bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fast Start-up Stratergy for Biocathode Acclimation in a Hydrogen-Producing Microbial Electrolysis Cell
Authors: Liang Dawei , Liu Yanyan , Peng Sikan , Lu Shanfu , Xiang Yan
Published: February 2020

Abstract not Available.
The Influence of Deposition Potentials on Cu Nanoparticles on Mo Electrodes
Authors: Ren P
Published: February 2020

Abstract not Available.
Keynote Presentation: High Temperature Electrochemical Pathways Towards Low-Carbon Steelmaking and Efficient CO2 Utilization
Authors: Wang Dihua
Published: February 2020

Abstract not Available.
Comparative Studies for the Electrochemical Regeneration of Organic-Saturated Adsorbents: Application for the Treatment of Diluted Solutions
Authors: Bouaziz Ines , Abdelhedi Ridha , Savall André , Groenen Serrano Karine
Published: February 2020

Abstract not Available.
Invited Presentation: NMR and Diffraction Studies of Electrode Reactions: The Effect of Structure, Rate and Electrode Formulations on Reaction Mechanisms
Authors: Grey Clare P. , Liu Hao , Strobridge Fiona , Zhou Lina , Leskes Michal , Hu Yan-Yan
Published: February 2020

A full understanding of the operation of a battery requires that we utilize methods that allow devices or materials to be probed while they are operating (i.e., in-situ). This allows, for example, the transformations of the various cell components to be followed under realistic conditions without having to disassemble and take apart the cell. To this end, the application of new in and ex-situ Nuclear Magnetic Resonance (NMR) and X-ray diffraction (XRD) approaches to correlate structure and dynamics with function in lithium-ion batteries will be described. The in-situ approach allows processes to be captured, which are very difficult to detect directly by ex-situ methods. For example, we can detect side reactions involving the electrolyte and electrode materials and non-equilibrium processes that can occur during extremely fast charging and discharging. Ex-situ NMR investigations allow more detailed structural studies to be performed to correlate local and long-range structure with performance in battery materials.

In this talk, I will describe the use of NMR spectroscopy and X-ray diffraction to probe local structure changes in lithium ion batteries focusing on our work on olivines, spinels and lithium air cathodes. In the olivine work, we show how the use of fast charging allows us to capture metastable/non-equilibrium states. Mapping of the electrodes allows the distribution of the reaction front across the electrode to be followed. Second, the development of new NMR approaches to investigate paramagnetic battery materials, both in and ex situ, will be discussed, the approach making use of both theory and experiment. Although it is difficult to achieve high-resolution spectra from these paramagnetic materials (see for example the Li1.08-xMn1.92O4 resonance in Figure 1) in the in situ experiments, measurements of the relaxation time allow access to the dynamics of the lithium ions in real time as a function of state of charge.

Figure 1: 7Li in situ NMR of Li1.08Mn1.92O4 during galvanostatic cycling (electrochemistry shown on the left). The red arrows indicate the evolution of the resonance from the tetrahedral sites in Li1.08-xMn1.92O4. Short recycle delays are used so as to suppress the resonance from the electrolyte. Note the apparent increase in intensity at the end of the 4.0 V process/beginning of 4.2 V process on charge and the end of the 4.2 V process on discharge. The behaviour originates from a change in spin-spin relaxation behaviour and indicates a slowing down of the cation/electron mobility. This phenomena has been explored as a function of temperature and spinel stoichiometry.
Invited Presentation: Connecting Electronic Structure to Electrode Kinetics of Li-Ion Batteries
Authors: Van der Ven Anton
Published: February 2020

