction with the alkali metals Li, Na and K, as well as the generation and evolution of stresses on the particles is developed. Its use required the implementation of the elastic, plastic and fracture properties of RP that are measured by novel application of in-situ nanoindentation and powder compression. The validity of the model is also tested through in-situ TEM observation with extreme conditions (anisotropic ion diffusion and high current density) where no catastrophic failure was observed. The mechanical and the electrochemical characterisation, together with the model developed in this work allows for predictions to be made for the application of RP in alkali-ion batteries.

REFERENCE

[1] Capone et al., Matter 2020 3 (6), 2012-2028
CO2-Derived Hierarchical Porous Carbon Electrode and Interlayer Doped with Nitrogen for Lithium-Sulfur Battery
Authors: Park Jae Hyun , Gim Hyeonseo , Choi Won Yeong , Lee Heecheon , Sang Yeon Lee , Yang Jeongwoo , Lee Jae W
Published: July 2021

Shuttle phenomena of lithium polysulfides (LiPSs) in lithium sulfur (Li-S) batteries is a serious obstacle to commercialization of Li-S battery. Various studies are being conducted to mitigate the shuttle effect, but among them, the approach using an interlayer has been introduced. This study proposes a hierarchical carbon material for both carbon cathode composite and interlayer synthesized from gaseous carbon dioxide. The highly porous carbon material used as a cathode enables a homogeneous distribution of active materials such as sulfur without agglomeration and allows rapid diffusion of ions. In addition, the interlayer made in this study is 30wt% lighter than the existing fiber-type paper layer based on its high porosity and at the same time has a very high 15.5% nitrogen atoms. Excess N atoms including pyridinic-N and pyrrolic-N contained in the interlayer prevent diffusion of LiPSs to the counter electrode through strong chemical bonds with LiPSs, and also greatly improve conductivity, minimizing resistance related to charge transfer. As a result, the cells assembled with them maintain a capacity of 700 mAh g−1 after 500 cycles at 0.5 C. In addition, it can exhibit a capacity of 697 mAh g−1 even at a high current density of 7.0 C.
Li-Ion Conductive Hybrid Solid Electrolytes Based on Li6PS5cl and Self-Aligned Polymer for All-Solid-State Lithium Batteries
Authors: Lee Si-Eun , Hong Seung-Bo , Lee Young-Jun , Kim Dong-Won
Published: July 2021

Lithium-ion batteries (LIBs) are promising energy storage devices because of their high energy density and long cycle life. However, the liquid electrolytes used in LIBs still cause the safety concerns due to flammability and leakage problem. Therefore, all-solid-state lithium batteries (ASSLBs) have attracted great attention owing to their enhanced safety and wide operating temperature range. Among the various solid electrolytes, sulfide-based solid electrolytes have been actively studied due to their high ionic conductivities. However, they suffer from the lack of flexibility to make thin sheet. Because of these concerns, the hybrid electrolytes composed of sulfide and polymer can be a good strategy for manufacturing thin sheet. In our study, we employed self-aligned polymer with high thermal stability to make the hybrid solid electrolyte based on highly conductive Li6PS5Cl in the form of thin sheet. Their electrochemical properties are characterized and they are applied to the Li/LiNixCoyMn1-x-yO2 cells. Based on our results, the self-aligned polymer is proposed as a promising filler for preparing the hybrid solid electrolyte in a form of free-standing thin sheet for applications in all-solid-state lithium batteries.
Cerium Oxide Nanostructures with Controllable Reactivity for Sensing and Environmental Applications
Authors: Othman Ali , Andreescu Emanuela
Published: July 2021

Ceria (CeO2) nanostructures are used in a broad range of applications in catalysis, biomedicine, sensing and in the semiconducting industry. Their surface reactivity, catalytic, mechanical and spectral properties provide unique features that have enabled many applications. Examples of emerging applications include their use as therapeutic antioxidants to modulate oxidative stress in biological systems, as redox active probes to design bioanalytical assays. Moreover, ceria nanostructures are widely as a polishing abrasive in the chemical mechanical planarization process (CMP) in the manufacturing of printed circuits by the semiconductor industry. To obtain specific surface properties, as well to improve their redox reactivity, synthesis approaches including surface modification and coating, doping and support functionalization could be used. Studies were designed to investigate the effect of the particle size, dopant and surface coating on the redox reactivity, adsorption/desorption/ligand exchange processes and the optical and catalytic properties of the nanostructures that will be used for the fabrication of CeO2 based sensing platforms and separation devices.

