bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing Charge Transfer in Solid State Lithium Batteries with Interface Engineering
Authors: Gittleson Forrest S , El Gabaly Farid
Published: February 2020

Solid state lithium-ion batteries promise exceptional reliability, on-chip integration and a better safety profile than those using liquid electrolytes, yet these systems remain costly and generally exhibit inadequate high-power performance. Poor ionic conductivities in solid electrolytes and high charge transfer resistances at electrode-electrolyte interfaces are commonly cited limitations to these cells. Epitaxial modification of electrode-electrolyte interfaces, however, can reduce charge transfer resistances, promoting fast ion exchange between functional components. New insights into interface modification in lithium-ion solid state batteries using pulsed laser deposition (PLD) will be presented including the usefulness of local electrolyte doping and metallic interlayers.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Development of Solid Nanocomposite Polymer Electrolyte to Enable Lithium Metal Anode Safely Cycling for High Energy Battery Application
Authors: Wu James J.
Published: February 2020

NASA’s future missions demand advanced batteries with higher energy density, smaller volume, lighter weight and safer operation. Current state-of-the-art lithium-ion batteries (LIBs) reach the specific energy capacity limits (<250 Wh/kg), which is unable to meet the NASA’s future energy goals (>400 Wh/kg), and also pose safety issues due to using the liquid flammable electrolyte. There are intense on-going developmental activities to increase energy density. Lithium (Li)-metal based battery chemistry has the potential to achieve high-energy goals (>400 Wk/kg) to meet NASA’s future mission’s energy requirements. However, the cycle ability and safety of Li metal as anode are challenging because of morphology change and/or Li dendrite growth.

Solid polymer electrolyte enhances lithium metal-based battery technology by replacing the liquid electrolyte for safety and flexible of design. However, solid polymer electrolyte has problems of low ionic conductivity (<10-3 S/cm) at ambient temperature, and compatibility issues with lithium metal anode, which act as a barrier for the practical application. Solid polymer nanocomposite electrolyte has been developed to help improve ionic conductivity, provide good compatibility with the Li electrode and mitigate the electrolyte/Li metal interfacial issue. It is a promising approach to enhance Li metal-based battery technology. In this presentation, we will present the result of solid polymer nanocomposite electrolyte to enable Li metal anode safe cycling and for high-energy battery application.
Self–Encapsulated Sb/C Nanocomposite with High Capacity and Stability As an Anode Material for Na-Ion Batteries
Authors: Pham Xuan-Manh , Ngo Duc Tung , Park Chan-Jin
Published: February 2020

Li–ion batteries (LIBs) have been studied extensively in the past decades and become one of the most successful energy storage devices, which have rapidly penetrated into our lives. However, due to the limited supply and uneven global distribution of Li resources, the cost of LIBs may increase severely in the near future. Therefore, it is vital to develop more economical alternative energy storage system. In this regard, Na–ion batteries (SIBs) are attractive as promising alternative to LIBs due to the natural abundance of Na resources. Nevertheless, critical obstacles still exist for the commercialization of SIBs due to the lack of appropriate anode materials. Recently, Na-alloy type materials such as Sn and Sb have attracted attention due to their high theoretical specific capacity and low sodiation potential. In particular, Sb-based materials are very attractive as anode materials due to the low and suitable potentials for alloying/dealloying and high theoretical Na–storage capacity (660 mAh g-1) corresponding to formation of Na3Sb phase. However, these Na-alloy type materials can suffer from large volume change and resultant pulverization by the repeated alloying/dealloying processes. Although issues related to poor capacity retention of Na-alloy type materials caused by the large volume change during alloying/dealloying have been addressed using new binders and electrolyte additives, the practical application of Na-alloy type materials in SIBs is still challenge.

 In this study, a self–encapsulated Sb/C nanocomposite as an anode material for SIBs was successfully synthesized using the citric method followed by calcination process in an inert N2 atmosphere. In addition, effect of the content of carbon as a buffer layer on the electrochemical performance of the Sb/C nanocomposite electrode was investigated. The obtained results revealed that the Sb-C nanocomposite with an optimized Sb content of 50.87% exhibited the best electrochemical performance. The electrode showed almost 77.6% capacity retention of 585 mAh g-1 after 300 cycles of charge-discharge at the rate of C/10. Impressively, even at the high rate of 10 C, the specific capacity of 281 mAh g-1
­was maintained. Furthermore, a full cell composed of Sb/C composite anode and NaCoO2 cathode exhibited satisfactory specific capacity and cyclability, which confirms the potential of Sn/C anode for high performance SIBs.
Facile and Mass-Scalable Synthesis of Si@SiC Anode Material for Li Based Rechargeable Batteries
Authors: Ngo Duc Tung , Park Chan-Jin
Published: February 2020