Kinetic processes within the electrodes of Li-ion batteries remain poorly understood. Lithium insertion and removal from electrode materials requires solid-state diffusion at non-dilute concentrations and is often also accompanied by a sequence of diffusional and structural phase transitions. Since these phase transformations happen rapidly at room temperature, they are difficult to characterize experimentally. First-principles statistical mechanical approaches are now capable of predicting key electronic, thermodynamic and kinetic properties of electrode and electrolyte materials. They have been especially useful in elucidating the role of chemistry and crystal structure on ionic mobility as a function of concentration in intercalation compounds. The kinetics of electrode materials becomes even more complex for reaction mechanisms that go beyond intercalation processes, such as displacement and conversion reactions. Non-intercalation reaction mechanisms in general are often accompanied by substantial hysteresis and sluggish rate capabilities. Electrode materials used in energy storage devices are also affected by a strong coupling between chemistry and mechanics. Charging and discharging of electrode materials can produce local stress intensities due to concentration gradients and misfit strain across migrating interfaces. First-principles electronic structure calculations have demonstrated that fracture properties can depend strongly on the local chemistry, making the susceptibility of electrode materials to fracture very sensitive to the state of charge. This talk will describe multi-scale approaches to predict the dynamic response of electrodes for rechargeable batteries starting from the electronic structure. It will emphasize the link to in-situ experimental observations and illustrate how multi-scale studies of the dynamic response of electrode materials can elucidate the role of chemistry and crystal structure in causing hysteresis and degradation.
Na-Fe-S-O System As Cathode Materials for Na-Ion Batteries: An Ab Initio Study
Authors: Chung Sai-Cheong , Nishimura Shinichi , Yamada Atsuo
Published: February 2020

Sodium-ion rechargeable batteries have been attracting increasing interest as a cost effective alternative to lithium-ion batteries, particular for larger energy storage systems. However, sodium system has the intrinsic drawback of having lower voltage than lithium one. Exploration of cathode materials containing polyanions can led to high voltages and therefore is a meaningful remedy. Experiences gained in the studies of lithium battery show that sulphates (Li2Fe(SO4)2) deliver the highest voltage (3.83 V vs Li/Li+) among polyanions such as phosphates and silicates due to the high formal charge of S and inductive effects[1]. The Na-Fe-S-O system also has the advantage of composing of elements high in natural abundances and low in costs.

In exploring the Na-Fe-S-O system, our group found some new phases[2]. One of these can extract nearly all the Na atoms in the formula unit at an average voltage of 3.6 V vs Na/Na+. This is a significant improvement over the known Fe2(SO4)3 in the Nasicon phase[3], where only one Na atom can be inserted and at a lower voltage of 3.4 V vs Na/Na+. The rate capability and cycling performance are also very satisfactory. The new structure consists of peculiar edge sharing Fe2O10subunits forming tunnel spaces partially occupied by Na ions.

In order to understand the structural origin of the excellent performance of this material we carried out ab initio study employing density functional theory. Migration activation energy (Ea
) calculations found that Na ions are very mobile in the structure with Ea
as low as 0.14 eV (Figure). This accounts for the high rate performance and hints at the application as solid-state electrolytes. On the voltage aspect, emphasis will be put on the origin of the higher voltage of the present system in comparison to the Nasicon phase. Theory for the trend of voltage in cathode material employing different polyanions is well known, however, it is highly controversial for polymorphs of compounds with the same chemical compositions. Phase behavior at different state of charge will also be discussed.

　　　　　　　　　　　　

References

[1] J.B. Goodenough in H Reiss (Ed.) Progress in Solid State Chemistry, Vol 5. Pergamon Press, 1971, pp 145-387

[2] A. Yamada, P. Barpanda, S. Nishimura, G. Oyama, Patent JP-2013-187914 (2013).

[3] A.K. Padhi, V. Manivannan, J.B. Goodenough, J. Electrochem. Soc. , 145(5), 1518 (1998).
Polypyrrole Coated LiMn0.15Fe0.85 PO4 Olivine As High Capacity Cathode Electrode for the Lithium-Ion Battery
Authors: Gao Xuanwen , Wang Jiazhao , Liu Hua Kun , Chou Shulei , Chen Guohua , Deng Yuanfu , Shi Zhicong
Published: February 2020

Lithium iron phosphate has become the subject of great interest as storage cathodes for rechargeable lithium-ion batteries. Unfortunately, its intrinsic low electronic conductivity and low energy density still prevent it from practical commercialization [1]. In the past decade, Padhi et al [2] pioneered interest in the LiFe1-yMnyPO4 olivine system, showing the occupation of some percentage of octahedral 4c sites of LiFePO4 by Mn combines the advantages of the low toxicity of LiFePO4 and the relatively high operating voltage of LiMnPO4 (~4.1 V). This ability to increase the energy density of conventional LiFePO4 has been the driving force for extensive research on LiFe1-XMnxPO4 [3]. Nevertheless, besides the fundamentally low electronic conductivity of olivine, the Mn3+ doping may lead to another drawback, which is Mn3+ dissolution. It is generally accepted that Mn3+ causes serious mechanical stress and its disproportionation results in Mn2+dissolution from the surface by Jahn-Teller distortion [4]. Therefore, there have been many efforts to overcome these obstacles, for instance by decreasing the crystallite size and changing the morphology or providing a conductive matrix (e.g. carbon).