This work provides a critical evaluation of the redox properties of CeO2 nanostructures that can enable rational design and selection of suitable candidates for sensing and environmental applications based on their reactivity and surface properties.
On the Parameters Affecting Calcium Plating and Stripping from Organic Electrolytes – Cases of Electrolyte Optimization
Authors: Forero-Saboya Juan , Ponrouch Alexandre
Published: July 2021

Among the different next-generation battery technologies, the ones based on divalent cations have recently gained particular attention due to their higher raw material availability and potentially higher energy density when compared with Li-ion. Such is the case of calcium, being the 5th most abundant element in the earth crust and having a standard redox potential only 170 mV above metallic lithium. However, the development of a secondary calcium-metal battery had been hampered by the lack of organic electrolytes allowing for reversible plating and stripping, which was only recently reported by our group and others employing different electrolyte formulations.

The different electrolyte components – salt(s), solvent(s) and additive(s) – are expected to play a significant role in the operation of a calcium-metal battery. Here we will show how the solvation structure of the cation evolves in relation to the solvent employed and the concentration of the salt. Combining conductivity measurements with Raman spectroscopy data, a high tendency to form contact ion pairs is evidenced, which significantly affects the mobility of the ions in the liquid media. The use of different anions and their bonding strength with Ca2+ in solution will be discussed. Combined, the anion and solvent characteristics dictate the solvation of the cation, which in turn can affect the Ca plating and stripping kinetics.

Additionally, the presence of electrolyte contaminants will be explored. The crucial yet very challenging drying of electrolyte containing Ca(BF4)2 in carbonate solvents will be presented. The difficulties to obtain anhydrous and contaminant free solutions from commercially available salts will be discussed and two alternative routes for anhydrous synthesis of the target salt will be presented.
(Invited) Water-Mediated Intercalation Mechanisms in Transition Metal Oxides
Authors: Augustyn Veronica
Published: July 2021

Understanding host-guest interactions of layered inorganic solids ushered in the modern era of portable electronics powered by lithium-ion batteries. Future improvements in the power capability of these devices, and their potential use in emerging technologies such as water treatment, critical element recovery, and ion-based electronics, depend on the development and understanding of new ion insertion hosts with fast insertion kinetics. One avenue is via tuning the interlayer environment of a layered material, since many are flexible hosts whose interlayers can accommodate not just electrolyte ions but also solvents, organic molecules, polymers, and organometallics. In this presentation, I will present our group’s research in the mechanistic understanding of water-mediated ion intercalation in transition metal oxides. I will discuss the role of ordered and confined water networks in transition metal oxide hydrates, the design of metastable hydrated oxides via displacement of interlayer ions by water, and the role of disordered and confined water networks in electrochemical capacitor materials. The fundamental understanding of these materials, which blur the distinction between solid and liquid, paves the way for electrochemical ion insertion applications with high power capability.
Solid Electrolyte Interphase on Li/Na Anodes in Contact with Liquid Electrolytes
Authors: Popovic Jelena , Lim Kyungmi , Drvaric-Talijan Sara , Nojabaee Maryam , Maier Joachim
Published: July 2021

Electrolyte consumption and continuous solid electrolyte interphase (SEI) growth are some of the crucial issues preventing the commercialization of battery systems depending on implementation of Li/Na metal anodes.1 In this work, recent study of SEI growth on Li metal in contact with glyme-based liquid/solid electrolyte under galvanostatic and OCV conditions by electrochemical impedance spectroscopy (EIS), ex situ X-ray photoelectron spectroscopy (XPS), and focused ion beam scanning electron microscopy (FIB-SEM) is presented.2,3 Under OCV conditions, reaction-controlled mechanism is substituted by diffusion-controlled mechanism at longer growth times. Upon galvanostatic cycling, both the SEI thickness and its room temperature ionic conductivity increase. Additionally, the transport properties of SEI are strongly influenced by the type of lithium salt and the concentration used. In the last part, a comparison of SEI growth in Li vs. Na cells in contact with glymes, carbonates, and water-containing electrolytes is given.4