Lithium ion batteries (LIBs) have been considered as a key component for popularizing personal electric devices such as laptops, cell phones and digital cameras, due to the unique properties of LIBs including high power and energy densities, low self-discharge rate and no memory effect. In particular, LIBs enable super-slim smartphones and laptops by providing high energy within extremely limited space. Accordingly, for the last 25 years, LIBs have led us to developing ever-smaller, more powerful and portable electronic devices and being free from being tethered to a grid by wires. However, current LIBs technology faces new challenges of popularizing electric vehicles (EVs), which requires approximately quadruple more energy than that supplied by conventional LIBs to enable 800 km-driving, corresponding to a petrol tank, by EVs. There have been many efforts to improve the energy density of battery, by searching alternative anode and cathode materials which can overcome the limitation of the conventional LIBs. In this work, we propose a simple and reliable method for large-scale synthesis of Si@SiC by magnesium thermal reduction method in which a SiO2@C composite was reduced by magnesium vapor at temperature of 600 oC. By controlling the carbon content in SiO2@C sample we could prepare Si@SiC with various SiC content. Interestingly, the Si@SiC exhibited an outstanding electrochemical performance such as ultra-long cyclability, an excellent rate capability, and high reversible capacity. Furthermore, the full cell fabricated by coupling Si@SiC anode and lithiated-sulfur cathode showed extremely high energy density and power density.
Improved Reversibility of Germanium Oxide Anode Materials
Authors: Jo Changshin , Lee Jinwoo
Published: February 2020

As an anode material, germanium dioxide (GeO2) has a high theoretical capacity of 2152 mAh/g, considering its sequential conversion and alloying reactions. However, the development of stable GeO2 anodes has been hindered by a large volume change during Li-ion insertion/extraction and irreversible conversion reaction of GeO2 from Ge metal state. In this presentation, we present the synthesis of nanoporous composite materials (m-GeO2, m-GeO2-C and m-Ge-GeO2-C) with large mesopore size, developed by a block copolymer (BCP) directed self-assembly approach. Among the samples, m-Ge-GeO2-C exhibited greatly improved reversible capacity (1631 mAh/g), high coulombic efficiency, and stable cycle-life, compared with the other control electrodes. The enhanced performance is attributed by the highly improved conversion reaction due to the synergistic effects of the nanoporous (buffer volume for relieving the structural stress) and the composite structures (enhanced reversibility). The direct evidence for reversible conversion reaction of GeO2 are studied by electrochemical evaluation, ex-situ X-ray diffraction (XRD), and in-situ X-ray absorption spectroscopy (XAS). We show that the tailoring nanostructures and composition of GeO2 can significantly enhance their electrochemical performance.
The Manufacturing of Si-Based Alloy Anodes for Li-Ion Batteries by Mechanical Ball Milling Process
Authors: Hong Soon Ho , Chu Yeon-Yi , Lee Ki Kang , Park Hyun Ki
Published: February 2020

Si-based alloy powders were studied as anode material for Li-ion battery (LIB). The Si-based alloy powders were manufactured by mechanical ball milling process. The ball milled Si-based alloy powders were incorporated graphite as a bufferring matrix to depress the volumetric change of an alloy electrode. We investigated structural and electorchemical properties of the Si-based alloy anodes. Consequently, we obtained good results having an excellent coloumbic efficiency of 85%. Also, we found not only a large initial capacity of 620mAh/g but also a high capacity retention of 90% at the 100th cycle.
A Highly Concentrated Ether Electrolyte for Efficient Na-Ion Half Cells
Authors: Schafzahl Lukas , Hanzu Ilie , Wilkening Martin , Freunberger Stefan A
Published: February 2020

Na-ion batteries are amongst the most appealing alternatives to Li-ion batteries due to a similar intercalation chemistry and lower cost. Novel Na-ion chemistries are often assessed in half cells that contain Na-metal counter and reference electrodes (Figure 1). These electrodes are highly reactive and require a passivation layer to work, which is formed from electrolyte decomposition products. Recently, however, the passivation layer of standard carbonate electrolytes on sodium metal was found to be rather instable, raising questions about the reliability of both Na-ion half cells and other low voltage anodes.[1]

This work presents a dimethoxyethane (DME) / sodium bis(fluorosulfonyl)imide (NaFSI) (2/1 (n/n)) electrolyte that forms a stable and resilient passivation layer on sodium metal, as indicated by highly reversible sodium plating/stripping. Further investigation of the passivation layers by post-mortem FTIR and 1H-NMR analysis reveals that conventional organic carbonate based electrolytes decompose to organic salts such as sodium ethyl dicarbonate. In contrast, the DME/NaFSI electrolyte forms ethereal and alkoxide species as well as inorganic salts derived from the FSI anion. These compounds ensure sodium metal passivation and thereby enable more reliable and efficient testing in Na-ion half cells.

[1] Iermakova, D. I.; Dugas, R.; Palacin, M.R.; Ponrouch, A. J. Electrochem. Soc. 2015, 162, A7060-A7066

Figure 1: A typical half-cell setup for testing a novel electrode material in a Na-ion cell

Figure 1
Reversibility of Brominated Carbon Electrodes for Lithium-Bromide Battery Applications
Authors: Peterson Benjamin B. , Flake John
Published: February 2020

Lithium-ion batteries provide, on average, a near 150 Wh/kg energy density and capacity near 170 mAh/g [1]. Other lithium energy storage chemistries such as lithium-air and lithium-sulfur have been proposed as potential higher energy (11680[2], 2500[3]  Wh/kg) capacity alternatives; however, various issues plague these battery types, ultimately affecting the energy and performance. Lithium-air batteries suffer from poor cyclability (~60-70% efficiency) and materials issues stemming from moisture and poor separation of environmental contaminants[2]. Lithium-sulfur suffer from capacity fading (>10% over 100 cycles) and loss of active material due to polysulfide dissolution[5]. Recently, studies using a lithium-bromide chemistry have shown promising results as a rechargeable alternative to lithium-ion batteries, including energy densities of 1220 Wh/kg[6] and efficiencies between 90%[7] and 99.5%[8].

