bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Oxygen Vacancy in Copper-Cobalt Spinel Nanostructures for Electrochemical Energy-Storage
Authors: Nath Narayan Chandra Deb , Lee Jae-Joon
Published: February 2020

The incorporation of oxygen vacancies in metal oxides has been reported to remarkably increase their electrochemical performance in water splitting, photoluminescence, and electrochemical energy-storage. The oxygen vacancies are originated by removal of neutral oxygen atoms from the metal oxides, leaving excess electrons in the vacancies. The excess electrons offer high electrical conductivity, huge number of electroactive sites at or within the surface of metal oxides that could facilitate a adsorption/intercalation of anions (e.g., OH-) at or within the electrode surface and diffusion of ions and electrons within the electrode/electrolyte interface for efficient energy-storage. It has been reported that the spinels with the proper oxygen vacancies could exhibit higher capacitance values compared with that for perfect-crystal. The agglomerated nanostructures of the spinels, Cu2Co2O4 are often prepared by conventional solid-phase or solvothermal/hydrothermal methods, which require non-conductive binders (e.g., Nafion and polyvinylidene fluoride (PVDF)) to achieve strong and stable adhesion onto a substrate. In addition, the conventional synthetic method usually requires high-temperature sintering with complicated procedures, which creates morphological deformation and severe aggregation, decreasing the content of electroactive oxygen vacancies. Therefore, the development of a synthetic procedure is one of the most important tasks needed to get effective nanostructures of Cu2Co2O4 with controllable surface morphology, oxygen vacancies/electroactive sites, and electrical conductivity for the application in capacitors as effective electrode materials. In the present report, we directly grew a series of CuxCo3

-

xO4 nanostructures with controllable surface morphology, oxygen vacancies/electroactive sites and electrical conductivity on a stainless steel substrate by a simple and straightforward electrochemical deposition process and applied them as electrodes for electrochemical charge-storage.
Synthesis of Nitrogen-Doped Molybdenum Sulphide and Molybdenum Sulphide/Oxide Nanocomposite As Active Materials for Supercapacitor Electrode
Authors: Kanade Chaitanya Kaluram , Kanade Vinit Kaluram , Hong Seokjun , Kim Taesung
Published: February 2020

The layered transition metal dichalcogenide molybdenum disulphide (MoS2) is an excellent electrode material due to the presence of pseudocapacitance and electric double layer capacitance. However, low rate performance and capacity fading restrict its application in supercapacitor field. The doping and composite formation can tackle these problems easily. The nitrogen doping can increase the electrical conductivity of MoS2, which eventually enhances the supercapacitor performance while the formation of oxide and sulphide nanocomposite may increase the pseudocapacitance of the MoS2 materials. Thus, here we report the synthesis of nitrogen-doped MoS2 and MoO2/MoO3/MoS2 nanocomposite for application in supercapacitor electrode.

The nitrogen doped molybdenum sulphide and molybdenum sulphide/oxide nanocomposite were synthesised using hydrothermally synthesised MoS2 and urea as a nitrogen precursor in a tube furnace. The structural, as well as morphological characterisation, were done to confirm the synthesis of three-dimensional flowerlike MoS2 (Hexagonal) and nitrogen doped MoO2/MoO3/MoS2 nanocomposite using various spectroscopic and microscopic techniques. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern confirm the formation of mixed oxide and sulphide phases during the nitrogen doping process. The X-ray photoelectron spectroscopy (XPS) confirmed the nitrogen doping of the MoS2 nanostructures. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) were used to study surface morphology of synthesised MoS2 and nitrogen doped MoO2/MoO3/MoS2 nanocomposite. The FESEM and TEM show the flower-like morphology for sulphides and rod/plate-like structure for oxide phase of the nanocomposite. The electrochemical analysis were done to study the supercapacitor behaviour of synthesised materials. The electrochemical impedance measurements display increment in conductivity of MoS2 nanomaterials due to nitrogen doping. The highest specific capacitance observed for 1:1 (MoS2: Urea) weight ratio. The nitrogen doped MoS2 with mixed oxide and sulphide phases (MoO2/MoO3/MoS2) showed the nearly four times enhancement in specific capacitance (~129 F/g at 2A/g) than pristine hydrothermally synthesised MoS2 (~34 F/g at 2A/g). Overall, nitrogen doped MoO2/MoO3/MoS2 composite materials can likely to be used for application in supercapacitors.

Figure 1
The Effectiveness of Some Organic Polymers As Corrosion Inhibitors for Carbon Steel and Brass in Acidic Media
Authors: Branzoi Florina , Aricov Ludmila , Baran Adriana
Published: February 2020