Zhang, Zuo, Popovic, Lim, Yin, Maier, Guo, Towards better Li metal anodes: Challenges and strategies, Materials Today, 33, 56 (2020)

Nojabaee, Popovic, Maier, Glyme-based liquid-solid electrolytes for lithium metal batteries, J. Mater. Chem. A, 7, 13331 (2019)

Nojabaee, Küster, Starke, Popovic, Maier, Solid electrolyte interphase evolution on lithium metal in contact with glyme-based electrolytes, Small, 16(23), 2000756 (2020)

Lim, Popovic, Maier, in preparation
Efficient Lithium Metal Cycling at a Wide Range of Pressures from an Anion-Derived Solid-Electrolyte Interphase Framework
Authors: WANG Hansen , Cui Yi
Published: July 2021

Novel electrolytes have been developed to improve the cyclability of lithium (Li) metal anodes, yet their working mechanisms remain unclear. The dependence of the performance on the operational pressure can provide valuable insights on the Li plating mechanisms in different electrolytes. Here, we study Li cycling performance evolution against pressure in 1 M LiFSI/fluorinated 1,4-dimethoxylbutane (FDMB) electrolyte, one of the highest-performing electrolytes for Li metal to date. We show that it enables excellent Coulombic efficiency (CE) in a pouch cell format under a wide range of initial pressures (30-600 psi). We discover that this is due to a completely different Li plating mode with superior deposition morphologies compared to that in a conventional carbonate electrolyte, which exhibits increasing cycle stability with increased pressure. We show that this is enabled by the properties of an anion-derived residual solid-electrolyte interphase (rSEI) framework on the electrode surface, an undercharacterized structure with profound implications for Li metal cycling. The plating morphology enabled by this anion-derived rSEI chemistry is likely the key to a prolonged cycle life in high performance electrolytes for Li metal.
Study of Solid State Lithium Batteries with a Ceramic Electrolyte
Authors: Dussart Thibaut , Stevens Philippe , Toussaint Gwenaelle , Laberty-Robert Christel
Published: July 2021

Solid state lithium batteries are considered as the next generation of batteries due to its potential higher energy density and better safety compared to Li-ion technology[1]. Oxides, sulfides, polymers and polymer/ceramic hybrid materials can be used as lithium ion conducting solid electrolytes, some of which have very good ionic conductivities (up to 10-3 S.cm-1 at 25°C) and good electrochemical stability[2,3].

Li1,3Al0,3Ti1,7(PO4)3 (LATP) is a potential candidate as a solid electrolyte with an ionic conductivity of 1.10-4 S.cm-1 at 25°C. It is stable up to 5V vs Li/Li+ but it is instable in contact with lithium due to the reduction of Ti4+ in Ti3+ [4]. A thin protective layer of a stable lithium ion conducting material is deposited to avoid contact between LATP and Li metal[5]. The LATP solid electrolyte has been synthesized via solid state synthesis and LATP particles exhibit a cubic morphology.

Aluminum doped Li7La3Z2O12 (LLZO), another good candidate for solid electrolyte, displays a high ionic conductivity >10-4 S.cm-1 [6] and an good stability in contact with lithium metal. LLZO synthesized by the Pechini route exhibit a cubic phase with no impurity phase.

The main challenge is to control this interphase in order to decrease the interfacial resistance. Different strategies are employed to deposit the lithium such as electrochemical deposition and vapor deposition. Full cells are assembled using different positive electrode compositions and characterized in order overcome the technological barriers related to this technology.

[1]T. Placke, R. Kloepsch, S. Dühnen, M. Winter, Lithium ion, lithium metal, and alternative rechargeable battery technologies: the odyssey for high energy density, J. Solid State Electrochem. 21 (2017) 1939–1964. doi:10.1007/s10008-017-3610-7.

[2]J. Janek, W.G. Zeier, A solid future for battery development, Nat. Energy. 1 (2016) 1–4. doi:10.1038/nenergy.2016.141.

[3]Y. Zhu, X. He, Y. Mo, Origin of Outstanding Stability in the Lithium Solid Electrolyte Materials: Insights from Thermodynamic Analyses Based on First-Principles Calculations, ACS Appl. Mater. Interfaces. 7 (2015) 23685–23693. doi:10.1021/acsami.5b07517.

