bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrathin Heterogeneous Inorganic Solid Electrolyte Interphase for Dendrite-Free and Improved Lithium Battery Performance
Authors: Pathak Rajesh , Qiao Quinn
Published: July 2021

Next-generation lithium metal batteries are expected to drive the practical applications that require high energy-density storage, such as, portable electronics and electric vehicles. However, the direct use of metallic lithium causes harsh safety issues, low-grade rate, and cycling performances due to unstable solid electrolyte interphase (SEI) and undesired lithium dendrite growth. Here, the ultrathin bilayer of graphite and SiO2 is deposited on Li foil (Graphite.SiO2@Li) using Radio Frequency (R-F) sputtering to address the inherent problem of lithium metal anode. The R-F sputtered electrodes can be cycled for more than 1300 h and 550 h at a current density of 0.5 mA cm-2 and 1 mA cm-2 respectively to reach a capacity of 1 mAh cm-2. Graphite.SiO2@Li anode coupled with Lithium titanate (LTO) and Lithium Nickel Cobalt Manganese oxide (NMC111) reaches higher capacity retention (96.78% and 98.57%) compared to bare Li (92.31% % and 82.73%) respectively. Higher capacity at higher rates and long stable cycling performances with low voltage hysteresis was achieved with the use of graphite.SiO2@Li anode. The graphite layer lowers the impedance, buffers the volume expansion issue, and helps to electrically connect the plated Li with the bulk Li electrode underneath. The higher electrolyte wettability of SiO2 provides much better Li-ion transportation, and ultrathin SiO2 film allows fast Li-ion diffusion and lithiation/delithiation to slow down the growth of Li dendrites. Besides, its high Young’s modulus form robust SEI, the insulating property of SiO2 blocks the electron transport, and chemical stability prevent side reaction with the liquid electrolyte.
Chemo-Mechanical Model for Internal Stress Impact on Lithium Dendrite Growth
Authors: Meyer Julia , Mukherjee Partha P. , Roberts Scott A. , Harrison Katharine
Published: July 2021

Lithium-ion batteries have the potential for greater efficiency and lifetime than current commercial options; however, there are operation and safety concerns that must be addressed before expanding their applications. During operation lithium dendrites form due to plating on Li-electrolyte surface inhomogeneities, which leads to battery failure once the dendrite reaches the cathode and short-circuits the cell. Addition of mechanical stress due to both internal and external pressures has been observed to decrease the propensity for dendrite growth. However, this addition leads to other complications, including inhomogeneous transport through the separator caused by inhomogeneous contact of a rough Li surface. In this work, we present a mesoscale model of a lithium protrusion brought into contact with a typical porous separator. The model couples mechanical deformation in both the lithium and separator with the electrochemical response during the charging phase. The nature of the model allows these materials to be brought into full or partial contact; the latter creates an electrolyte-filled gap, which drastically changes the electrochemical behavior across the 3-dimensional contact interface. The effects of internal stress and various model properties on the reaction rate across the protrusion surface are explored; through this, the propensity of plating across the interface may be predicted. Specific properties studied include the protrusion shape, separator porosity and modulus, liquid electrolyte diffusivity, and applied current density. Phase maps of the conditions for which dendrite formation is encouraged or suppressed are created and may be used to inform battery manufacturing and material choices.

Supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
Electrolyte Composition Effects on the Formation of the Solid Electrolyte Interphases of Li-Metal Batteries: A Molecular Dynamics Study
Authors: Seminario Jorge M. , Galvez Diego , Ponce Victor
Published: July 2021

We will present our recent effort to develop new materials for batteries using our nanobattery model able to simulate a much smaller battery containing all the main components of an actual size battery. We are testing Li-metal anodes with sulfur- and metal-oxide-based cathodes together with highly concentrated electrolytes as well as with localized highly concentrated electrolytes. Our approach consists on performing ab initio analysis and ab initio molecular dynamics simulations in order to determine energetics properties as well as reactive force fields to perform larger scale reactive molecular dynamics simulations that eventually will allow us to evaluate prospective battery systems based on cycling stability, formation of benign solid-electrolyte interphases, interfacial stability, ion-transport and its mechanisms, electron-transfer, output voltage, current and charge thresholds, battery capacity, ion-pairing, cluster and death lithium formation, dendrite growth, capacity fading. In the present work, we use molecular dynamics simulations to model a TMP-based electrolyte comprising TMP, lithium, and bis(fluorosulfonyl)imide (LiFSI) salt, exploring the effects of salt concentration on solvation and ion transport. A statistical analysis is performed to study ion pairing, clustering, mobility, and coordination of Li-ion with and without small amounts of diluent materials.
Mesoscale Interactions in the Porous Cathode of All-Solid-State Lithium Batteries
Authors: Naik Kaustubh Girish , Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: July 2021

All-solid-state lithium batteries hold great potential to enable next-generation energy storage devices. The electrochemical performance of such solid-state batteries is strongly dependent on the physiochemical interactions underlying the porous cathode microstructure. The spatial arrangement and composition of constituent phases in the cathode determines effective ionic transport properties, electronic conductivity and electrochemically active area. In this work, we connect the interplay between the coupled kinetic and transport processes in the cathode to the distinct internal resistance signatures. The mesoscale underpinnings of the porous cathode are elucidated in the context of electrochemical performance at operational extremes.
A Stable Li Metal Anode with Electrochemically Treated Poly(ethylene oxide) Coating for Lithium Oxygen Batteries
Authors: Lim Hyung-Seok , Kwak Won-Jin , Chae Sujong , Wi Sungun , Li Linze , Wang Chongmin , Xu Wu , Zhang Ji-Guang
Published: July 2021