Three organic polymers were studied as corrosion inhibitors for carbon steel type OLC 45 and brass in 1M H2SO4 and 1M HCl solution using potentiostatic and potentiodynamic polarization methods, electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and metallurgical microscopy techniques. The polymers involved in the study are three sodium polyacrylates hydrophobically modified with linear and cyclo-dodecyl and respectively, dihexyl chain. We suppose that, these polymers inhibit corrosion of metal electrodes by a protective mechanism can be owed to either the adsorption of inhibitor molecules forming a protective film or obtaining a insoluble compound and repairing the porous oxide layers. Experimental data showed that these polymers achieved a significant inhibiting action on brass and carbon steel corrosion and act that a mixed corrosion inhibitors and it could be proved by the effects of polymers on the electrochemical properties of metal electrodes. The adsorption of the polymers on the electrodes surface obeys to the Langmuir isotherm model. The temperature influence on the corrosion behaviour of the metal electrodes in 1M H2SO4 and 1M HCl with and without the inhibitor at 500 ppm was analyzed in the temperature domain from 293 to 313 K. The negative value of thermodynamic parameter like Gibbs free energy of adsorption shows the spontaneity of adsorption process. The experimental results indicated that the corrosion rate have been meaningfully reduced in inhibited solutions when in comparison with the corrosive medium and to increase of the protection effect. Moreover, characterization utilizing FT-IR confirms the adsorption of inhibitors and the constitution of corrosion products on the working electrode surface. EIS and potentiodynamic polarization results demonstrate its corrosion protection capacity. The examined polymers exhibited very good inhibition properties for OLC 45 and brass electrode in 1M H2SO4 and 1M HCl medium while the corrosion current density decreased and the inhibitor efficiency increased with increasing inhibitors concentrations.
Enhancing Mechanical and Corrosion Properties of Electrodeposited Ni- Pr6O11 Composite Coatings Via Stabilizing Agents
Authors: England Jennifer , Ngo Ngan , Golden Teresa
Published: February 2020

Integrating nanoparticles into nickel coatings has been shown to increase the corrosion and mechanical properties of these coatings. The structures of CeO2 and Pr6O11 nanoparticles are similar, and extensive studies on Ni-CeO2 composite coatings have shown increased mechanical and corrosion properties, but there is sparse research on Ni-Pr6O11 composite coatings. However, praseodymium oxide has the potential to change phases upon heating or cooling, increasing the oxygen vacancies and affecting corrosion resistance in certain environments. Praseodymium oxide nanoparticles naturally agglomerate in the electrolyte solution making it difficult to disperse in electroplating solutions. This research studies various stabilizing agents for praseodymium oxide in electrolyte solutions. Electrodeposition of nickel-praseodymium oxide nanocomposites onto metal substrates has been performed with varying concentrations of praseodymium oxide nanoparticles present in the nickel plating bath. Sodium citrate (SC) addition acts as a stabilizing agent for the nanoparticles when added to the electrolytic bath. Up to 30 g/L praseodymium oxide nanoparticles were incorporated into the nickel coating using electrodeposition. The morphology, formation, composition, and hardness of the produced nickel-praseodymium oxide nanocomposite were investigated using scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and microhardness measurements. Potentiodynamic polarization, electrochemical impedance spectroscopy, and exposure to chloride solutions were used to investigate the corrosion resistance properties of the nanocomposites.

Figure 1
Magnetic Field Effect on Anodic Dissolution Behavior of Iron in Sodium Perchlorate Solution
Authors: Cai Shuangwei , Tang Yuanjie , Ning Fei , Ling Sichun , Cui Tongming , Ma Jiarong , Lu Zhanpeng
Published: February 2020

It has been reported that magnetic field affects the anodic dissolution and passivation behavior of iron in acidic, neutral, slightly alkaline solutions. Perchlorate solution has been used in the mechanistic study of anodic dissolution mechanism of iron. In this study, the effects of 0.4T magnetic field on the electrochemical behavior and corrosion morphologies of iron in sodium perchlorate solution were studied by optical microscope (OM), scanning electron microscope (SEM) and several electrochemical methods such as potentiodynamic polarization curve and potentiostatic polarization. Magnetic field was placed horizontally and parallel to the working electrode. The anodic polarization curves show that magnetic field did not have strong effect on anodic current at the potential before the transpassivation potential. In the transpassivation range, magnetic field increased the anodic current, increased the slope of the i/E curve. After the potentiodynamic polarization curve measurements up to 2.0V(SCE), severe electrode thinning was observed under both 0T and 0.4T. Macroscopically uniform dissolution was observed on the electrode after measurements under 0T, while locally accelerated thinning was found on the iron electrode after the measurements under 0.4T, showing the accelerating effect of magnetic field on the anodic dissolution at the edges of the electrode along the horizontal direction, as the result of uneven distribution of the actual magnetic field flux density. Potentiostatic polarization measurements show that magnetic field decreased the anodic current density in the passive range, where the electrode was not significantly affected by magnetic field due to low current density. The accelerating or inhibiting effect of magnetic field can be interpreted based on the magnetohydynamic driving force and the magnetic field gradient driving force theory.

Figure 1
Using Boron-Doped Diamond Electrodes for Organic Synthesis
Authors: Waldvogel Siegfried R. , Haupt John , Berger Michael , Rodrigo Eduardo
Published: February 2020

The use of electrochemistry for the generation of reactive intermediates can have major advantages towards conventional synthetic strategies. Less or no reagent waste is produced and new reaction pathways are accessible. In this context, we present the use of boron-doped diamond anodes for the sustainable synthetic approach to technically relevant and valuable dialkoxylated toluene derivatives. With BDD anodes the scope of the conversion is signbificantly expanded. The general benefits of these innovative carbon electrodes are outlined.
High Capacity, Solid State Lithium Sulfur Battery with Ceramic Electrolytes
Authors: Choi Pyoungho , Svensen Alexander R , Sanghadasa Mohan
Published: February 2020

Solid-state lithium-sulfur (Li-S) batteries with non-flammable, inorganic solid electrolyte can achieve a specific energy of 400 Wh/kg at low cost. The main technical challenges for this type of battery are i) developing a solid electrolyte that is highly conductive (>10-2 S/cm) with a large electrochemical window, ii) creating a large interface area in the cathode, and iii) ensuring low interface resistance between the electrolyte and electrodes. In addition, the solid electrolyte should be made thin but capable of being manufactured on a large scale.