[4]P. Hartmann, T. Leichtweiss, M.R. Busche, M. Schneider, M. Reich, J. Sann, P. Adelhelm, J. Janek, Degradation of NASICON-type materials in contact with lithium metal: Formation of mixed conducting interphases (MCI) on solid electrolytes, J. Phys. Chem. C. 117 (2013) 21064–21074. doi:10.1021/jp4051275.

[5]H.S. Kim, Y. Oh, K.H. Kang, J.H. Kim, J. Kim, C.S. Yoon, Characterization of Sputter-Deposited LiCoO2 Thin Film Grown on NASICON-type Electrolyte for Application in All-Solid-State Rechargeable Lithium Battery, ACS Appl. Mater. Interfaces. 9 (2017) 16063–16070. doi:10.1021/acsami.6b15305.

[6]R. Murugan, V. Thangadurai, W. Weppner, Fast lithium ion conduction in garnet-type Li7La3Zr2O12, Angew. Chemie - Int. Ed. 46 (2007) 7778–7781. doi:10.1002/anie.200701144.

Figure 1
(Invited) Molecular Modeling of Lithium and Zinc Electrolytes
Authors: Borodin Oleg , Pollard Travis , Vatamanu Jenel , Schroeder Marshall , Ma Lin , Wang Chunsheng , Xu Kang
Published: July 2021

In this presentation I will update on the recent progress towards obtaining fundamental understanding and improving three classes of electrolytes: 1) aqueous and hybrid electrolytes for lithium ion batteries including superconcentrated electrolytes; 2) non-aqueous electrolytes and their interaction with the electrodes for high energy density lithium ion batteries; 3) electrolytes for zinc metal batteries.

Accurate molecular dynamics (MD) simulations of these electrolytes using many-body polarizable force field will be used to establish a correlation between the ion transport mechanisms, electrolyte structure and transference number. Reactive modeling will focus on the competitive solvent and salt reduction at the passivated electrochemical interfaces using Born Oppenheimer Molecular Dynamics (BOMD) simulations using DFT functionals. These BOMD simulations included critical factors needed to realistically represent electrolyte reactivity at electrodes such as explicit description of the substrate – electrolyte interactions; accurate representation of electrolyte structure, ion pairing and aggregation near an electrode; and collection of sufficient statistics from multiple unique simulations that were initiated with differing initial configurations. Electrolyte reduction at the passivated interfaces from these simulations will be contrasted with other solvents ranging from ethers with mixed salts or carbonates and results from the representative quantum chemistry (QC) calculations performed on the small model electrolyte clusters to estimate oxidation and reduction.
Dimensional Changes during Cycling
Authors: Yi Tanghong
Published: July 2021

Lithium-ion batteries experience dimensional changes during cycling due to several mechanisms. Traditional anode and cathode active materials such as lithium cobalt oxide and graphite expand and contract during lithiation and delithiation. Addition of silicon to the anode can results in even greater volumetric changes. Batteries containing lithium metal anodes or anode free designs based on lithium metal must also accommodate significant expansion and contraction as the lithium plates and strips. In this presentation, we will demonstrate the use of high throughput in situ measurements of these dimensional changes for a variety of materials. Data can be used to better design electrodes to minimize volumetric changes with cycling.
Anionic Redox Investigation of Na2Mn3O7 Electrode Material for Sodium-Ion Batteries
Authors: Hakim Charifa , Ma Le anh , Younesi Reza , Brandell Daniel , Edstrom Kristina , Saadoune Ismael
Published: July 2021

NaxMeyOz oxides have attracted wide attention as promising cathode materials for sodium-ion batteries because of their potential high capacity and rate capability (1). The stable cycling performance, usually obtained within a low voltage range, drastically decrease when cycled at high voltage range despite the large initial charge capacity. Thus, it has been suggested that besides storing charge on the transition metal ions, oxygen ions can also participate in the charge compensation mechanisms at high voltage which induces an oxygen loss from the lattice when charging which is the reason behind the poor cycling stability (2).

In this work, the aim is to investigate the anionic redox reactions of Na2Mn3O7 cathode material, within the voltage window of 1.5 – 4.5 V using combined soft X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) which allow us to study the electronic structure of this material.