In order to investigate the viability of rechargeable lithium-bromide batteries, studies were conducted with graphite and brominated electrodes in an electrolyte utilizing the highly soluble Br3
-/Br- redox couple. Characterization of the electrodes and brominated particles were completed using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), and Transmission Electron Microscopy (TEM). From electrochemical experiments, Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), the electrodes display behaviors consistent with pseudo-batteries, containing both capacitive and faradaic responses; additionally, higher activity (up to 2x the current density of untreated graphite) is seen with the brominated electrodes. The results of these analyses will be presented, and the implications for rechargeable lithium-bromide batteries will be discussed.

References

1. B. Scrosati and J. Garche, Journal of Power Sources,
195, 2419-2430 (2010).

2. G. Girishkumar, et. al., Journal of Physical Chemistry Letters,
1, 2193-2203 (2010).

3. L. Chen and L.L. Shaw, Journal of Power Sources,
267, 770-783 (2014).

4. P. Leung, et. al., RSC Advances,
2, 10125-10156 (2012).

5. A. Manthiram, Y. Fu, and Y-S. Su, Accounts of Chemical Research,
46 (5), 1125-1134 (2013).

6. Z. Chang, et. al., Journal of Materials Chemistry A,
2, 19444-19450 (2014).

7. Y. L. Wang, et. al., Journal of Materials Chemistry A, 3, 1879-1883 (2015).

8. K. Takemoto and H. Yamada, Journal of Power Sources,
281, 334-340 (2015).

Figure 1:

Figure 1
Electrochemical Properties of Nickel Oxide Nanoplates As Electrode for Lithium Ion Battery
Authors: Adkins Joshua W. , Arnold Corey , Meda Lamartine
Published: February 2020

Nanostructure transition metal oxides (MO-type M = Fe, Co, Ni, Cu, . . . ) with rock-salt structure are promising anode materials for lithium ion batteries. These types of materials can store two to three times the capacity of graphite anode (372 mAh g-1) which is the state-of-the-art technology. Here we focus on the growth of Nickel oxide (NiO) prepared by chemical vapor deposition (CVD) directly on current collectors and understanding of the origin of the excess capacity. The synthesis of the NiO nanoplates by CVD directly on the current collectors is ideal for studying the electrochemical properties because they are no interferences from additives. In addition, the direct growth of the materials onto current collectors provides faster mass and electron transport due to the improvement in conductivity across the interfaces and through the materials due to its nanosize. The microstructural characteristics of the as-prepared NiO nanoplates were examined by high resolution transmission electron microscopy which showed that they were arranged randomly on the current collector. Selected area electron diffraction showed that the NiO is polycrystalline with the face-centered cubic crystal structure. The X-ray photoelectron spectroscopy showed that the as-prepared materials are pure NiO. We studied the galvanostatic discharge-charge of the NiO electrode. During the first discharge process from 3.0 V to 0.1 V, a plateau at approximately 0.70 V followed by a gradual decrease to 0.1 V, is observed. This is due to the reduction of Ni2+ to Ni0 and the formation of Li containing organic and solid electrolyte interface (SEI). The first discharge corresponds to approximately 1100 mAh/g which is equivalent to 3 mol of Li per mol of NiO which is more than the expected capacity of according to the conversion reaction: NiIIO + Li0 +2e- ß à LiI
2O + Ni0 (718 mAh/g). The excess capacity of the NiO nanoplates and the cyclic voltammetry will be discussed.
In Situ Multiscale Investigation of Reaction Pathways in a Sulfide Material for Sodium and Lithium Batteries
Authors: Boebinger Matthew G , Xu Michael , McDowell Matthew T
Published: February 2020

Sodium-ion batteries are attractive due to their potentially lower cost than lithium-ion systems. However, the larger ionic radius of Na+ means that candidate electrode materials often undergo more substantial volumetric changes during reaction when compared to Li-ion batteries, and these changes must be understood and controlled for the development of electrode materials with long cycle life. In this study, multiple in situ techniques are used to investigate nanoscale-to-macroscale transformation pathways in Cu2S (a sulfide electrode material) during electrochemical reaction with Na and Li. In situ and ex situ x-ray diffraction reveal that the macroscale phase transformations in Cu2S electrodes are similar within both Na and Li cells; the material undergoes initial intercalation followed by conversion in both cases. However, in situ transmission electron microscopy (TEM) shows that the nanoscale reaction pathways differ significantly. During sodiation, Cu2S particles undergo a local phase separation that results in Cu nanocrystals surrounding a shell of Na2S. This leads to complete destruction of the initial Cu2S lattice, as opposed to the retention of the lattice during the displacement reaction in the lithiation case. These different reaction mechanisms likely contribute to observed differences in electrochemical signatures in Na and Li cells. Despite these dissimilarities, Na/Cu2S electrochemical cells are shown to exhibit excellent cycle life (negligible capacity decay over 400 cycles), which is similar to the Li case. Thus, although the more substantial volume changes during the sodiation of Cu2S induce a new reaction pathway, they do not cause accelerated capacity decay, as is commonly argued for Na-ion materials. These results suggest that other large-volume-change electrode materials may also be engineered for long cycle life in next-generation Na-ion batteries.