New Li-S-Br-Si-Sn solid electrolytes have been prepared via ball-milling and heat treatment. The elemental composition and ball milling conditions (rpm, etc.) are optimized to get high ionic conductivity (>10-2 S/cm). Electrochemical stability window and ionic conductivity of the solid electrolytes are determined. All solid-state Li-S cells are fabricated by coating solid electrolyte on the cathode and attaching lithium on the electrolyte surface. Cathode is prepared by coating a slurry made of nanoscale sulfur, electron conductor (e.g., graphene), solid electrolyte, and binder on aluminum foil. A number of solvents and binders are investigated to form a homogeneous slurry with minimal agglomeration of particles like sulfur to generate high electrochemical interface area and desirable 3-D transport network for electrons and lithium ions.

The incorporation of binder in the solid electrolyte layer increases the electrochemical resistance of the layer. It is important to use a binder that offers a favorable trade off of lower resistance due to a thinner layer of solid electrolyte being possible and higher resistance due to the binder inhibiting transport of lithium ions. The composition, particle size, degree of compacting, thickness, and structure of cathode materials influence the transport of charge carrying species as well. The effect of binder on the resistance of solid electrolyte bulk and at the solid electrolyte-electrodes interfaces are characterized by AC impedance. Electrochemical performances of the solid-state Li-S cells will be presented. Some suggestions on developing solid electrolyte materials, manufacturing thin electrolyte film, designing the electrochemical interfaces, increasing sulfur loading in the cathode, and maintaining initial morphology of the cathode during the electrochemical processes will be discussed.
Polysulfide-Shuttle Control in Lithium-Sulfur and Sodium-Sulfur Batteries with Polymer-Coated Solid-State Electrolytes
Authors: Yu Xingwen , Manthiram Arumugam
Published: February 2020

The emerging lithium-sulfur (Li-S) batteries are gaining much attention as a promising next-generation energy storage technology.1 An analogous battery system with a sodium-sulfur chemistry has recently started to receive considerable attention as well.2 The electrochemical mechanism of the Li-S and Na-S batteries is quite similar and the charge-discharge processes of these two batteries involve the formation of soluble polysulfide intermediate species. Therefore, the development of both of these two battery systems is facing a critical obstacle due to the so-called “polysulfide-shuttle” behavior during cell operation.3, 4 Although a lot of efforts have been attempted to address such a challenge since it has been recognized many years ago, there is still a lack of reliable approaches that can fully prevent the polysulfide-shuttle without bringing any other negative effects to the Li-S or Na-S cell systems.

Herein we present an alternative strategy to suppress the polysulfide-shuttle in Li-S and Na-S batteries with, respectively, a Li+-ion conductive and a Na+-ion conductive solid-state electrolytes.5, 6 However, the use of a solid electrolyte usually brings an additional challenge in maintaining an adequate ionic interface between the lithium or sodium anodes and the solid electrolytes. Therefore, a strategic approach by coating the solid-state electrolytes with a thin layer of a polymer has been developed. The polymer coating on the ceramic solid-state electrolyte offers a facile interface with the metal electrodes. Both the Li-S batteries and the Na-S batteries with the polymer-coated solid-electrolyte membrane show enhanced cycling stability.

References

X. W. Yu and A. Manthiram, Accounts Chem Res, 2017, 50, 2653-2660.

A. Manthiram and X. W. Yu, Small, 2015, 11, 2108-2114.

Y. X. Wang, B. W. Zhang, W. H. Lai, Y. F. Xu, S. L. Chou, H. K. Liu and S. X. Dou, Adv Energy Mater, 2017, 7, 1602829.

A. Manthiram, X. W. Yu and S. Wang, Nat Rev Mater, 2017, 2, 16103.

X. Yu and A. Manthiram, Adv Funct Mater, In Presss, doi.org/10.1002/adfm.201805996.

X. W. Yu, Z. H. Bi, F. Zhao and A. Manthiram, Adv Energy Mater, 2016, 6, 1601392.
Porous PEO-Silica Hybrid Solid Electrolyte for All-Solid-State Lithium Ion Batteries
Authors: Weldekidan Ephrem Terefe , Hornebecq Virginie , Lebouin Chrystelle
Published: February 2020

Dry polymer electrolytes based on poly (ethylene oxide), PEO, and Li-salt complexes are one of the most cheapest, environmentally friendly and promising materials for developing safe, cheap and durable all-solid-state Li-ion batteries. The rigid structures that are interesting from the point of view of application in all-solid-state battery cells are characterized by low conductivity at ambient temperatures. Dispersion of oxide nanoparticles inside the PEO-matrix greatly improves the physicochemical properties of the complex due to the physical interaction between the grains and the polymer matrix. Unfortunately, such a great effect drops at high loading-content, mostly above 10 wt%, owing to agglomeration of the nanoparticles and the consequence Li-ion blocking effect.