In this work, we present the application of a composite LiMn0.15Fe0.85PO4 coated with conductive polypyrrole (PPy) as cathode electrode for the Li-ion battery. The effects of the PPy coating on the physicochemical and electrochemical properties have been extensively studied. SEM and TEM images show that the PPy is uniformly coated on the surface of LiMn0.15Fe0.85PO4. The LiMn0.15Fe0.85PO4 electrode with 9 wt. % PPy coating exhibits a high discharge capacity and good cycle life at room temperature. This electrode delivers a discharge capacity of 135 mAh/g at 1/2 C, and after 100 cycles, the discharge capacity still reaches 126 mAh/g. In contrast, the discharge capacity of the pristine LiMn0.15Fe0.85PO4 is only around 128 mAh/g under the same conditions, and 114 mAh/g remains after 100 cycles, as shown in Fig. 1a. Electrochemical impedance spectroscopy verified the improved electrochemical conductivity of LiMn0.15Fe0.85PO4/PPy electrode. In addition, analysis of the counter electrode (Li film) confirmed that the PPy coating can protect the electrode from HF attack, and thus lead to reduction of Mn3+ dissolution in the LiMn0.15Fe0.85PO4-PPy electrode (Fig. 1b).

[1] A. Yamada, S. C. Chung, K. Hinokuma, Journal of the Electrochemical Society, 148 (2001) A224-A229.

[2] A. K. Padhi, K. S. Nanjundaswamy, J. B. Goodenough, Journal of the Electrochemical Society, 144 (1997) 1188-1194.

[3] S. Y. Chung, J. T. Bloking, Y. M. Chiang, Nat. Mater., 1 (2002) 123-128.

[4] R. Von Hagen, H. Lorrmann, K. C. Möller, S. Mathur, Advanced Energy Materials, 2 (2012) 553-559.
Cathode Properties of Rocksalt-type LiFeOF for Li-Ion Batteries
Authors: Kitajou Ayuko , Kidera Takafumi , Okada Shigeto
Published: February 2020

The iron-based conversion-type cathode materials attract attention due to the low cost and the high theoretical capacity. Among them, Fe2O3 has the highest theoretical capacity; FeF3 has the highest discharge voltage, and FeOF shows the highest energy density. However, these conversion-type cathodes can’t use in Li-ion type cell with carbonaceous anode, because they don’t include lithium-ion in the initial composition. Recently, K. Kang group reported LiF-FeF2 nano-composite can be used as cathode for Li-ion batteries [1]. Actually, LiF-FeF2 nanocomposite showed that the reversible specific capacity was ca. 190 mAh/g with the average voltage of 3.6 V. In this research, we tried to prepare LiF-FeO composite as the novel cathode materials for Li-ion batteries by dry mechanical ball-milling method. Moreover, the cathode properties of LiF-FeO nanocomposite were evaluated against lithium metal or Li4Ti5O12 (LTO).

LiF-FeO was prepared by mixing of LiF and FeO with a molar ratio of LiF : FeO = 1.2 : 1. The mixture was dry ball-milled in Ar for 24, 48 and 72 h, respectively. After mechanical ball milling, 5 wt % acetylene black (AB) was added to 70 wt % mixture in Ar for 24 h. Then, the 75 wt % obtained LiF-FeO/carbon composite power was also mixed with 20 wt % AB and 5 wt % PTFE teflon binder and punched in the form of disks (10 mm in diameter). The electrochemical performance was evaluated with a 2032 coin-type cell using a non-aqueous electrolyte (1M LiPF6 in EC:DMC=1:1 in volume) against Li metal anode or LTO anode.