Figure 1
Titanium Oxide Filled Carbon Fibres for Lihium and Sodium Ion Insertion
Authors: Čech Ondřej , Vanýsek Petr , Chladil Ladislav , Částková Klára
Published: February 2020

In this contribution, we would like to present structural and electrochemical characterization of composite carbon/TiO2 fibers prepared by centrifugal force spinning. Monoclinic TiO2-B is a very promising material with respect to lithium-ion insertion and unlike other TiO2 allotropes, TiO2-B crystallizes in monoclinic lattice with opened layered structure giving it extraordinary possibilities for lithium ion storage. Carbon fibers filled with TiO2 particles were prepared using PAN as carbon source together with the mixture of sodium trititanate Na2Ti3O7 and sodium hexatitanate Na2Ti6O13 as TiO2 source. The solution for preparation of fibers was made by dissolving PAN in DMF with dispersed hydrothermally synthesized Na2Ti3O7/Na2Ti6O13 nanorods. Fiberio Cyclone 1000M/D was used to spin the as prepared solution in the form of composite polymer/ceramic fibers which were heat treated in nitrogen atmosphere at 800°C subsequently. XRD measurements revealed that the sodium titanates were successfully transformed in the form of TiO2 with either monoclinic or tetragonal lattice. Electrochemical measurements were performed in aprotic electrolyte against metallic lithium in a three electrode setup. Cyclic voltammetry shows response typical for mixture of two crystallographic phases of TiO2 where TiO2-B is present.

Figure 1
Influence of Yttrium Doping on the Structural and Electrochemical Performances of LiNi0.5Mn1.5O4 Spinel in Half-Cell and Full-Cell
Authors: Wang Li , Wu Wei , Wang Jiangfeng , Qin Xing , Guo Jianling
Published: February 2020

Pristine and yttrium-doped LiNi0.5-x
Y
x
Mn1.5O4 spinel powders (x=0, 0.005, 0.01, 0.02, 0.04) were synthesized by a facile solid-state method. The effect of yttrium doping content on the electrochemical properties of LiNi0.5-x
Y
x
Mn1.5O4 was investigated by using half-cells paired with lithium metal and full-cells paired with graphite. XRD and FT-IR analysis shows that the cation disordering degree (Mn3+ content) first increase (x≤0.02) and then decrease with Y doping content and the Y doping can effectively inhibit the formation of Li
x
Ni1-x
O impurity phase. Electrochemical results show that in half-cells, appropriate Y doping (x=0.01) exhibits optimal rate capability and cycling stability of LiNi0.5Mn1.5O4 cathode material, due to higher phase purity, enlarged lattice parameter, higher disordering degree, higher structural stability by introducing Y-O bond, lower charge transfer resistance and higher lithium ion diffusion coefficient, although the 0.2 C discharge capacity is slightly lower than pristine LiNi0.5Mn1.5O4. However, in full-cells, the yttrium doping effect on the improvement of battery performance is not obvious as half-cells.
The Electrochemical Properties of Hydrothermally Self-Assembled 3D Rgo for Lithium Air Batteries
Authors: Choi Yusong , Kim Jiyoun , Jang Yoonhee , Yoo Hyeryun , Cho Janghyeon , Seo Ilsung
Published: February 2020

The oxygen electrode is the most important part in lithium air batteries for oxygen reduction and evolution reaction (ORR/OER) in order to get closer to the theoretical energy density of 11,238 Wh/kg, which is the best among the batteries ever developed. Many carbon materials have been researched as a candidate oxygen electrode for lithium air batteries such as a carbon black, CNTs and 2D graphene. Compared to the many research results, there are still many controversies on optimum oxygen electrode for lithium air batteries. The most important properties for oxygen electrode are the microstructures such as an optimum pore size of less than 10 nm and pore size distributions which affect greatly to ORR/OER at the interface of between the electrode and electrolyte.

 In this perspective, the hydrothermally self-assembled 3D RGO has great potential as an oxygen electrode. Because, it has a wide range of pore size and large surface area, as well as a high conductive network. However, 3D RGO has some obstacle to be surpassed such as side reactions which induce a large voltage gap, and decay the cycling performances. If the electrochemical reaction mechanisms of 3D RGO in lithium air batteries are well investigated clearly, the 3D RGO is a still desirable electrode for lithium air batteries. In this research, we synthesized self-assembled 3D RGO electrode by means of hydrothermal methods. The electrochemical properties and reaction mechanisms of the self assembled 3D RGO electrode were investigated using BET, EIS, SEM, XRD. As a result, we carefully assessed the possibility of 3D RGO as a game changer in lithium air batteries.
Optoelectronic and Electrochemical Properties of ZnO Based Films
Authors: Shi Qian , Lin Song sheng , Hou Hui Jun , Wei Chun bei , Li Hong , Su Yi fang , Hu Fang
Published: February 2020

ZnO based thin films are commonly used as transparent conductive oxides (TCO). There is increasing attention paid to improving transparent conductive electrodes for applications in photovoltaic devices, displays and electronics. However, simple deposition technology with better properties than the present generation are required for new devices. In this study, ZnO based TCO films with different dopants were prepared by magnetron sputtering technique at room temperature. A relationship between the microstructure and optoelectronic properties of sputtered ZnO based films was studied.