In our work, we have proposed a novel approach that leads to a porous composite electrolyte consisted of higher weight fraction of nanoporous silica than PEO polymer. Here, the polymer-salt complex is being entirely soaked inside the mesoporous silica matrix that offers the mechanical support for the electrolyte. To do this, the walls of silica pores are tailored in the controlled manner with low molecular weight PEO polymer chains. The studied system that contained 70 to 80 wt% of SiO2 showed high conductivity, excellent mechanical strength and wide electrochemical potential window. Textural and structural properties of the starting materials and the hybrid electrolytes will be presented. Furthermore, the electrochemical properties of the porous electrolytes will be discussed to demonstrate the feasibility of our materials as solid electrolytes in all-solid-state Li-ion battery cells.
New Polymer Electrolytes for Safe All Solid-State Lithium Metal Batteries
Authors: Martinez-Ibañez Maria , Aldalur Itziar , Sánchez-Diez Eduardo , Oteo Uxue , Piszcz Michal , Zhang Heng , Armand Michel
Published: February 2020

Driven by the growing demand in energy and the challenge of finding new green energy sources to replace the excessively used fossil fuels, electrochemical energy storage arises as the key alternative to meet the needs of current society. Among all the available electrochemical storage devices, lithium-ion batteries (LIBs) have been extensively investigated as the most suitable choice. Besides, there has been an increasing interest in the research of rechargeable lithium metal batteries (LMBs), where a higher energy density can be achieved compared to the state of art LIBs technologies, due to the high specific capacity provided by lithium metal electrode.

As one of the most critical components, the choice of the electrolyte is very important for preparing safe and high performance LMBs. Most of the commercial batteries are built up with liquid electrolytes based on lithium salts and organic solvents. However, safety concerns such as volatilization, flammability and explosion has tipped the scale in favor of the search of solvent-free solid electrolytes, for which solid polymer electrolytes (SPEs) emerge as one of the most promising choices. In addition to the excellent flexibility, ease of processing and low cost, SPEs can mitigate the Li dendrite growth that takes place in conventional liquid electrolytes, attenuate the interfacial resistance, and improve the electrode-electrolyte compatibility compared to their inorganic solid electrolytes counterparts. Nevertheless, the low Li-ion conductivity, several orders of magnitude lower than those of the conventional liquid electrolytes, remains as the major hindrance towards the practical deployment of all solid-state lithium polymer batteries (ASSLPBs).1,2 Moreover, SPEs are usually characterized by a low lithium-ion transference number (T
Li
+ < 0.5) and consequently are more susceptible to polarization phenomena that eventually limit the power density and cycle life of ASSLPBs.3 Thus, studies on new polymer electrolytes is urgent to improve the performance of ASSLPBs and meet the market requirements.

Inspired by these challenges, in this presentation the performance of new flexible and highly conductive SPEs is provided. Furthermore, the role of different additives on the performance of novel single lithium-ion conducting solid polymer electrolytes (SLIC-SPEs) is elucidated.

References:

Mauger, A., Armand, M., Julien, C. M. & Zaghib, K. Challenges and issues facing lithium metal for solid-state rechargeable batteries. J. Power Sources
353, 333–342 (2017).

Fan, L., Wei, S., Li, S., Li, Q. & Lu, Y. Recent Progress of the Solid-State Electrolytes for High-Energy Metal-Based Batteries. Adv. Energy Mater.
1702657, 1702657 (2018).

Zhang, H. et al. Single lithium-ion conducting solid polymer electrolytes: advances and perspectives. Chem. Soc. Rev.
46, 797–815 (2017).
Engineering Lithium Metal Surface to Enable Long-Term Cycling with Carbonate-Based Electrolytes
Authors: Huang Jinhua , Peebles Cameron , Cheng Gang , Strand Dee , Zhu Ye
Published: February 2020

The continued commercialization of electric vehicles in the transportation industry relies on developing high energy density batteries capable of long cycle life. Of all battery anode materials being studied, lithium (Li) metal affords the highest theoretical capacity (3,860 mAh/g) and lowest electrochemical potential (-3.04 C vs SHE) which offers the highest specific energy density. While Li-ion batteries are capable of delivering energy densities of 400-600 Wh/kg-1, the development of Li-S and Li-air batteries may boost this number to ~650 and ~950 Wh/kg-1, respectively. However, significant progress towards the passivation of Li metal anodes must occur before any of the anode’s potential can fully be realized. Issues with Li dendrite formation, anode volume expansion and continual SEI buildup often result in significant safety concern and poor cycle life of Li metal batteries. To circumvent these problems the use of electrolyte additives, high salt concentration electrolytes and the formation of Li metal anode interfaces have been studied. However, the intrinsic high reactivity between Li metal with conventional Li ion electrolyte (organic carbonated-based solvents) makes it extremely difficult to overcome these problems.

To this end, Wildcat Discovery Technologies has developed both in situ and ex situ surface passivation method for Li metal to significantly boost the cycling performance of Li metal batteries. Thanks to Wildcat proprietary high-throughput technology, we are able to screen numerous passivation materials in combination with a variety of electrolyte compositions. As a result, we found several protection layers of the Li metal anode surface that showed significant improvement on cycling even at 0.9mA/cm2 charging current.
Mechanical Properties of Lithium Metal for Next Generation Batteries
Authors: Masias Alvaro , Felten Nando , Sakamoto Jeff
Published: February 2020

Recent technological innovations such as electrified vehicles and personal electronics have enabled by meaningful advances in lithium ion batteries. Due to long term investment in battery materials and manufacturing, this technology has improved at a relatively steady 8% per year (in terms of specific energy, Wh/kg) since introduction in 1991. To increase the rate of electrified vehicle adoption, revolutionary improvements in battery technology are needed beyond what is currently available.