Rechargeable lithium-oxygen batteries (LOBs) has being considered as one of the most promising candidates for the next-generation high energy-density batteries. The long-term cycling ability of LOBs is closely related to the stability of Li metal anode in an oxygen-rich environment. In this study, a polymer-supported solid electrolyte interphase (PS-SEI) layer generated on Li metal surface was investigated to minimize side reactions between Li metal anode and electrolyte as well as highly reactive oxygen moieties and soluble catalysts (redox mediators, RMs). The improved robustness of the PS-SEI layer can be attributed to uniformly-distributed stiff oxygen-containing components interacted with flexible ionic conductive polymer matrix. In addition, the impedance spectra of the LOBs with a PS-SEI before and after the cycling revealed a stabilized interface between Li anode and the electrolyte. The PS-SEI incresed the cycle life of LOBs by more than 50% compared to the LOBs without PS-SEI under the same testing condition of 1.0 mAh cm-2 at 0.2 mA cm-2. The combination of this protection layer and and an effective redox mediater such as (2,2,6,6-tetramethylpiperidin-1-yl) oxidanyl (TEMPO) further improved the performance of LOBs.
Me-N-C (Me= Fe, Co) Electrocatalysts with EDTA-Derived N for Dopamine Electrochemical Detectionpreferred
Authors: Balkourani Georgia , Molochas Konstantinos , Brouzgou Angeliki , Tsiakaras Panagiotis
Published: July 2021

Neurotransmitters are chemical transporters that exchange signals between neurons and other cells. Measuring their concentrations in vivo is a very challenging procedure, firstly because the extracellular concentrations of neurotransmitters are very low and can change rapidly and secondly because they co-exist with many electroactive neurochemicals in the brain, interfering the neurotransmitters detection. Dopamine (DA) is a catecholamine, modulating many parts of brain circuitry. Abnormal levels of DA are associated with neurological disorders such as schizophrenia, Alzheimer’s and Parkinson’s diseases. Herein, we synthesized low-cost electrocatalysts using a template-free synthesis method with ethylene diamine tetra acetic acid (EDTA)-nitrogen precursor, carbon substrate and Fe or Co nanoparticles. Both electrocatalysts were investigated towards dopamine oxidation reaction. In the figure below, the amperometric response curves of Co-kb-N /GCE (A) to continuous addition of 1 mM DA (red) and 10 mM DA (pink) are presented, with 1100 rpm in 0.1 M KOH (pH=13) at -0.05 and -0.15 V vs. Ag/AgCl, respectively. Additionally, plots of current versus DA concentration and the corresponding linear fitting after the addition of 1 mM DA (Bi) and 10 mM DA (Bii) solution are depicted. Co-kb-N exhibited the most promising behavior, with three linear ranges: 0.1- 0.41 mM, 1- 3.55 mM, 3.75- 4.74 mM and 0.11, 0.48, 2.58 mM limit of detection, as well as 871.4, 571.3, 105.7 μA mM-1 cm-2 sensitivity, with R2 0.99, 0.98, 0.95, respectively.

Figure 1
Mg2+ Solvation Structures and Diffusion Properties in Dimethoxyethane Solutions Using Multimodal NMR Analysis
Authors: Chen Ying , Han Kee Sung , Hu Jianzhi , Mueller Karl , Murugesan Vijay
Published: July 2021

Mg-based secondary battery systems represent a promising advancement over current technology, however a detailed molecular view of the battery components are lacking which prevents the implementation of such technologies. Diffusion behaviors of Mg2+ in electrolytes are usually not as readily accessible as Li+ and Na+ through PFG NMR, due to the low sensitivity and resolution of 25Mg NMR. Herein, we report the evolution of solvation structures and diffusion behaviors in the traditional MgTFSI2/DME based electrolyte using quantitative multinuclear (1H, 19F, 17O) NMR, NMR relaxation, 2D 1H EXSY NMR, as well as PFG diffusion measurements. High resolution 1H NMR reveals bound DME (DME molecules coordinating to Mg2+) and bulk DME (“free” diffusing DME) within solution structure, where the diffusion of bound DME provides informatin about Mg2+ diffusion through a two-site exchange-diffusion model. We concluded that the dominant solvation structure evolves from contact ion pairs (i.e. [Mg(TFSI)(DME)1-2]+) to fully solvated clusters (i.e. [Mg(DME)3]2+) as salt concentration increases or as temperature decreases. This transition is coupled to a phase separation between 0.06 M and 0.36 M. Subsequent analysis is based on an explanation of the solvent rearrangement process and the competition between solvent molecules and TFSI anions for cation coordination. Furthermore, the comparison between diffusion behaviros of Mg2+ and TFSI- reveals the formation of supercluster structures that highly constrain Mg2+ diffusion at high concentrations and low temperatures but present little restricticiton to TFSI- diffusion, properbly due to the long-distance effect of multivalent Mg2+ on DME with suppressed motion under these conditions.
(Invited) Developing Common Descriptors for Plating/Stripping of Divalent Metals in Organic Electrolytes
Authors: Connell Justin G. , Zorko Milena , Agarwal Garvit , Yang Mengxi , Assary Rajeev S. , Liao Chen , Strmcnik Dusan , Markovic Nenad M
Published: July 2021