Keywords: Energy, Storage, Sodium-ion, Cathode, layered oxide, anionic redox, oxygen activity.

References:

Delmas, C., Braconnier, J.-J., Fouassier, C. & Hagenmuller, P. Electrochemical intercalation of sodium in NaxCoO2 bronzes. Solid State Ionics. 3/4, 165–169 (1981)

Assat, G. & Tarascon, J. Fundamental understanding and practical challenges of anionic redox activity in Li-ion batteries. Energy
3, 373–386 (2018).

Acknowledgements: The Swedish Research Council (VR) financially supported this work via project 2017-05466
Novel Quasi-Liquid K-Na Alloy as a Dendrite-Free Anode for Potassium Metal Batteries
Authors: Tai Zhixin , Lu Ziyu , Liu Lifeng
Published: July 2021

Rechargeable potassium metal batteries are promising energy storage devices with potentially high energy density and markedly low cost. However, there are key challenges to eliminate dendrite growth and achieve a stable electrode/electrolyte interface. While liquid potassium-sodium alloy (KNA) has recently been demonstrated to be able to address the dendrite growth issue, it has poor mechanical processability due to its high degree of fluidity, which is difficult to be processed for use in practical potassium batteries. In this presentation, we report a novel “quasi-liquid” KNA comprising only 3.5 wt% Na, which exhibits superior electrochemical performance able to be repeatedly plated and stripped on the copper substrate at 0.5 mA cm-2 up to 220 cycles with a high Coulombic efficiency of above 89%. Moreover, an unusual metastable KNa2 phase is captured during the K-Na plating by in-situ X-ray diffractometry, which may assist in the nucleation of K and Na continually during plating, helping to suppress the formation of dendrites. The “quasi-liquid” KNA-3.5 anode demonstrates markedly enhanced electrochemical performance in a full cell when pairing with Prussian blue analogues or sodium rhodizonate dibasic as the cathode material, compared to the pristine potassium anode. Importantly, unlike the liquid KNA reported before, the “quasi-liquid” KNA-3.5 exhibits good processability and can be readily shaped into sheet electrodes, showing substantial promise as a dendrite-free anode in rechargeable potassium metal batteries.
Peering into Batteries: Electrochemical Insight through in Situ and Operando Methods over Multiple Length Scales
Authors: Li Wenzao , Lutz Diana , Wang Lei , Takeuchi Kenneth J. , Marschilok Amy C. , Takeuchi Esther S.
Published: July 2021

In order to overcome the limitations of static and destructive characterizations of Li-ion battery materials and components, comprehensive investigation peering into batteries over various length and time scales is essential. In this regard, emerging in situ and operando characterization methodologies focusing on multiple size domains become a powerful approach to resolve current challenges and navigate future directions. This perspective provides a series of illustrative examples of in situ and operando characterizations over atomic, crystallite/particle, electrode, and battery system length scales with a focus on two electrode material classes: insertion and conversion materials. The operating principles, features, analysis methods, and information gained from each characterization method are discussed. Herein, we present the necessity and opportunity for in situ and operando characterization of electrochemical energy storage materials and systems. Further, we suggest future directions to gain the insight needed to tackle currently intractable issues on Li-ion battery application, failure, and emerging design concepts.
(Invited) Highly Stable Nanocarbon Catalysts for Reversible Energy Storage and Conversion Via Oxygen Electrocatalysis
Authors: Wu Gang
Published: July 2021

Energy conversion and storage via direct electrochemical oxidation and reduction processes, such as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), can provide a clean, efficient, and economically viable means of meeting this sustainability challenge, by allowing stored renewable energy to be reliably delivered where and when it is needed. During the development of the highly demanded nonprecious metal catalysts to replace precious metals for these applications, carbon catalysts have many advantages over metal oxides, including excellent electrical conductivity, high surface area, and easy functionalization. However, most carbon-based catalysts suffer from poor activity and stability for the more challenging OER under a highly oxidative conditions. This represents one of grand challenges in energy conversion research societies.