Currently, three chemistries comprise the next generation battery direction; solid-state (SS), lithium-sulfur and lithium-air. All of these chemistries would benefit from the use of lithium metal anodes as one of the primary means of improving energy density. A SS separator of comparable dimensions as a conventional polyolefin separator could lead to ~100% improvement in cell energy density by enabling metallic lithium anodes [1]. Despite the considerable interest and dependence on lithium anodes in future generation batteries, its mechanical properties are poorly understood. The successful integration of pure lithium metal anodes will require understanding and predicting its mechanical behavior under static and cycling conditions.

Recently our group investigated the elastic, plastic and creep behavior or lithium metal [2]. This presentation will extend the scope from our previous study emphasizing general property characterization to more battery specific mechanical environments, specifically aspect ratio and strain speed. Modern lithium ion battery electrodes having large surface area to volume ratios yielding low aspect ratios which are very different than traditional mechanical testing (i.e. 2 to 4). Additionally there is growing interest in fast charge/discharge, resulting in relatively short periods of mechanical compression, again different from traditional strain speeds (i.e. 1x10-3 sec-1). The impact of aspect ratio and strain rate on lithium’s mechanical properties will be shown.

REFERENCES

[1] Albertus, P. et al. Nature Energy, 3 (2018) 16-21.

[2] Masias, A. et al. J. Mat. Sci., 54(3) (2018), 2585-2600.
Pristine or Highly Defective? Understanding the Role of Graphene Structure for Stable Lithium Metal Plating
Authors: Mitlin David
Published: February 2020

We are the first to examine the role of graphene host structure/chemistry in plating-stripping in lithium metal anodes employed for lithium metal batteries (LMBs). Structural and chemical defects are bad since highly defective graphene promotes unstable solid electrolyte interphase (SEI) growth. This consumes the FEC additive in the carbonate electrolyte and is correlated with rapid decay in CE and formation of filament-like Li dendrites. A unique flow-aided sonication exfoliation method is employed to synthesize "defect-free" graphene (df-G), allowing for a direct performance comparison with conventional reduced graphene oxide (r-GO). At cycle 1, the r-GO is better electrochemically wetted by Li than df-G, indicating that initially it is more lithiophilic. With cycling, the nucleation overpotential with r-GO becomes higher than with df-G, indicating less facile plating reactions. The df-G yields state-of-the-art electrochemical performance; stable plating at 0.5 - 4 mA/cm2, areal capacity up to 2 mAh/cm2, cycle 1 CE at 98% and cycle 100 CE at 94%. With df-G the post cycled metal surface is relatively smooth and dendrite-free. Conversely, r-GO templates have CE rapidly degrade from the onset, with extensive dendrites after cycling. Extensive SEI growth and associated FEC depletion with r-GO are further confirmed by electrochemical impedance analysis and surface science methods (XPS). We therefore propose the following design rule for next-generation supports for LMBs: An ideal architecture will promote copious heterogenous nucleation of the plating metal, shielding it from the electrolyte. In addition, it is essential that the host is itself non-catalytic towards SEI formation.
A Lithiophilic Scaffold of Three-Dimensional Free-Standing Silver Nanowire Aerogels for Stable Lithium Metal Batteries: In Operando xrd Investigation
Authors: Phattharasupakun Nutthaphon , Wutthiprom Juthaporn , Duangdangchote Salatan , Bunyanidhi Panyawee , Sawangphruk Montree
Published: February 2020

Although lithium metal is the most attractive anode materials in rechargeable batteries because of its high theoretical specific capacity (3,860 mAh g-1) and lowest electrochemical potential (-3.04 V), three problems including inhomogeneous lithium deposition, high chemical reactivity with electrolyte, and infinite relative volume expansion during lithium plating and stripping processes still hinder its practical applications. Several methods have been introduced to solve these problems including the use of artificial SEI layer, solid-state electrolytes, host materials. However, all such approaches mainly focused on the final stage of dendritic lithium with less consideration on the initial stage of lithium nucleation. Herein, we propose a new strategy to encapsulate metallic lithium within a lithiophilic scaffold of three-dimensional free-standing silver nanowire aerogel electrode (AgNWAs) which can control the position and morphology of plated lithium at the initial nucleation stage leading to a good coulombic efficiency of 98% after 100 cycles (400 h) in a corrosive carbonate-based electrolyte without any additives. The phase transformation mechanism of Li-AgNWA alloy half-cell and lithiated-AgNWA//LFP full-cell during lithiation/de-lithiation processes is also fundamentally investigated by in operando XRD measurement. In addition, the lithiophilic properties comparing between the bare AgNWAs, Li-AgNWA alloy, and planar Cu electrode are also confirmed by means of DFT calculation. This proposed strategy demonstrates the possible practical use of high-energy rechargeable lithium-metal battery in the next-generation energy storage technologies.
Investigation of Li Ion Dynamics in Garnet Oxide Li6.5La3Zr1.5Ta0.5O12 Using Molecular Dynamics Simulation
Authors: Dai Jin
Published: February 2020

To overcome the safety issue of liquid electrolytes in conventional lithium-ion batteries, various solid-state inorganic electrolytes have been studied. Among them, lithium garnet oxides have been attracting research interests due to their high ionic conductivity, Li7-xLa3Zr2-xTaxO12 (LLZTO) with have a at room temperature with a maximum value around x = 0.51,2.

There are two different structures of lithium garnet oxides, a cubic structure with space group Iad and a tetragonal phase with space group I41/acd. The cubic structure has two types of Li sites, i.e., tetrahedral (Td) 24d sites and octahedral (Oh) 48g sites. The tetragonal structure has four types of Li sites, i.e., Td-8a, Td-16e, Oh-16f, and Oh-32g sites. The fully empty 16e sites and fully occupied the other sites in tetragonal structure makes its conductivity about 2 orders lower than the cubic phase. However, the complexity of structure hindered the understanding of the mechanism of lithium ion conduction.