A significant challenge facing the development of new chemistries for multivalent batteries is the fact that many promising electrolytes are incompatible with either metallic anodes or high voltage cathodes, both of which are required in order for such systems to compete with existing Li-ion batteries. Furthermore, the specific species responsible for delivering ions to the active electrode are generally not known, as solvation structure may change significantly relative to the bulk as solution complexes approach the electrified interface. Many Mg electrolytes in particular rely on the presence of significant concentrations of Cl- to enable reversible metal plating/stripping at the anode, which preclude their use with oxide cathodes due to parasitic reactions that take place at high voltage. Beyond this limitation, however, it is also unclear what the specific role of Cl- is in promoting reversibility in Mg and other multivalent systems, making it challenging to develop general design rules for synthesizing new electrolytes that can avoid the use of Cl- altogether. We have recently revealed that a cooperative effect between Cl- and bis-(trifluoromethane sulfonyl) imide (TFSI-) anions yields the overall more reversible behavior of mixed TFSI-/Cl- electrolytes relative to electrolytes containing only TFSI- – an effect that is general across multiple multivalent systems (i.e., Mg, Zn and Cu). Mechanistic understanding of the role of Cl- in improving reversibility of TFSI-based electrolytes is provided through the combination of electrochemical measurments with computational evaluation of the activity and stability of various TFSI- and Cl-based solution complexes. This cooperative anion effect is generalizable to dual anion electrolytes without Cl- as well, with the strength of anion association to the working cation systematically modifying the electrochemical response in direct agreement with trends predicted by theory. These results further indicate that interfacial speciation indeed deviates from that expected in the bulk, as even nominally weakly-coordinating anions appear to participate strongly in the plating/stripping reactions. Overall, this work points to the existence of a common descriptor for divalent metal plating/stripping – anion association strength – and suggests a set of general design principles for developing new multivalent electrolytes.
Protected Calcium Anodes: Lessons from Native Interphases
Authors: Zavadil Kevin R , McClary Scott A , Long Daniel M , Hahn Nathan T , Kotula Paul G , Jungjohann Katherine L
Published: July 2021

Reversible ambient temperature Ca electrodeposition has thus far been demonstrated in only a few electrolytes. Additional knowledge is required to translate these early successes to electrolytes capable of high coulombic efficiency and stability toward self discharge required for a practical Ca metal ion battery. Calcium borohydride in tetrahydrofuran is promising in both regards, representing an opportunity to develop electrolyte design principles to support a Ca metal anode, despite a low oxidation threshold and low ionicity. Where efficiency and stability are attributed to calcium hydride shown to form during deposition, no direct evidence for the presence of hydride within the interphase has been reported. In an effort to determine how the interphase functions for Ca cation transport, we have conducted compositional and structural mapping of this interphase using analytical transmission electron microscopy, including cryogenic methods. We demonstrate the interphase that forms on the dense Ca deposit is a discontinuous, only partially crystalline oxide that contains B species, not unlike the interphase reported to form in carbonate electrolytes containing the tetrafluoroborate anion at elevated temperature. In this presentation, we discuss how the interphase attributes vary as a function of Ca deposition conditions, including tuned bulk and interfacial speciation and explore ideas of enhancing Ca anode function.

This work was supported by the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Correlating Ion Jumps with Bond Covalency in Solid Electrolytes
Authors: Aleman Johana Dolores , Adelstein Nicole , Garcia Oskar Kenyatta
Published: July 2021

The development of Li-ion solid electrolyte batteries will improve battery safety and potentially energy density compared to conventional Li-ion batteries, which have liquid-electrolytes. Solid electrolytes are inorganic polycrystals, so they cannot catch on fire and resist dendrite growth. However, Li-ion conductivity in the solid-electrolyte is relatively slow compared to liquids, so this project focuses on understanding the diffusion mechanism of binary metal halides for the improvement of other superionic materials. This work is inspired by the high conductivity of α-AgI and is based on previous computational work by the Adelstein lab that showed thermally driven bond fluctuations aid in the conduction of Li-ions in Li3InBr6.

Since bond character is determined by the interaction of the cation and anion and crystal structure, we simulate both Ag and Cu metal halides in various crystal structures. Each crystal structure (α, β, zinc-blende, or rock-salt) is simulated at three temperatures for AgCl, AgBr, AgI, CuCl, CuBr, and CuI to obtain the activation energy barrier. Diffusivity, jump events, and bond character (ionic or polar-covalent) were calculated for each simulation, which allows us to differentiate between different diffusion mechanisms of Ag and Cu. Our on-going investigation into the silver and copper halides aims to test the hypothesis that fluctuations in bond character help superionic diffusion by correlating ion jumps with bond character.
Freeform Lithium Superionic Conductor
Authors: Jung Sung-Kyun , Gwon Hyeokjo , Yoon Gabin , Kim Jusik
Published: July 2021