As a potential transparent anode electrode for thin film batteries, the electrochemical behavior were further investigated. The electrochemical test show that the highest capacity of 300 mAh/g was obtained, which is higher than that of traditional graphite anode. In comparison with the resistivity results, the conductivity shows a positive effect in enhancing the specific capacity. High conductivity will provide more chance for the reaction between Li and active materials. The cycling test shows that a reversible capacity of 150 mAh/g can be achieved even after 200 cycles. The research reveals that ZnO based films with low electrical resistance are in favour of their electrochemical performance.
Preparation of Hollow Hithium Titanate Fiber Tube By Electrospinning
Authors: Wang Yudong , Gao Fei , Liu Hao , Zhang Mingjie , Geng Mengmeng , Yang Kai
Published: February 2020

With the progress of science and technology, notebook computers, microcomputers, digital cameras, mobile phones and other new electronic equipment come out one after the other. The development of new products to the storage of energy have a greater demand, the traditional graphite anode material has been unable to meet its performance needs. The spinel lithium titanate is a lithium ion battery anode material with good cycling capability, wide operating temperature range and good safety performance. However, due to the poor electrical conductivity and low lithium-ion diffusion coefficient, the rate performance is very limited. Therefore, increasing rate performance of lithium titanate anode material becomes the only way of application of lithium titanate .

In this paper, lithium titanate is prepared by coaxial electrospinning. With the High molecular weight polymer polyvinylpyrrolidone (PVP) providing high viscosity，a solution spinning solution of PVP and absolute ethanol is used as the inner layer template solution. The Part of solution with a lithium source and a titanium source set as an outer layer precursor solution. After the titanate precursor fiber filaments are calcined, with core and outer PVP are removed the hollow lithium titanate filament is finally obtained. Figure a is cycle-capacity curve of the hollow lithium titanate anode material after prepared into a button cell. The first 0.2C rate of the specific capacity is 174.9mAhg-1 with theoretical specific capacity flat, and at the 30C specific capacity can be to 105 mAhg-1, which can achieve that Li-ion battery immediately charge. Figure b shows that, at low charge and discharge rate, lithium titanate discharge platform is relatively stable, while platform stability is poor at the high charge and discharge rate.

Figure 1. (a) Discharge capacity curves of lithium titanate at different charge and discharge rate; (b) the first discharge profiles of lithium titanate at the different charge and discharge rate.

Reference

[1] Cho, Y., Lee, S., Lee, Y., Hong, T., & Cho, J. (2011). Spinel-layered core-shell cathode materials for li-ion batteries. Advanced Energy Materials,1(5), 821–828.

[2] A. K. Moghe, & Professor B. S. Gupta. (2008). Co‐axial electrospinning for nanofiber structures: preparation and applications. Polymer Reviews,48(2), 353-377.

[3] Tong, H., Tao, X., Wu, D., Zhang, X., Li, D., & Zhang, L. (2014). Preparation and characterization of doped tio 2, nanofibers by coaxial electrospining combined with sol–gel process. Journal of Alloys & Compounds, 586(10), 274-278.

Acknowledgment

Thanks for being funded by the Technology Research Program of the State Grid about Preparing Submicron Lithium Titanate-based Materials for Energy Storage Batteries (DG71-15-042) .

Figure 1
Effects of Sintering Temperature and Cathode Composition on Al2O3 Coatings of Lithium-Ion Cathodes
Authors: Han Binghong , Peebles Cameron , Penkauskas Tadas , Vaughey John T. , Dogan Fulya
Published: February 2020

Al2O3 coatings on cathode materials are thought to be an effective way to prevent chemical and structural evolutions during battery operation and therefore to improve the cyclability of lithium-ion batteries. However, the systematic study on the effect of coating process and cathode composition on interfacial morphology and composition and their effect on electrochemical performance is missing. In this work, we used a wet-chemical method to synthesize a series of Al2O3-coated LiNi0.5Co0.2Mn0.3O2 (NCM523) and LiCoO2 (LCO) treated under various sintering conditions. Using nuclear magnetic resonance and electron microscopy we have shown that the homogeneity, morphology and atomic structures of the coating layers are highly depended on the post heating temperature, and schemes of surface coating layer evolution are built upon a comprehensive study on aluminum local order, coating-bulk interactions and imaging characterizations. For Al2O3-coated NCM523, higher annealing temperature leads to more homogeneous and more closely attached coating on cathode materials, corresponding to better electrochemical performance. While for Al2O3-coated LCO, the incorporation of Al into the cathode materials can be observed after treated under high temperatures, which is not observed on Al2O3-coated NCM523. As a result, the Al2O3-coated LCO annealed at the higher temperature shows higher initial capacity and worse cyclability compared to that annealed at the lower temperature, due to the total intercalation of surface alumina into the bulk layered structure. This work shows that the chemical compositions of cathode materials and annealing conditions have significant influence on the nature of Al2O3 coating layers and to the electrochemical performance of Al2O3-coated cathode materials.
Anthraquinone Functionalized Reduced Graphene Oxide As Electrode Material for Aqueous and Non-Aqueous Rechargeable Batteries
Authors: Esat Burak , Bahceci-Sertkol Sumeyye , Momchilov Anton Angelov
Published: February 2020