In this paper, we performed molecular dynamics (MD) simulation on Li6.5La3ZrTaO12 based on classic MD simulation from both the interatomic potential and DFTB methods to study its structure and properties including lattice parameters, diffusion parameters, ionic conductivities, dielectric constants, and elastic moduli. The results are extracted through correlation function that was used for simple liquids3. The consistency of our results with the reported experimental ones helped us to understand the Li diffusion mechanism.

References

(1) Y. X. Wang and W. Lai "High Ionic Conductivity Lithium Garnet Oxides of Li7-xLa3Zr2-xTaxO12 Compositions," Electrochem. Solid State Lett.
2012, 15, A68-A71. http://dx.doi.org/10.1149/2.024205esl

(2) Y. T. Li, J. T. Han, C. A. Wang, H. Xie, and J. B. Goodenough "Optimizing Li+ conductivity in a garnet framework," J. Mater. Chem.
2012, 22, 15357-15361. http://dx.doi.org/10.1039/c2jm31413d

(3) In Theory of Simple Liquids (Fourth Edition); J.-P. Hansen and I. R. McDonald, Eds.; Academic Press: Oxford, 2013, p i.
In-Situ Analysis of Nucleation and Growth of Transition Metal Oxalate Particles As Precursors for Battery Active Materials Via Time Evolution of Solution Composition and Particle Size Distribution
Authors: Dong Hongxu , Wang Anny , Smart Guilermo , Johnson Dave , Koenig Gary
Published: February 2020

The increasing demand on battery performance including energy density and cycle life requires more precise control over phase purity of the active materials and the electrode microstructures. Both of these properties are closely related to constituent particle composition and morphology. Coprecipitation is a popular synthesis route to produce precursors for electroactive, multicomponent transition metal oxides for many applications, including energy storage. Coprecipitation has advantages in that it is scalable, results in homogeneous mixing of transition metal cations, and additionally results in particles that with appropriate processing provide morphology tunability. Understanding the kinetics of the nucleation and particle growth during coprecipitation from a multicomponent blend solution is necessary for rational control of particle composition and morphology. In this talk we will demonstrate a combination of techniques to successfully obtain the in-situ particle size distribution and solution composition. The combined information was used to determine the reaction rate and mechanisms of particle nucleation and growth. The techniques developed in this study can also be applied to other multicomponent coprecipitation systems to guide their particle synthesis.
Centrifugally Spun α-Fe2O3/TiO2/Carbon Composite Fibers as Binder-free Anodes for Lithium Ion Batteries
Authors: Gonzalez Gabriel , Elizondo Antonio , Ayala Jonathan , Lopez Jorge , Alcoutlabi Mataz
Published: February 2020

In the present work, results on the electrochemical performance of flexible and binder-free α-Fe2O3/TiO2/Carbon composite fiber anodes for lithium ion batteries (LIB’s) are reported. The composite fibers were produced via centrifugal spinning and subsequent thermal histories. The fibers were prepared from a precursor solution containing PVP/Iron (III) acetylacetonate/Titanium (IV) butoxide/Ethanol/Acetic acid followed by oxidation at 200°C in air and then carbonization at 550°C under flowing Argon. The morphology and structure of the composite fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). These ternary composite-fibers anodes showed improved electrochemical performance compared to the pristine TiO2/C and α-Fe2O3/C composite fiber electrodes. The ternary α-Fe2O3/TiO2/C composite fibers also showed superior cycling performance with a specific capacity of 340 mAhg-1 after 100 cycles at a current density of 100 mAg-1 compared to 61 mAhg-1 and 121 mAhg-1 for TiO2/C, and α-Fe2O3/C composite electrodes respectively. The improved electrochemical performance and the simple processing method of these metal oxides/C composite fibers makes them promising candidates for next generation and cost-effective flexible binder-free anodes for LIBs.
All-Solid-State Lithium Batteries Assembled with Surface-Modified Lithium Electrode
Authors: Min Ji Yun , Son Hyebeen , Woo Hyun-Sik , Kim Dong-Won
Published: February 2020

Since the use of lithium metal ensures a high specific capacity of 3,862 mAh g-1,the lithium metal batteries can be one of the attractive candidates for achieving high energy density. In order to obtain good cycling stability and enhanced safety, it is crucial to suppress the lithium dendrite formation on the lithium metal surface and reduce the interfacial resistance between the electrode and electrolyte. According to previous studies, there are several approaches to address the above issues; formation of protective layer on the lithium surface, morphology control of the lithium metal and use of additives. As the protective layer, the polymer-based thin layer has a critical drawback of poor mechanical strength, and thus addition of inorganic particles can be a solution to enhance its mechanical strength. In this work, we applied a composite protective layer composed of ion-conductive polymer and inorganic particles to all-solid-state lithium batteries, which effectively suppressed the lithium dendrite and relieved the interfacial resistances during cycling, resulted in improvement of the cycling stability of lithium metal batteries.
Enhancement of the Cycling Performance of Sodium-Metal Cells By Use of a Conductive Polymer Additive
Authors: Choi Jin-Yi , Park Myung-Soo , Veerasubramani Ganesh Kumar , Kim Dong-Won
Published: February 2020