The key challenge in all-solid-state batteries (ASSBs) is establishing perfect physical contact between rigid components for facile interfacial charge transfer, especially between the solid electrolyte and cathode. Here, we introduce a new class of shapeable inorganic-based solid electrolytes with a liquid-like sublattice that can form intimate contact with the rigid cathode. The electrolyte exhibits extraordinary clay-like mechanical properties (storage and loss moduli < 1 MPa) at room temperature, high lithium ion conductivity (3.4 mS cm-1), and a glass transition below -50 ℃. The unique mechanical features provide liquid-like penetration into the porous cathode and ionic conduction paths for all cathode particles, delivering a high energy density. We propose a design principle that the complex anion formation including Ga, F and a different halogen can induce the clay-like features. Our findings provide new opportunities in the search for solid electrolytes and suggest a new approach for resolving the issues caused by the solid electrolyte–cathode interface in ASSBs.
Characterising Lithium-Ion Electrolytes Via Operando Raman Microspectroscopy
Authors: Fawdon Jack , Ihli Johannes , La Mantia Fabio , Pasta Mauro
Published: July 2021

The successful innovation of high-energy Li-ion battery alternatives requires a comprehensive understanding of their respective electrolyte.1 Full characterisation of liquid electrolytes conventionally requires multiple experimental setups, which can be both time and resource intensive.2,3 Here, we present a unified method for characterising Li-ion liquid electrolytes using operando Raman microspectroscopy in tandem with potentiostatic electrochemical impedance spectroscopy (PEIS). Performing a time-series of 1D Raman line scans to measure electrolyte concentration gradients, and being in tandem with PEIS, allowed for the quantification of the Fickian “apparent” diffusion coefficient, transference number, thermodynamic factor, ionic conductivity and resistance of charge transfer of the electrolyte lithium bis(fluorosulfonyl)imide (LiFSI) in tetraglyme (G4).4 We believe this facile and powerful new experiment is implementable in both academia and industry to understand how novel electrolyte’s properties are influencing the concentration gradient and non-uniform Li+ deposition (dendrite growth).

References

Cheng, X. B., Zhang, R., Zhao, C. Z. & Zhang, Q. Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review. Chemical Reviews
117, 10403–10473 (2017).

Valoen, L. O. & Reimers, J. N. Transport Properties of LiPF6-Based Li-Ion Battery Electrolytes. Journal of The Electrochemical Society
152, A882 (2005).

Hou, T. & Monroe, C. W. Composition-dependent thermodynamic and mass-transport characterization of lithium hexafluorophosphate in propylene carbonate. Electrochimica Acta
332, 135085 (2020).

Fawdon, J., Ihli, J., La Mantia, F., Pasta, M. Characterising Lithium-Ion Electrolytes via Operando Raman Microspectroscopy, (2020). ChemRxiv. Preprint. https://doi.org/10.26434/chemrxiv.13359344.v1
Solving Lithium Dendrite Problems through Structure Design of Advanced Metal Anodes for Lithium Metal Batteries
Authors: Li Wentao , Zhou Yue , Zhang Liqun , Lucht Brett , Sun Xiao-Guang , He Wei , Chen Ke , Koggala Wellalage Dilni Kaveendi
Published: July 2021

Commercial lithium ion batteries use mostly graphite as the anodes, which replaced the original lithium metal at the expense of energy density. Now the performance of graphite based lithium ion battery is approaching its theoretical limit, the holy grail of battery with lithium metal anode is increasingly needed for wider adoption of electric vehicles and renewable energy storage. However, dendrite growth during charge of the battery has been preventing its wide application in rechargeable batteries.

Solid electrolyte and lithium protection, such as polymers and ceramics, has traditionally been the solution for lithium metal anodes. Recently, there are also efforts to prepare 3D microporous electrodes, such as graphene, glass/carbon/copper fibers/scaffolds with or without infused lithium. While these efforts have had some successes in blocking lithium dendrite, lithium deposition still preferentially happens at the interface between the anode and the solid electrolyte/separator, and lithium dendrites can find its way through grain boundary or defects.

LiBAMA has proposed and developed a patent-pending 3D advanced metal anode (AMA) to solve the dendrite problem, by guiding the deposition of lithium instead of blocking the growth of the dendrite. The 3-D electrode’s surfaces directly adjacent to the separator are coated with an artificial passivation/SEI layer that redirects lithium deposition during charging to its interior, thus preventing dendrite formation at the interface. The concept was confirmed by computer simulation of current distribution in finite element analysis, showing uniform current distribution with the AMA, instead of high surface current density with regular 3D electrodes without the SEI. The designed anode has been prepared and evaluated in coin cells. Symmetrical cells with AMAs have completed 500 plating cycles at 8 mA/cm2 and 4 mAh/cm2 without shorting. LFP coin full cells with AMAs have shown 300 cycles with over 90% capacity retention. The technology solves the decades-old dendrite problems and will lead to lithium metal batteries with 500-600 Wh/kg energy density and 30% lower cost than graphite-based lithium ion batteries.