The use of electro-active organic compounds as electrode materials in rechargeable batteries has been a very active research topic due to their high theoretical capacity, availability of various redox potentials depending on the electro-active group, ease of modification of properties, and improved safety. However, the issue of solubility in electrolytes limits their applications in batteries. The most common solutions for this problem involve incorporation of these organic molecules into the insoluble polymeric structures and trapping of these inside porous carbon materials. Here, we have demonstrated the covalent attachment of anthraquinone (AQ) derivatives via nitrene chemistry onto reduced graphene oxide (RGO) as another alternative. The successful synthesis of the RGO functionalized with anthraquinone groups (RGO-AQ) and its utilization as cathode materials in Li-batteries have also been demonstrated. The cells with RGO-AQ used as cathode materials initially discharged 126 mAh/g when cycled between 1.8-3.2V at the rate of 5.35mA/g in LiPF6/ EC:DEC (1:1) electrolyte, and discharged 185.7 mAh/g when cycled between 1.3-3.6V against Li metal at the rate of 6.0 mA/g in LiClO4/ PC electrolyte. The AQ-RGO has been used also as an anode material against in an aqueous battery against NiOOH (AQ-rGO | 30% NaOH | NiOOH). This battery provided a capacity of 140 mA/h at 0.83V and displayed a very good rate capability.

Figure 1
Characterization of Suspensions of Lithium-Ion Battery Active Materials
Authors: Koenig Gary , Qi Zhaoxiang
Published: February 2020

A variety of properties are used to characterize lithium-ion battery active materials when synthesizing a new material in the lab or controlling the quality in a manufacturing product line. Rate capability is one of these measured properties and is important because many applications need good high rate performance, for example plug-in hybrid electric vehicles. Rate capability tests are time and material intensive because they require electrode fabrication, cell fabrication, and cell cycling, and this entire process can take up to a couple of weeks. In addition, properties derived from coin cell cycling are not just dependent on the active material properties but also can be dependent on other electrode components and the electrode microstructure. In this talk, we will describe recent efforts to characterize suspensions of lithium-ion battery active materials. The electrochemical evaluation is relatively fast, under 30 minutes, and characterizes the active material particles in the electrolyte without the complicating factors of conductive additives, binders, and resulting electrode microstructures. The particles colliding with a current collector result in a single measured resistance, and in this talk we will demonstrate proof-of-concept that this resistance can correlate to the relative rate capability between active materials. Current limitations of the technique will also be described.
A Comprehensive Understanding on How Ultrathin Coating Layers on Active Particles Enhance Battery Performance Significantly
Authors: Sarkar Susmita , Patel Rajankumar L. , Liang Xinhua , Park Jonghyun
Published: February 2020

The Atomic Layer Deposition (ALD) coating strategy on active materials of Li-ion battery is known as an effective way than other coating techniques to enhance battery performance, but there is still substantial uncertainty about how these coating layers are the origin of the enhanced performance. A comprehensive model is developed based on experimental measurements and theoretical analysis to study how different coating strategies affect the mechanical and electrochemical responses of a battery system. Although it appears that a thicker coating helps to provide higher capacity and cycle life improvement, but a too-thick layer may act as a migration barriers and facilitate much slower lithium transport, resulting in capacity decrease. Further, the developed model quantitatively predicts the capacity retention of coated particles by mitigating the transition metal ion dissolution, which is one critical capacity fade mechanism of the metal oxide cathode materials. This quantitative study reveals the trade-off mechanism of ALD coating between the species transport (capacity) and protection (lifetime), which could be an important guidance for thin-coating based strategies for battery performance enhancement.
A Binder Free and High Sulfur Loaded Three-Dimensional Carbon Nanotubes Electrode for High Performance Li-S Batteries
Authors: Patel Mumukshu D. , Cha Eunho , Kang Chiwon , Choi Wonbong
Published: February 2020