Among a variety of energy storage devices, sodium-ion batteries have received considerable attention as a promising alternative to lithium-ion batteries due to the natural abundance, distribution and cost of sodium resources. In order to achieve higher energy density, the cell voltage should be high enough. There have been a lot of studies on high-voltage cathodes for sodium-ion batteries, and Na3V2(PO4)2F3(NVPF) is one of the promising cathode materials. However, the cells assembled with NVPF exhibit poor cycling performance at high voltage due to electrolyte oxidation and low electronic conductivity of cathode material. In our work, we added amino-anthraquinone (AAQ) into the electrolyte solution as an additive, which can be electrochemically oxidized to poly(amino-anthraquinone) (PAAQ) on the surface of the cathode material. The conductive PAAQ layer formed on the cathode improved the electronic conductivity of NVPF and enhanced its electrochemical performance. The cycling performance of Na/NVPF cells assembled with electrolyte containing AAQ additive was evaluated and the detailed mechanism for improvement of cycling performance was investigated.
Carbon Nanotubes/Graphene Composites Treated By Nitrogen-Plasma and Covered By Porous Cobalt Oxide through Galvanostatic Electrodeposition As Well As Annealing for Anode Materials of Lithium-Ion Batteries
Authors: Lin Chuen-Chang , Wu An-Na , Jiang Shun-Hong
Published: February 2020

Carbon nanotubes/graphene composites are directly grown on nickel foil without additional catalysts by chemical vapor deposition (CVD). Next, to improve the anchoring and uniform dispersing of Co3O4 onto carbon nanotubes/graphene composites, the carbon nanotube/graphene composites are modified by radio frequency (RF) nitrogen-plasma. Then the porous Co(OH)2 thin films are galvanostatically electrodeposited onto N-doped carbon nanotubes/graphene composites at different cathode currents and time periods. Finally, porous Co(OH)2 is transform into porous Co3O4 by annealing. The specific capacity (1290 mAh g
-1
) reaches a maximum at the galvanostatic electrodeposition condition (current = 1.5 mA and time = 300 s). Furthermore, cobalt oxide/N-doped carbon nanotubes/graphene composites possess higher specific capacity and better electrochemical stability in comparison to cobalt oxide/carbon nanotubes/graphene composites.
Challenge and Perspective of Interface between Li Metal and Llzo in Solid State Battery
Authors: Guo Kevin
Published: February 2020

The solid-state battery is becoming a promising technology beyond the current Li Ion battery. There are various candidates for the materials in solid-state battery, and utilizing LLZO as solid-state electrolyte and Li metal as anode material shows great potentials due to the advantages in safety, energy density, conductivity, chemical stability and electrochemical stability. However, the compatibility between the anode (Li metal) and electrolyte (LLZO) is very different from the traditional Li ion battery. The interface between LLZO and Li metal generates high resistance for the Li ion transfer and the interface is dynamic during the stripping and plating cycles. Also, some studies show that LLZO is not free of Li dendrites during plating. There are extensive studies on improving ion transfer between Li metal and LLZO and eliminating the Li dendrite formation on LLZO but no convincing solutions are available yet. These issues may become more challenging when applying LLZO/Li metal in EV/HEV batteries because of special requirements in safety, power and energy density from automotive applications. This work will review the current research status on interface between LLZO and Li metal, address challenges from automotive application, analyze the technology gap, and discuss the perspectives of future technology.
The Effect of Support Salt on Penetration Depth of Reaction of Electrochemical Reduction of Sulfur into Volume of Positive Electrode of Lithium-Sulfur Batteries
Authors: Karaseva Elena , Kuzmina Elena , Kolosnitsyn Dmitrii , Melnikova Anna , Shakirova Nadezhda , Kolosnitsyn Vladimir
Published: February 2020

Lithium-sulfur batteries are batteries with a liquid cathode. Electrochemical transformations of sulfur and the products of its reduction (lithium polysulfides and lithium sulfide) occur on the surface of carbon particles, forming a porous carbon conductive matrix (porous carbon electrode).The depth and rate of electrochemical transformations of sulfur and lithium polysulfides are determined by both the properties of the carbon matrix (porosity, specific surface area, electrical conductivity, sorption capacity towards sulfur and lithium polysulfides) and the properties of electrolyte systems. One of the most important parameters of a porous electrode is the characteristic length - the penetration depth of the electrochemical process into the electrode volume, the value of which is determined by the ratio of the conductivity of electrolyte and charge transfer resistance (equation).

We studied the effect of the conductivity of electrolyte solutions and the surface capacity of sulfur electrodes on the depth of the electrochemical reduction of sulfur (figure). The sulfur electrodes (d=2.85 cm, A=6.38 cm2) used in this study had the following composition: S (99.5%, Acros) - 70% wt., Ketjenblack® EC-600JD (Akzo Nobel) - 10% wt., Polyethylene oxide (ММ=4x106, Aldrich) - 20% wt. The negative electrodes (d=2.55 cm, A=5.10 cm2) were made of lithium foil (99.9%, Russia) with a thickness of 120 micrometers. 1M solution of LiSO3CF3 in sulfolane (specific conductivity is 0.87 mS/cm at 30 0C) and 1M solution of LiClO4 in sulfolane (specific conductivity is 2.23 mS/cm at 30 0C) were used as electrolytes. The content of electrolytes into lithium-sulfur cells was 4 microliters per 1 mAh, which is equivalent to 6.7 microliters per 1 mg of sulfur. The electrolyte was introduced into lithium-sulfur cells using a “MICROLITERTM Syringe” (Hamilton Company, USA) with a volume of 50 microliters. The accuracy of electrolyte dosing into the cells was ±5 %.