For the first time, this work demonstrated that a new class of large-diameter tubular nanocarbon (>500 nm in diameter) catalyst is capable of catalyzing both the ORR and the OER with activity comparable to Pt and exceeding Ir, respectively, for these two reactions. Most importantly, the tube catalyst exhibited good stability upon cycling across a wide potential window (0 to 1.9 V vs RHE) in 0.1 M NaOH electrolyte. The high OER activity was verified using well-designed electrochemical tests, demonstrating that the current generated during the OER arose solely from oxygen evolution, rather than carbon oxidation. This is the first example of such excellent OER activity and durability of a nanostructured carbon-based electrocatalyst across the complete ORR-OER potential window. The newly developed carbon tubes were synthesized via a one-step template-free graphitization process using inexpensive dicyandiamide (DCDA) precursor as carbon/nitrogen source and a ternary FeCoNi alloy as a catalyst. Generation of a mixed metal catalyst, i.e., FeCoNi during the graphitization process is the key factor to yield the largest tube size for maximum electrochemically accessible surface areas, dominant graphitic nitrogen doping, and thicker tube walls, which are associated with the significantly improved activity and durability. The cost effective, easily scalable, single step and environmentally benign synthesis procedure further favors this nanocarbon’s application as a practical bifunctional electrocatalyst for the ORR and OER, with potential to advance the development and commercialization of regenerative fuel cell systems and rechargeable metal-air batteries. The use of nanostructured carbon as bifunctional ORR/OER catalysts will open up new research direction in this field and further advance the role of carbon nanomaterials in oxygen electrocatalysis for energy conversion and storage.
(Invited) Oxygen-Atom Functionalization of Hydrocarbons at Carbon Electrodes
Authors: Manthiram Karthish
Published: July 2021

Oxygen-atom functionalization of chemical intermediates is critical for the production of diverse textiles, plastics, and pharmaceuticals, including epoxides and ketones. The wet chemical and thermochemical routes used today suffer from large carbon dioxide footprints, stoichiometric waste products, and hazardous reagents. We have developed a route whereby water can be used as the oxygen atom source in functionalization reactions of hydrocarbons. At the cathode, hydrogen is selectively generated. Overall, this reaction provides a means by which the oxidizing equivalents can go towards generating a valuable product rather than generating oxygen which is simply vented in a conventional water electrolyzer. We have developed mechanistic understanding of how water is oxidized, providing means by which the selectivity for oxygen-atom functionalization can be rationally improved.
(Invited) Electrospun Carbon Nanofibers for Applications in Fuel Cells and Li-Metal Batteries
Authors: Kim MinJoong , Kang Hyeonmuk , Cho EunAe
Published: July 2021

Carbon nanofibers (CNFs) have been widely utilized in energy conversion and storage devices owing to their excellent electrical conductivities, large surface areas, structural and chemical stabilities. In fuel cells and water electrolyzers, CNFs can be used as a durable support for precious metal nanoparticle catalysts and also as a catalyst itself by being incorporated with nitrogen and transition metals. For lithium (Li) metal anode of rechargeable batteries, CNFs can serve as a interlayer to suppress the formation of Li dendrites.

In this talk, CNFs prepared by electrospinning polyacrylonitrile (PAN) and carbonization are presented for applications in fuel cells and Li-metal batteries. For fuel cell applications, transition metal precursors were added to the electrospinning solution to form the active sites for the oxygen reduction reaction [1]. To make mesoporous CNFs, silica nanoparticles polyvinyl acetate were added to the electrospinning solution [2]. To enhance the Li-ion adsorption on CNFs, metal nanoparticles were added to the spinning solution [3].

[1] M. Kim, D.-H. Nam, H.-Y. Park, C. Kwon, K. Eom, S. Yoo, J. Jang, H.-J. Kim, E.A. Cho, H. Kwon, Journal of Materials Chemistry A, 3, 14284-14290 (2015)

[2] M. J. Kim, J. H. Lim, J. Bak, D. H. Song, S. K. Oh, E. A. Cho "Fe and N Codoped Mesoporous Carbon Nanofiber as a Nonprecious Metal Catalyst for Oxygen Reduction Reaction and a Durable Support for Pt Nanoparticles", ACS Sustainable Chem. Eng., 7(20), 17544-17552 (2019)

[3] H. Kang, MS Thesis, KAIST (2020)

Figure 1
(Invited) A First-Principles Study on the Structure and Properties of Na-Se Alloys for Sodium Ion Battery
Authors: Paek Eunsu , Park Sungwon
Published: July 2021