Rechargeable Li-S batteries represent advanced battery system offering high energy density with low cost and environmentally benign electrochemical energy storage compared to currently available Li-ion batteries. The critical limitations are mainly associated with the insulating nature of sulfur (5 x 10-30 S/m), and formation and dissolution of intermediate polysulfides (Li2Sx; 2<x<8) into the electrolyte during charge/discharge processes resulting in capacity fading and low cycling stability. Most of the previous strategies reported in literature suggested for entrapment of polysulfides considered the areal density of the sulfur in the cathode to be less than 2mg/cm2. However, in order to obtain superior electrochemical performance (high volumetric and gravimetric energy density) compared to currently available state-of-the art Li-ion batteries, the sulfur loading amount has to be incremented substantially, increasing the sulfur weight percentage in the cathode electrode, and optimize with the electrolyte (µL)/sulfur (mg) ratio for maximum electrochemical performance. Here in, we develop a simple and facile binder free approach without the use of any complex chemical routes (use of carbon black, PVDF, and NMP) to impregnate different S loading amount into micro-channeled conducting framework of three dimensional carbon nanotubes (3D CNTs). It also provides effective utilization of sulfur particles, high electrolyte absorbability facilitating well-localized polysulfides within the electrode structure, and maintaining good structural integrity during volume expansion. The proposed strategy delivered a specific capacity of ~1285mAh/g at 0.5C rate (1.55mA/cm2) and excellent rate capability for all different loading amounts. Furthermore, in this presentation the detailed synthesis for higher loading amount of sulfur and their superior electrochemical performance with unique physical and electrochemical properties will be discussed in detail.
Study of Polysulfide Speciation in Lithium Sulfur Batteries Using in Situ Confocal Raman Microscopy
Authors: McBrayer Josefine , Beechem Thomas E. , Perdue Brian Robert , Garzon Fernando H , Apblett Christopher A.
Published: February 2020

Lithium sulfur (Li-S) batteries are a promising option for high energy density applications, such as electric vehicles and grid storage. In addition to a high theoretical specific energy, the Li-S system also boasts a lower cost and the use of relatively nontoxic, abundant materials compared to current lithium ion batteries. However, soluble, mobile polysulfide intermediates in the electrolyte lead to a polysulfide shuttling mechanism resulting in damage to the anode, loss of active material, and diminished cyclability. A better understanding of the polysulfide speciation as a function of depth of discharge is warranted to identify means to mitigate the polysulfide shuttle.

In response, polysulfide speciation is examined, under relevant conditions, in an operational coin cell, at varying states of charge and position, using in situ confocal Raman microscopy. Specifically, a spectroscopic 2032 coin cell was designed for use in in situ experiments while maintaining a representative environment for discharge. The coin cell consisted of a carbon-sulfur cathode, lithium metal anode, and 1:1 1,2-dimethoxyethane to 1,3-dioxolane with 1M LiTFSI and 0.25M LiNO3electrolyte. To aid in comparison, polysulfide standards were synthesized and investigated using electrospray ionization-mass spectroscopy (ESI-MS). Raman and ESI-MS were utilized to map polysulfide speciation and relative abundances along the discharge curve. The electrolyte within the cell was probed as a function of position within the cell to determine the spatial distribution of differing polysulfide species. Challenges associated with performing Raman spectroscopy within this environment, to differentiate the varying polysulfide species in solution, were also investigated.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

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Enhanced Performance of Lithium-Ion Batteries By Atomic Layer Deposition Thin Film Coating
Authors: Liang Xinhua
Published: February 2020

Thin film coatings on lithium-ion battery (LIB) electrode materials have proven to be an effective way to improve the capacity retention, rate capability, and thermal stability of electrode materials. Atomic layer deposition (ALD) is a layer-by-layer thin film coating technique. It consists of a set of sequential reactions that occur only between the gaseous precursors administered to the reactor, and the functional groups present on the surfaces of primary particles. ALD is believed to be an important technique for LIB applications. Currently, most of ALD-LIB research focuses on insulating ALD materials. There is a trade-off between the species transport (increasing capacity) and protection of the particles (expecting long cycle life) using insulating materials. We reported a breakthrough to overcome this trade-off by coating an ultra-thin conformal cerium dioxide (CeO2) film on the surfaces of LiMn2O4 particles. The optimized CeO2 film (~3 nm) coated particles exhibited a significant improvement in capacity and cycling performance compared to uncoated, Al2O3 ALD coated, and ZrO2 ALD coated samples at room temperature and 55 °C for long cycling numbers. The initial capacity of the 3 nm CeO2 coated sample showed 24% increment compared to the capacity of the uncoated one, and 96% and 95% of the initial capacity was retained after 1,000 cycles with 1 C rate at room temperature and 55 °C, respectively. Iron oxide films were coated on LiMn1.5Ni0.5O4 particles by ALD for the synergetic effect of performance enhancing by iron doping and conformal iron oxide film coating. With an optimal film thickness of ~0.6 nm, the initial capacity improved by 25% at room temperature and by ~26% at 55 °C at 1C cycling rate. The synergy of doping of LiMn1.5Ni0.5O4 with Fe near surface combined with the conductive and protective nature of the optimal iron oxide film led to high capacity retention (~93% at room temperature and ~91% at 55 °C) even after 1,000 cycles at 1C cycling rate. This work has the potential to produce the foundational knowledge necessary to solve the “capacity-protection” dilemma.
Approaching in-Situ Investigation of SEI Growth Dynamics By Isotope-Assisted TOF-SIMS
Authors: Lu Peng , Liu Zhe , Zhang Qinglin , Xiao Xingcheng , Chen Long-Qing
Published: February 2020

Among the many challenges for Li-ion batteries (LIBs) to achieve long cycle life, formation of high quality solid electrolyte interphase (SEI) is of critical importance. SEI forms on LIB anode during the initial cycles, and its properties directly impact battery life and power performance. In-depth understanding of SEI growth mechanism can provide critical parameter input for modeling and simulation, set foundation for the SEI properties and performance correlation, and lead to the ultimate effective artificial SEI or coating design to achieve satisfactory cell cycle efficiency. However, due to the nm thickness and air/moisture sensitivity of SEI, designing and performing in-situ diagnostics are technically challenging. To date, most studies on SEI properties are performed on electrodes harvested after SEI formation, and the time-dependent growth mechanism of SEI during its formation remains to be elucidated.