Figure 1
Investigating the Phase Transition of VO2(M) to VO2(R) Via Lithium-Ion Electrochemistry
Authors: Housel Lisa M. , Quilty Calvin , Abraham Alyson , Tang Christopher , McCarthy Alison H. , Renderos Genesis , Liu Ping , Takeuchi Esther S. , Marschilok Amy C. , Takeuchi Kenneth J.
Published: July 2021

Vanadium dioxides exist as different polymorphs, each with unique electrochemical properties. Herein, we investigate the monoclinic to rutile transition of vanadium dioxide using different temperatures. The transition from monoclinic to rutile is characterized using synchrotron-based X-ray diffraction and electrochemical performance is performed using electrochemical impedance spectroscopy and intermittent pulsatile galvanostatic discharge tests in a lithium-ion environment. The experimental results indicate a decrease in ohmic resistance when lithium-ion cells are tested at higher temperatures. Density functional theory calculations also identified a possible LixVO2(M) to LixVO2(R) phase transition during the discharging process. Since the monoclinic to rutile transition corresponds to an increase of electrical conductivity by 2 orders of magnitude this can favorably impact the function of a lithium-based electrochemical cell.
Iron-Based, Symmetric, Non-Aqueous Redox Flow Battery
Authors: Blesch Thomas , Moulin Cabral Diogo , Dong Shuo , Howlett Patrick C. , Macfarlane Douglas Robert
Published: July 2021

The redox flow battery (RFB) is a promising technology for the long-duration storage of energy from domestic- to utility-scale. A RFB stores charge in a liquid electrolyte that is charged and discharged in an electrochemical cell reactor. Since storage and reaction site are separated, energy and power of the system can be scaled independently via electrolyte tank and cell stack dimensions. Iron as one of earth’s most abundant elements is an attractive active material, especially in symmetric RFBs using the same electrolyte on both negative and positive side of the battery. One way to realize such a system is by combining iron with redox-active ligands in non-aqueous solvents.[1],[2]

We study the iron tris(2,2’-bipyridine) complex which shows a metal-centred reversible oxidation and three ligand-based reductions that are solvent-dependent.[3] The influence of electrolyte composition on charge and discharge reactions as well as on viscosity and conductivity is further investigated. Charge-discharge cycling experiments are carried out in 3-electrode H-cell and flow cell setups. We determine failure modes for the positive side due to electrode kinetics and for the negative side due to solubility changes. We propose improvements to this non-aqueous RFB system based on the selection of electrode materials and cycling conditions.

[1] J. Mun et al., J. Electrochem. Soc.
2018, 165, 215-219.

[2] C. X. Cammack et al., DaltonTrans
.
2021, 50, 858.

[3] D. M. Cabral, P. C. Howlett, D. R. MacFarlane, Electrochim. Acta
2016, 220, 347-353.
Insights into Reactivity of Silicon Negative Electrodes: Analysis Using Isothermal Microcalorimetry
Authors: Housel Lisa M. , Li Wenzao , Quilty Calvin , Vila Mallory , Wang Lei , Tang Christopher , Bock David C , Wu Qiyuan , Tong Xiao , Head Ashley , Takeuchi Kenneth J. , Marschilok Amy C. , Takeuchi Esther S.
Published: July 2021

Silicon offers high theoretical capacity as a negative electrode material for lithium-ion batteries; however, high irreversible capacity upon initial cycling and poor cycle life have limited commercial adoption. In this work, an operando isothermal microcalorimetry (IMC) study of a model system containing lithium metal and silicon composite film electrodes was reported on the first two cycles of (de)lithiation. The total heat flow data are analyzed in terms of polarization, entropic, and parasitic heat flow contributions to quantify and determine the onset of parasitic reactions. These parasitic reactions, which include solid−electrolyte interphase formation, contribute to electrochemical irreversibility. To complement the calorimetry, operando X-ray diffraction is used to track the phase evolution of silicon. During cycle 1 lithiation, crystalline Si undergoes transformation to amorphous lithiated silicon and ultimately to crystalline Li15Si4. The solid-state amorphization process is correlated to a decrease in entropic heat flow, suggesting that heat associated with the amorphization contributes significantly to the entropic heat flow term. This study effectively uses IMC to probe the parasitic reactions that occur during lithiation of a silicon electrode, demonstrating an approach that can be broadly applied to quantify parasitic reactions in other complex systems.
Exploring the Influences of Nanoparticle Synthesis-Route and Electrolytic Ions on the Electrochemical Performance of MnFe2O4-Based Supercapacitors
Authors: Rani Barkha , Sahu Niroj Kumar
Published: July 2021