Rocksalt-type LiFeOF was obtained from LiF and FeO by the dry ball-milling method under ambient pressure. The reversible capacity of LiFeOF was 292 mAh/g with an average voltage of 2.5 V and an energy density over 700 mWh/g, which is higher than the theoretical energy density of LiFePO4 (Fig. 1). In addition, we confirmed that a LiFeOF can actually work as cathode in Li-ion type cell with LTO anode. The initial charge and discharge capacities per cathode weight were 180 mAh/g and 149 mAh/g with an 83% discharge/charge efficiency. The discharge capacity was 130 mAh/g even after 30 cycles, and the cycling efficiency of LiFeOF was 87%. The reversibly expansion and contraction of structure of LiFeOF during cycling was measured with XRD.
Improving the Electrochemical Performance of Glucose-Derived Hard-Carbon Na-Ion Battery Anodes By Silicon Oxycarbide Embedment
Authors: Kaspar Jan , Storch Mathias , Graczyk-Zajac Magdalena , Riedel Ralf
Published: February 2020

Sodium-ion batteries (NIB) hold much promise for energy storage application due to the high abundance and low cost of sodium, combined with the low redox potential of Na/Na+ of -2.71 V vs. SHE, which is only 0.3 V above the one of Li/Li+. However, sodium-ion batteries are less explored and research for promising electrode materials is still a fundamental concern [1].

Within this work, we present a novel approach to increase the electrochemical performance of glucose-derived hard-carbon (HC-G) NIB-anodes by the preparation of silicon oxycarbide-based composites. In particular, the influence of an intrinsically carbon-rich (SiOC/HC-G) and carbon-poor (SiOC(N)/HC-G) ceramic as stabilizing matrix phase is discussed.

Materials were prepared by mixing of glucose with commercially available polysiloxane or polysilazane polymers, followed by thermolysis at 1000 °C. XRD identified the samples of amorphous nature, whereas Raman-Spectroscopy emphasized the disordered character of the generated hard-carbon phase. Compared to pure HC-G, both composites reveal higher insertion/extraction capacities (Figure 1). In addition, SiOC(N)/HC-G shows an excellent cycling stability, while the cycling stability of SiOC/HC-G is less. However, much higher capacities are obtained for the SiOC/HC-G sample. Moreover, SiOC/HC-G demonstrates the best coulombic efficiency of the first cycle of about 83 %, whereas the first cycle efficiency of pure HC-G only amounts 19 %; for SiOC(N)/HC-G 51 % are obtained.

In both cases, the glucose reacts with the polymer precursor upon thermal treatment, yielding a homogeneous composite after pyrolysis. The ceramic matrix acts as laminate towards the interspersed hard carbon and stabilizes the graphene layers against exfoliation during the subsequent insertion and extraction of sodium cations. In the case of SiOC/HC-G, the SiOC phase provides additional free carbon, accounting for the higher capacities. However the laminating effect is less, as compared to SiOC(N)/HC-G, which leads to the weaker cycling stability.

[1] S.-W. Kim, D.-H. Seo, X. Ma, G. Ceder, K. Kang, Adv. Enery. Mater., 2 (2012) 710-721.

Caption to Figure 1: Galvanostatic cycling performance of glucose-derived hard-carbon (HC-G) and SiOC-based/hard-carbon composites SiOC/HC-G and SiOC(N)/HC-G; current rate 37 mA/g.
High-Temperature Cycling Performance of Cathode with DLC Protective Film
Authors: Oka Yoshihiro , Obata Taiki , Takahara Hikari , Nakamura Tatsuya
Published: February 2020

One of the most important issues is related to the long cycling performance in the secondary batteries, considering their application to hybrid electric vehicle, electric vehicle and stationary storage system. Especially, the improvement of high-temperature cycling performance is the most challenging target. Under such an inhospitable condition, several reasons may be taken for the battery degradation. Among them, the side reaction at the electrode/electrolyte interface is taken place, irrespective to the kind of the electrode material. It can yield high-resistive interfacial layer, giving the kinetic limitation, and dissolution of transition metals, leading to the reductive precipitation on the anode surface. We have tried to suppress the side reaction with help of a diamond-like carbon (DLC) protective film and presented our experimental results.

The sub-nm DLC films were deposited by a hybrid process of plasma-based ion implantation and deposition (PBIID), which enables us to obtain uniform and thin coating at low processing temperature. This process is applicable to the cathode films as well as the electrode particles. In this study, the LiCo1/3Ni1/3Mn1/3O2 cathode film was treated as a typical electrode. An aspect of the DLC protective layer was observed by a cross-sectional TEM. It was found that the sub-nm DLC film was uniformly coated along the form of cathode surface without the damage to the cathode. The electrochemical cycling of the cathode film was evaluated with Li coin cell at the range from 2.5 to 4.5 V under the CC mode at 55°C. The DLC film coating had no influence on the initial charge-discharge properties but a significant positive effect on the cycling stability. For the cathode with DLC protective film, the discharge capacity hardly decreased even after 100th cycles. The cycling stability was also studied with the AC impedance spectra; it was found that the interfacial impedance growth during the cycling was suppressed by the presence of the DLC film. At the conference, the results about the surface analysis of the high-temperature cycled cathode will be presented and discussed.