While selenium (Se) is recognized as a promising cathode material for sodium-ion battery (NIB), fundamental understanding of the Na-Se electrochemical reactions upon sodiation is in its infancy. On the basis of density functional theory and ab initio molecular dynamics simulations, we evaluate single Na incorporation in the crystalline Se and investigate the formation of Na-Se alloys in terms of structural evolution and energetics, along with their mechanical and diffusion properties. Our calculations clearly evidence that the inserted Na atom energetically prefers a heptagonal interstitial site, while cleaving the Se network bonds. We also found that the inserted Na atoms undergo migration with low energy barrier of 0.16 (0.045) eV by jumping to adjacent heptagonal sites through intrachain (interchain) paths. When the Na content is sufficiently high, alloying between Na and Se becomes energetically favorable as evidenced by the negative mixing enthalpy, with the most stable state obtained at 66 at.% of Na. Our calculations also show that the increasing degree of sodiation leads to disintegration of the chain-like bonded Se network into small chain. Lastly, we will discuss the influence of alloy composition on the diffusivity of Na and Se and mechanical properties in amorphous NanSe.
Effects of Graphene Oxide and Reduced Graphene Oxide Interlayer Interactions on the Charge Storage Mechanism
Authors: Ahammad A. J. Saleh , Islam Tamanna , Hasan Md. Mahedi , Sarker Subrata
Published: July 2021

Graphene (GP) has been an object of great interest for researchers ever since its isolation from graphite back in 2004. A great many details about the electronic structure and properties of GP has been extensively studied and the knowledge gained has been utilized in fabricating a wide variety of devices. However, to the best of authors knowledge, there has never been a report studying the interlayer interaction (ILI) properties of graphene oxide (GO)/reduced graphene oxide (rGO) composite. Here, we report fabricating GO_GO, GO_rGO, rGO_rGO, and rGO_GO electrodes through screen printing and study their electronic structure and properties through spectroscopic and electroanalytical methods. The electroanalytical techniques used were cyclic voltammetry, Tafel analysis. electrochemical impedance spectroscopy, chronoamperometry, and galvanostatic charging and discharging (GCD). Standard K3[Fe(CN)6] solution of 1 mM concentration was used in investigating the ILI properties. Furthermore, the electrochemical double layer charge storage (EDLC) mechanism for all the systems were investigated through two electrode symmetrical and asymmetrical setups. Though the research is just in its infancy, analysis of the data obtained so far shows the areal capacitance for the symmetric GO_GO, GO_rGO, rGO_rGO, and rGO_GO systems to be 0.74, 3.24, 0.22, and 0.31 mF/cm2, respectively in 1M KCl aqueous solution. For the asymmetrical system the GO_rGO(anode)-GO_GO(cathode) (4.92 mF/cm2) setup showed the highest areal specific capacitance. The operating potential window optimization revealed that GO_rGO and GO_rGO(anode)-GO_GO(cathode) setups could maintain EDLC up to 1V window, while the other setups started showing deviations after 0.7 V window. We intend to thoroughly investigate the ILI process for these four different setups and how they contribute to the EDLC mechanism.
CaMKII inhibition has dual effects on spontaneous Ca2+ release and Ca2+ alternans in ventricular cardiomyocytes from mice with a gain-of-function RyR2 mutation
Authors: Sadredini Mani , Haugsten Hansen Marie , Frisk Michael , Louch William E. , Lehnart Stephan E. , Sjaastad Ivar , Stokke Mathis Korseberg
Published: July 2021

Genetically increased RyR2 activity promotes arrhythmogenic Ca2+ release. Inhibition of CaMKII suppresses RyR2 activity and arrhythmogenic Ca2+ release. Suppression of RyR2 activity prolongs refractoriness of Ca2+ release. Prolonged refractoriness of Ca2+ release leads to arrhythmogenic Ca2+ alternans. CaMKII inhibition promotes Ca2+ alternans by prolonging Ca2+ release refractoriness.
Fault Diagnosis Method of the Construction Machinery Hydraulic System Based on Artificial Intelligence Dynamic Monitoring
Authors: Zhou Xin , Lei Xianqing
Published: July 2021