A facile and cost-effective synthesis of MnFe2O4 nanoparticles (MnF NPs) using solvothermal and co-precipitation method are explored. The structure, chemical coating, morphology, surface area, and pore size distribution of the NPs are characterized using XRD, FTIR, Raman, TGA, FESEM, EDAX, BET, and BJH analysis. This work investigates the supercapacitive performance of MnF NPs from two different perspectives; (i) influences of the synthesis methods, and (ii) the effect of solvated electrolytic ion size. The conclusion drawn from the morphological studies indicates that the co-precipitation method is more efficient in synthesizing nanoparticles with a smaller diameter and uniform distribution. The electrochemical performances of the NPs are evaluated using CV, GCD, and EIS techniques in 3.5 M KOH solution. NPs prepared by co-precipitation approach show higher specific capacitance of 1334 F/g at 2.5 A/g while the value for solvothermally synthesized sample is 786 F/g. These enhanced electrochemical properties are attributed to the smaller particle size, presence of an ample number of electro-active sites, better electronic conductivity of MnF, and multiple oxidation states of manganese and iron ions. Furthermore, the effect of electrolyte ionic radii on the electrochemical properties of the prepared samples is studied. The different aqueous electrolyte of alkaline nature is selected for the experiment. 3.5 M of LiOH, NaOH, and KOH are used to explore the effect of solvated ion size on the electrochemical performance of the MnF NPs. A rising trend of specific capacitance is observed according to the ionic mobility (K+ >Na+ >Li+) of the electrolytic cations. The capacitance of solvothermally synthesized MnF NPs is increased nearly twice with changing the cation from Li+ to K+ ions. The specific capacitance observed for MnF NPs synthesized by the co-precipitation approach are found to be 1002, 1125, and 1334 F/g at a current density of 2.5 A/g for LiOH, NaOH, and KOH, respectively. Among these, KOH-based electrolytes exhibit better activity, capacitance retention, rate performance, ionic conductivity, efficient charge or ion diffusion, and relaxation time. Apart from this, mechanistic studies using the Trasatti method and power-law are used to investigate the electrochemical behaviours of the prepared NPs. The study implies that the redox process of the NPs is diffusion controlled. The diffusion process contributes significantly to the overall charge storage properties of the NPs. This study infer that the co-precipitation approach is favorable in terms of time, cost, eco-friendliness and higher charge storage properties whereas KOH-based alkaline electrolyte is the best-suited to achieve better performance of supercapacitor. This suggests that the preparation method of NPs and the electrolytes play significant role on the performance of electrochemical capacitors.
Hydrazine Oxidation Electrocatalysis on Multi-Doped Carbons: Who Does What?
Authors: Eisenberg David
Published: July 2021

Electrocatalysis of hydrazine oxidation, a promising carbon-free fuel, is both a practical goal, and a scientific paradox. Hydrazine is a common reductant in chemical synthesis, yet the onset potential for its electro-oxidation reaction is highly dependent on the catalytic surface. Some excellent catalysts have been developed in recent years towards this goal, designed for direct hydrazine fuel cells and for sensors. Most of these catalysts, however, are either prohibitively expensive (e.g. Pt-based ones), or easily deactivated (e.g Ni-based ones).

We have recently discovered a family of multi-doped carbons with excellent electrocatalytic activity towards hydrazine oxidation in alkaline pH.1,2 They contain many components, all of which were hypothesized as candidates for hydrazine oxidation active sites: from Mo-doped Fe3C nanoparticles, to single-atom metal sites, and to the N-doped, hierarchically porous carbon. They seemed to provide the first example of hydrazine oxidation on carbides. Moreover, they are stable, efficient, and easy to make on a large scale.

We then set out to understand the source of activity in these fascinating materials, and arrived at a range of surprising discoveries. First, we discovered how Mo-doping is actually unnecessary, and how Zn and Cu direct the nanostructure by different mechanisms.2 Then, we demonstrated that an N-doped carbon matrix – completely metal-free – is also highly active toward the reaction.3 At this point, we raised even larger questions: are the carbide nanoparticles even participate in the reaction? What does it really take for a carbon material to electro-oxidize hydrazine? To answer these questions, we combined electrochemical measurements, broad scope material characterization, and mechanistic quantum-mechanical calculations.4

In this talk I will present unpublished and recently published results, clearing the field of hydrazine oxidation on doped carbons, and explaining the individual catalytic, cooperative and structural roles of each component. While much remains to be understood about the activity and selectivity of these elusively simple material, and their excellent performance makes this challenge both technologically and scientifically appealing.

(1) Ojha, K.; Farber, E. M.; Burshtein, T. Y.; Eisenberg, D. Angew. Chem. Int. Ed.
2018, 57, 17168.

(2) Burshtein, T. Y.; Farber, E. M.; Ojha, K.; Eisenberg, D. J. Mater. Chem. A
2019, 7, 23854.

(3) Farber, E. M.; Ojha, K.; Burshtein, T.; Eisenberg, D., J. Electrochem. Soc. 2020, 157, 064517.

(4) Burshtein, T.; Tamakuwala, K.; Sananis, M.; Ioffe, K.; Hirsch, S.; Farber, E. M.; Grinberg, I.; Eisenberg, D., under preparation.
Reduced Electrocatalyst Loading on Vertical Graphene for Lithium Sulfur Batteries
Authors: Li Wenyue , Fan Zhaoyang , Li Shiqi , Bernussi Ayrton
Published: July 2021

Lithium–sulfur batteries (LSBs) represent a promising energy conversion and storage technique for a multitude of applications, ranging from stationary grid storage to mobile electric vehicles and electronic devices. However, the dissolution of intermediate lithium polysulfides (LPSs) into the electrolyte causes the shuttle phenomenon of the soluble LiPSs and the subsequent adverse effects that result in low columbic efficiency and poor cycling stability, among other issues. Numerous methods have been investigated to attack the polysulfide shuttle effect, from physically blocking the diffusion of LPS to chemically immobilize the LPS to catalytic surface[1]. The later strategy is more effective in curbing the LPS diffusion and can also facilitate the LPS redox reaction by reducing their active energies. In this research, one of the promising catalytic materials, nickel cobalt sulfide (NiCo2S4, NCS) was investigated as catalyst to enhance the LSB performance by grafting it to vertical graphene (VG) grown on carbon nanofiber film (CNF) substrate. Different from other reported metal sulfides materials[2], the studied NCS nanosheets possess ultrathin and edge oriented structure, which is realized by the structural regulation function of VG. As a result, this NCS/VG material not only significantly reduces the utilization of NCS catalyst but also enormously improves the conductivity of the hybrid material. When using this free-standing film as catalytic overlayer on top of sulfur cathode, the derived LSB exhibited attractive electrochemical performances of 1000 mAh g-1 specific capacity at 0.3C and 800 mAh g-1 at 1C within 400 cycles for 2 mg cm-2 of sulfur loading and 850 mAh g-1 specific capacity at 0.25C for 6 mg cm-2 of sulfur loading. An areal capacity of 4.5 mAh cm-2 was demonstrated at the 100th cycle at 0.3 C.