In this talk, we will present an approximation of in-situ diagnostic method, by utilizing isotope-assisted time-of-flight secondary ion mass spectrometry (TOF-SIMS). This method is capable of obtaining time-dependent information during SEI growth, even after the growth process has completed. The model battery design includes a Cu electrode, 6Li labeled electrolyte (1M 6LiBF4 in EC:DEC 1:2) and a 7Li metal counter electrode. As SEI grows on the Cu electrode, the 6Li:7Li isotope ratio in the electrolyte decreases due to 6LiBF4 consumption. The time scale of SEI growth thus can be represented by the 6Li:7Li ratio in the SEI, and each 6Li:7Li ratio corresponds to a snapshot during SEI growth. The isotope ratio are measured with TOF-SIMS after harvesting the SEI. With this method, we have found that the SEI portion formed first (higher 6Li:7Li ratio) presents at the electrolyte/SEI interface, and the SEI formed last (lower 6Li:7Li ratio) exists at the SEI/electrode interface. These results also indicate that new SEI forms at the SEI/electrode interface. Further chemistry analyses with TOF-SIMS and XPS show that the portion formed first are mostly organic compounds while the portion formed last are mostly inorganic compounds. This method could also be applied in other fields where growth dynamics are of interest, such as investigating Li dendrite growth.

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3D Conductive Network with High Loading Li2s for High Performance Lithium-Sulfur Batteries
Authors: Wang Dong-huang , Tu Jiangping
Published: February 2020

Nowadays, lithium-sulfur (Li-S) batteries have been considered as one of the most promising next-generation rechargeable batteries, owing to their high theoretical specific capacity of 1672 mAh g−1, high energy density of 2600 Wh kg−1, low-cost and abundant resources. However, the commercial application of Li-S batteries is still hindered by several problems, including insulativity of element sulfur, dissolution of polysulfides and large volume expansion. In addition, sulfur cathodes need be paired with metallic lithium, which tends to form dendrites on the anode surface during cycling resulting in safety problems. Therefore, fully lithiated state of sulfur-lithium sulfide (Li2S) is advantageous over sulfur, because it can paired with metal-free anodes (e.g. graphite, silicon and Sn) avoiding safety problems. In addition, Li2S shows a high theoretical specific capacity of 1166 mAh g−1 and a high melting point of 938°C. Moreover, when Li2S convers to S companying with volume shrinkage, which will not only creates enough space for volumetric expansion but also makes the structure more stable. However, similar to sulfur cathode, low conductivity of Li2S, low active material loading and polysulfide dissolution Li2S limit application of Li2S for high performance batteries. Consequently, it is important to introduce Li2S into three dimensional conductive matrix/host for high performance. Herein, we construct a 3D conductive network with high loading Li2S through a facile liquid solution-evaporation. The 3D conductive network not only possesses a hierarchical architecture with abundant macroporous channels and exhibits a high surface area, which provides enough reaction sites to load and stabilize high-loading Li2S, but also improves the electronic conductivity of Li2S and demonstrates pronounced electrochemical performance with enhanced cycle stability and a good capacity retention.
Encapsulating of Sulfur and Acetylene Black with Manganese Dioxide Nanosheets for High-Performance Lithium–Sulfur Batteries
Authors: Walle Maru Dessie
Published: February 2020

A novel acetylene black (AB) and sulfur composite wrapped by manganese dioxide nanosheets (MnO2@AB/S) as a cathode material for lithium-sulfur (Li-S) batteries was prepared. The MnO2@AB/S composite was first prepared by simple melt-diffusion sulfur on/into AB followed by encapsulating by the two dimensional MnO2 nanosheets. Surface modification on the sulfur and AB composite would be an efficient strategy to enhance the cycle stability and to improve the insulating nature of sulfur. The MnO2 nanosheets also increase high active contact area to improve the conductivity and stability of the cathode. The as-prepared cathode material with a high area sulfur loading of 6.19 mgcm-2 delivers a high initial discharge capacity of 994.4 mA h g-1 and the coulombic efficiency is up to 91.4% at high current rate of 1 C compared with AB/S composite. The MnO2@AB/S electrode is promising as a potential practical application for lithium-sulfur batteries.
Enhancement of Cycling Performance of Li-S Batteries By Redox-Active Anthraquinone-Based Polymers
Authors: Lau Ka-Cheong , Dietz Rago Nancy L. , Connell Justin Grant , Liao Chen , Zhang Zhengcheng
Published: February 2020

Lithium-sulfur batteries are promising alternative to Li-ion batteries owing to high theoretical gravimetric capacity (1675 mAh/g) and low cost of elemental sulfur. However, Li-S batteries suffer from rapid capacity fading largely due to shuttling of various polysulfide intermediates in solution. Here we present our studies on the effect of incorporation of redox-active anthraquinone-based polymers in bulk sulfur cathodes on cycling of Li-S batteries. Through electrochemical characterization and post-test analysis, the role of redox-active polymers in bulk sulfur cathodes is proposed.