It was established that the penetration depth of the reactions of electrochemical reduction of sulfur and lithium polysulfides into volume of the sulfur electrode is higher in 1M solution of LiClO4 in sulfolane than 1M solution of LiSO3CF3 in sulfolane. The observed patterns are explained from the standpoint of the theory of a porous electrode.

This work was performed as part Government Order of the Ministry of Science and Higher Education of the Russian Federation (theme No. АААА-А17-117011910031-7) and was also financially supported by Russian Science Foundation (Project No 17-73-20115) and by Russian Foundation for Basic Research (Project No 16-29-06190).

Figure 1
Superior Lithium/Potassium Storage Capability of Nitrogen-Rich Porous Carbon Nanosheets Derived from Petroleum Coke
Authors: Li Peng , Sun Yang-Kook
Published: February 2020

Tremendous attention has been paid to carbon-based anodes for lithium-ion and potassium-ion batteries. Nevertheless, conferring high energy storage properties using carbon-based anodes is still challenging. In this work, petroleum coke-based nitrogen-doped porous carbon nanosheets (N-PCSs) were prepared using carbon nitride (g-C3N4) as both a template and nitrogen source and tested as advanced anode materials. The as-obtained N-PCSs constructed through an in situ solid-state approach take advantage of both the high capacity and excellent cycling stability. High capacities were obtained for Li-ion and K-ion batteries (407 mAh g-1 after 500 cycles at 3720 mA g-1 and 206 mAh g-1 after 300 cycles at 1000 mA g-1, respectively); these are some of the best capacities for carbon-based electrode materials and could be ascribed to the unique microstructure of the anodes, i.e., nanosheet morphology, developed porosity, ultrahigh nitrogen doping, and high level of disorder. Meanwhile, this study provides a milestone for high-valued utilization of petroleum coke and other kinds of heavy oil.

References:

1. J.-H. Lee, C.-S. Yoon, J.-Y. Hwang, S.-J. Kim, F. Maglia, P. Lamp, S.-T Myung and Y.-K. Sun, Energy Environ. Sci. 2016, 9, 2152.

2. K. Share, A. P. Cohn, R. Carter, B. Rogers and C. L. Pint, ACS Nano, 2016, 10, 9738.

3. M.-G. Jeong, H. L. Du, M. Islam, J.-K. Lee, Y.-K. Sun and H.-G. Jung, Nano Lett. 2017, 17, 5600.

Figure 1
Evaluation of Tailored Phenothiazines for Overcharge Protection and Cathode Passivation in High Voltage Lithium-Ion Batteries
Authors: Odom Susan A. , Johnson Christopher S. , Li Yingjie , Liang Zhiming , Suduwella T. Malsha , Attanayake N. Harsha , Kaur Aman Preet
Published: February 2020

Redox-active organic compounds are added to lithium-ion battery electrolytes (i) to serve as redox shuttles to mitigate excess current during overcharge and (ii) to passivate electrode surfaces to stabilize interfaces that would otherwise lead to electrolyte decomposition. Especially when expanding the voltage range in charging of lithium-ion cells, overcharge protection efficacy of reported redox shuttles has been limited, yet this may not be a challenge if redox shuttle failure results in cathode passivation, which becomes more critical to cell longevity in higher voltage cells. In this study, we explored a series of phenothiazine-based electrolyte additives with oxidation potentials above 4 V vs. Li in high-voltage (e.g. NMC cathode-containing) lithium-ion cells. Using electrochemical and spectroscopic techniques, we sought to determine if these additives act in shuttling (reversible) or passivating (irreversible) mechanisms.
Understanding Criteria of Cross-Linking Polymer As Effective Binder for Si-Based Lithium-Ion Battery Anodes
Authors: Wang Shuo , Lei Jiafeng , Duan Qiaohui , Yu Denis Y.W.
Published: February 2020

Silicon is a promising anode material for lithium-ion battery because of its high theoretical capacity of 3500 mAh g-1 (formation of Li15Si4) and low operating potential (0.4 V vs Li/Li+) against lithium. However, particle cracking and electrode delamination induced by the large volume change during lithiation and delithiation degrade the cycle performance significantly. Binder in the electrode thus plays an important role in holding the active materials and carbon together. So far, polymers such as alginate and polyimide have been most commonly studied as alternative binder for Si electrodes. While cycle performance is improved, so far there has not been any guiding principles based on the properties of the polymers that can tell a “good” binder from a “bad” one without physically testing it.

In this study, we aim at developing a basic understanding on how the mechanical and chemical properties of binders affect cycle performance of Si-based electrodes. We start with polymers with different functional groups such as polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC) and polyacrylic acid (PAA) and add different amount of borax as cross-linker into the electrodes. By tuning the amount of borax, we can tune the mechanical properties of the binder. We found that amongst the different binder combinations, PAA-borax gives the best electrochemical property in terms of capacity and cycle retention. In addition, the performances are highly dependent on the amount of borax. Figure 1 shows the cycle performance and rate performance of Si electrodes with PAA-borax as the binder. While the capacity fading is significant without borax cross-linker, addition of a small amount of borax improves cycle stability. In particular, we observe that there is an optimal amount of borax of 5% that gives excellent cycle performance. More mechanical characterizations of the electrodes with methods such as in-situ dilatometry and indentation, as well as chemical characterizations such as Fourier Transfer Infrared Spectroscopy (FTIR) are underway to understand the reason for the observed performance, and the results will be shown during the meeting.

Figure 1