[1] S. Li, Z. Fan, Encapsulation methods of sulfur particles for lithium-sulfur batteries: A review. Energy Storage Materials,
2020, 34, 107-127.

[2] M. Zhang, W. Chen, L. Xue, Y. Jiao, et al., Adsorption-Catalysis Design in the Lithium-Sulfur Battery. Adv. Energy Mater.,
2020, 10, 1903008.
(Invited) Hydrogen-Substituted Graphdiyne Ion Tunnel Directing Concentration Redistribution for Commercial-Grade Dendrite-Free Zinc Anodes
Authors: Zhi Chunyi
Published: July 2021

Current aqueous Zn batteries (ZBs) seriously suffer from dendrite issues caused by rough electrode surfaces. Despite significant efforts in prolonging battery lifespans, minimum effort has been devoted to dendrite elimination in commercial-grade cathode loading mass. Instead, demonstrations have only been done at the laboratory level (≤2 mg cm-2). Additionally, new dilemmas regarding change of proton-storage behavior and interface pulverization have emerged in turn. Herein, hydrogen-substituted graphdiyne (HsGDY) with sub-ångström level ion tunnels and robust chemical stability was designed as an artificial interface layer to address these issues. This strategy prolonged the symmetric cell lifespan to >2400 h (100 days), which is 37-times larger than the one without protection (63 h). The simulation of dual-fields uncovered that HsGDY could redistribute the Zn2+ concentration field by spatially forcing Zn2+ to deviate from the irregular electric field. During practical use, the as-assembled full batteries delivered a long lifespan 50 000 cycles and remained stable even at a commercial-grade cathode loading mass of up to 22.95 mg cm-2. This HsGDY-protection methodology represents a great progress in Zn dendrite protection and demonstrates enormous potential in metal batteries.
(Invited) Advanced Carbons for Stable Li, Na and K Metal Battery Anodes
Authors: Mitlin David
Published: July 2021

Metal batteries (MBs) are viewed as highly promising "Beyond Li" energy storage systems with up to twice the energy of commercial LIBs. This includes lithium metal batteries (LMBs), sodium metal batteries (SMBs) and potassium metal batteries (KMBs). There are still major technical challenges with all MBs, however, that prevent commercial adoption. An unstable solid electrolyte interphase (SEI) promotes growth of filament-like dendrites at the anode, leading to electrical shorts and associated safety hazards. This presentation discusses several electrode architecture design examples where carbons with tuned structure chemistry and morphology are employed to (i) create a "philic" surface, thereby promoting electrochemical metal wetting on the current collector, or (ii) form a "phobic" membrane, replacing the unstable native SEI with a more stable artificial one. It is demonstrated that the design rules for cases (i) and (ii) are fundamentally different, and that in addition to wetting of the metal, wetting of the electrolyte has to be controlled. A strong correlation between electrolyte wetting, the SEI structure and uniformity, and metal plating/stripping stability was discovered. This presentation also covers the use of tailored carbons for MB cathodes, highlighting S and SeS -based systems that display covalent bonding and closed pore encapsulation. In addition to Li, covalent/close pore carbon hosts stabilize the much more challenging K and Na systems, suppressing the cycling-induced parasitic shuttle and electrode disintegration. The presented findings were recently published as a series of articles in Advanced Materials and Advanced Energy Materials.
Inter-Bonded Carbon Nanofibers Based Anode for High Areal Capacity Lithium-Ion Battery
Authors: Plateau Tazdik Patwary , Pham Hiep , Sarkar Susmita , Park Jonghyun
Published: July 2021

Improving anode electrode conductivity and boosting mechanical strength of carbon nanofibers (CNFs) is beneficial to fabricate binder-free anode for high areal capacity in Lithium-ion Batteries (LIBs). A typical way to improve CNFs conductivity is adding high conductive transition metals to CNFs precursors. In this work, several ideas are incorporated together to enhance LIB performance. First, CNFs with 3% and 5% nickel is introduced by using electrospinning technique for improving electrical conductivity and capacity, because nickel has high theoretical capacity (718mAh/g) and enhanced electrical conductivity (1.43x107 S/m). Small addition of Nickel was done because higher usage of nickel metal fillers cause volume expansion during cycling which results in poor cell performance. Second, development of strong mechanical connections, enhancement of electron transport by better inter-bonding network among the CNFs is also addressed here. In this study, polyvinylpyrrolidone (PVP)/ polyacrylonitrile (PAN) polymers are used to fabricate the CNFs where the semi-interpenetrating polymer PVP assists in creating inter-bonded morphologies in the nanofibers. Thus, well inter-bonded CNFs showed not only the better areal capacity but also the higher specific capacity. Further an optimum stabilization and carbonization heat-treatment process was also observed. The synergetic effect of adding high conductive Nickel and well-inter-bonded CNFs network represents a favorable anode material with an areal capacity as high as 792.7 μAh/cm2 after 300 cycles at a current density of 1.16 mA/cm2 and excellent cycling stability.
Carbon Nanomaterials for Energy Applications
Authors: Bekyarova Elena
Published: July 2021