This paper aims to study the fault diagnosis method of the mechanical hydraulic system based on artificial intelligence dynamic monitoring. According to the characteristics of functional principal component analysis (FPCA) and neural network in the fault diagnosis method in the feature extraction process, the fault diagnosis method combining functional principal component analysis and BP neural network is studied and it is applied to the fault of the coordinator hydraulic system diagnosis. This article mainly completed the following tasks: analyzing the structure and working principle of the mechanical hydraulic system, studying the failure mechanism and failure mode of the mechanical hydraulic system, summarizing the common failures of the hydraulic system and the individual failures of the mechanical hydraulic system, and establishing the mechanical hydraulic system. Description of failure mode and effects analysis (FMEA): then, a joint simulation model of the mechanical hydraulic system was established in ADAMS and AMESim, and the fault detection signal of the hydraulic system was determined and compared with the experimental data. At the same time, the simulation data of the cosimulation model were compared with the simulation data of the hydraulic model in MATLAB to further verify the correctness of the model. The functional principal component analysis is used to perform functional processing on sample data, feature parameters are extracted, and the BP neural network is used to train the mapping relationship between feature parameters and fault parameters. The consistency is verified, and the fault diagnosis method is finally completed. The experimental results show that the diagnostic accuracy rates are 0.9848 and 0.9927, respectively, the reliability is significantly improved, close to 100%, and the uncertainty is basically 0, which significantly improves the accuracy of fault diagnosis.
On the Hybrid Power Mean Involving the Character Sums and Dedekind Sums
Authors: Xu Xiaoling
Published: July 2021

The main purpose of this paper is to use the elementary and analytic methods, the properties of Gauss sums, and character sums to study the computational problem of a certain hybrid power mean involving the Dedekind sums and a character sum analogous to Kloosterman sum and give two interesting identities for them.
Bayesian Estimation of Partially Linear Additive Spatial Autoregressive Models with P-Splines
Authors: Chen Zhiyong , Chen Minghui , Xing Guodong
Published: July 2021

In this paper, we aim to develop a partially linear additive spatial autoregressive model (PLASARM), which is a generalization of the partially linear additive model and spatial autoregressive model. It can be used to simultaneously evaluate the linear and nonlinear effects of the covariates on the response for spatial data. To estimate the unknown parameters and approximate nonparametric functions by Bayesian P-splines, we develop a Bayesian Markov Chain Monte Carlo approach to estimate the PLASARM and design a Gibbs sampler to explore the joint posterior distributions of unknown parameters. Furthermore, we illustrate the performance of the proposed model and estimation method by a simulation study and analysis of Chinese housing price data.
A Privacy Protection Method of Lightweight Nodes in Blockchain
Authors: Ge Lin , Jiang Tao
Published: July 2021

Aiming at the privacy protection of lightweight nodes based on Bloom filters in blockchain, this paper proposes a new privacy protection method. Considering the superimposition effect of query information, node and Bloom filter are regarded as the two parties of the game. A privacy protection mechanism based on the mixed strategy Nash equilibrium is proposed to judge the information query. On this basis, a Bloom filter privacy protection algorithm is proposed when the probability of information query and privacy, not being leaked, is less than the node privacy protection. It is based on variable factor disturbance, adjusting the number of bits’ set to 1 in the Bloom filter to improve the privacy protection performance in different scenarios. The experiment uses Bitcoin transaction data from 2009 to 2019 as the test data to verify the effectiveness, reliability, and superiority of the method.
Direct Position Determination for Augmented Coprime Arrays via Weighted Subspace Data Fusion Method
Authors: Qian Yang , Yang Zhongtian , Zeng Haowei
Published: July 2021

Direct position determination (DPD) for augmented coprime arrays is investigated in this paper. Augmented coprime array expands degree of freedom and array aperture and improves positioning accuracy. Because of poor stability and noise sensitivity of the subspace data fusion (SDF) method, we propose two weighted subspace data fusion (W-SDF) algorithms for direct position determination. Simulation results show that two W-SDF algorithms have a prominent promotion in positioning accuracy than SDF, Capon, and propagator method (PM) algorithm for augmented coprime arrays. SDF based on optimal weighting (OW-SDF) is slightly better than SDF based on SNR weighting (SW-SDF) in positioning accuracy. The performance for DPD of the W-SDF method with augmented coprime arrays is better than that of the W-SDF method with uniform arrays.