Bridging the performance gap between batteries and supercapacitors is an area of active research driven by the increased importance of effective solutions for energy storage. A promising trend in this area is the development of novel materials that afford design of architectures combining the advantages of both energy storage devices. Batteries, which operate based on Faradaic processes taking place in the bulk of the active electrode materials (chemical mechanism of storage), exhibit high energy, but suffer from slow charge and discharge rates. On the other hand, supercapacitors deliver high power at the cost of low energy storage by making use of surface ion adsorption (double-layer capacitance, physical mechanism of storage) and surface redox reactions (pseudo-capacitance). Carbon nanomaterials, including carbon nanotubes and graphene, are potential candidates for the preparation of electrodes operating at high current rates. This talk will discuss the performance of electrodes prepared from carbon nanomaterials and their specific benefits when assembled with nanostructured cathodes into full cells. The cells are characterized for energy density, power density, rate capability and cycling stability.
Graphitic Mesoporous Carbon Thin Film Prepared By Rapid Thermal Annealing for Micro-Supercapacitors
Authors: Bhardwaj Ayush , Pagaduan James , Yu Yongguen , Einck Vince , Nuguri Sravya , Katsumata Reika , Watkins James
Published: July 2021

The miniaturization of electronic devices led to the advent of on-chip power sources with high energy and power density requirement. The development of such miniaturized energy devices further requires the preparation and/or processing of thin films (down to a few nanometers) of active material. Mesoporous carbon possessing both high porosity and conductivity are desired for such applications. However, obtaining thin films of mesoporous carbon on various substrates using commercially viable approaches requires further improvement and investigation.

We have adapted rapid thermal annealing (RTA) as a novel approach to obtain mesoporous carbon. RTA enables rapid heating to temperatures up to 1200oC in just a few seconds and therefore provides a route for complete carbonization within a few minutes. Carbon precursor films comprised of brush block copolymers (BBCP) as sacrificial templates and phenol formaldehyde (PF) resin as a carbon source were prepared. In particular, the self-assembly of polydimethylsiloxane-b-polyethylene oxide (PDMS–b-PEO) BBCP and PF resin led to the formation of microphase-segregated film on various substrates including Si wafer, fused silica, and stainless steel. The PDMS domain in the BBCP fostered strong adhesion to the substrate even after annealing. RTA enabled complete carbonization of the precursor film within only 5 minutes, whereas conventional methods require approximately 500 minutes. Rapid processing at 1000oC resulted in the formation of mesoporous carbon with higher degree of graphitization, which is difficult to achieve with conventional carbonization method. The device prepared via RTA has a capacitance value of 7.0 mF/cm2 at 100mV/s, which is one of the highest values obtained for nanometer-thick carbon-based electrodes. These electrodes maintained a quasi-rectangular shape during the potential vs current scan, even at a scan rate of 20 V/s, which suggests that these materials are promising candidates for applications requiring very high-power density.

The mesoporous carbon structure having high porosity and high conductivity can be further utilized as supports for the deposition of pseudo-capacitance materials to further boost the energy density of the device.

Figure 1
Vision Improvement after Osimertinib Treatment in Paraneoplastic Optic Neuropathy Associated with Lung Adenocarcinoma
Authors: Kubota Masaomi , Tamura Nobumasa , Hayashi Takaaki , Nishijima Euido , Yanagisawa Haruhiko , Kojima Akira , Nakano Tadashi
Published: July 2021

Treatments for paraneoplastic optic neuropathy (PON), a tumor-related autoimmune disease, include immunosuppression, plasma exchange, and immunoglobulin therapies, as well as treatment of the underlying disease. Herein, we describe the clinical course of an older adult patient with PON whose loss of vision improved after switching between epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) treatments for cancer. A 76-year-old woman, who had been treated with gefitinib for lung adenocarcinoma for two years, presented with acute bilateral visual disturbances. Her decimal best-corrected visual acuity (BCVA) was 0.3 in the right eye (RE) and 0.7 in the left eye (LE). Slit-lamp examination and funduscopy showed no abnormal findings. Two weeks later, her BCVA decreased to 0.2 in the RE and 0.01 in the LE. Goldman’s perimetry showed a defect in the lower nasal RE and extensive visual-field loss in the LE. Single-flash electroretinograms showed normal amplitudes. Magnetic resonance imaging revealed left optic neuritis and showed neither metastatic cancer nor multiple sclerosis. Pattern-reversal visual evoked potentials showed decreased P100 amplitudes in both eyes (BE). Based on a diagnosis of PON from clinical findings, methylprednisolone pulse treatment was administered. However, her BCVA became no light perception in BE two months after the first visit. Because the tumor tissue was found to be positive for the EGFR T790M resistance mutation by bronchoscopy, the EGFR-TKI treatment was changed to osimertinib, decreasing the size of the lung cancer lesions. Her BCVA improved to hand motion in BE. Her final BCVA was 0.01 in the RE, counting fingers 10 cm in the LE. She died at the age of 79 years. To our knowledge, no reports have shown improvement in BCVA in patients with PON after changing EGFR-TKI treatments. This report indicates that some patients may develop severe visual dysfunction without early treatment for the primary tumor.