This work was financially supported by Advanced and Seamless Technology Transfer Program through target-driven R&D, JST.
Improving the Electrochemistry of Anatase for Sodium Ion Batteries By Using Self-Organized TiO2 Nanotubes Prepared By Anodization Under Variable Voltage
Authors: González José Ramón , Alcántara Ricardo , Ortiz Gregorio F. , Nacimiento Francisco , Tirado José L.
Published: February 2020

The use of TiO2 as negative electrode in non-aqueous sodium ion batteries may show several drawbacks, such as the relatively low gravimetric capacity, low coulombic efficiency at low voltage and poor cyclability. To try to overcome these problems we have followed a new strategy: anatase-type TiO2 nanotubes (nt-TiO2) have been prepared by anodization of titanium under variable voltage. The titanium anodization process under variable voltage modifies de anodization curves (intensity vs. time) in comparison with the anodization under constant voltage at 100 V. As a result of the anodization process, self-organized TiO2 nanotubes with amorphous character are obtained. After annealing at 550°C in air atmosphere anatase-type nt-TiO2 are formed. The relative intensity of the anatase Bragg reflections are influenced by the anodization procedure.
The resulting areal capacity values in sodium cells are in the order of 1.0-1.5 mAh/cm2 (as refereed to the fingerprint area of nt-TiO2). When the anodization voltage is linearly increased from 20 to 100 V during one hour, the obtained anatase nt-TiO2 electrode material exhibits improved electrochemical performance. After six hundred discharge-charge cycles the gravimetric capacity vs. Na is about 200 mAh/g. Consequently, the electrochemical behavior in sodium cell of the anatase nt-TiO2 electrode material that we have prepared can be competitive in comparison to lithium.
On the other hand, the use of aqueous electrolyte batteries may be an alternative that is explored in this work. Using cyclic voltammetry, we have found that self-organized anatase nt-TiO2 vs. Pt electrode in aqueous NaCl solution exhibits reversible redox processes in the region between ca. -1.0 and -0.2 V. In contrast to the true insertion of lithium ions into the framework of anatase, the reaction with sodium rather takes place in the surface of nt-TiO2.
The Kinetics of Li+ Electrodeposition on Sn Substrate for Li Rechargeable Battery
Authors: Yang Yifu , Xu Qian , Shao Huixia
Published: February 2020

Sn can form alloy phase with Li with a theoretical specific capacity of 994mAh·g-1, which is more than twice of the graphite. Due to this property, Li-Sn alloy has been considered as one of the most appealing anode materials. In order to make this material to meet the requirements of real application, huge efforts have been devoted to the research of this material [1-3]. In this work, the kinetics of electrodeposition of Li+on Sn substrate is studied, and this can provide theoretical basis on improving the electrochemical properties of Li-Sn alloy anode materials.

Galvanostaticpulse method is used for the study of the kinetics of Li+ electrodeposition on Sn metal and Li-Sn alloy with different Li contents which is formed instantaneously with the deposition of Li. The polarization resistance of Li-Sn alloy electrodes with different Li contents is evaluated by EIS method. Meanwhile, the kinetics of Li+ electrodeposition on Li metal and Cu metal substrates are compared. Some conclusions can be drawn: firstly, Li+ electrodeposition on Sn substrate is a process with continuing change in exchange current density and polarization resistance. Secondly, Li content in Li-Sn alloy has great impact on the kinetics of Li+ electrodeposition, in which the Li-Sn alloy substrate containing highest Li content is the most beneficial one among them. Thirdly, the Li+ deposition performance on Li-Sn alloy substrate containing highest Li content is much better than on Li metal and Cu metal substrates.

References:

[1] M. Winter, J. O. Besenhard. Electrochimica. Acta, 45 (1999) 31-50.

[2] M. Inaba, T. Uno, A. Tasaka. J. Power Sources, 146 (2005) 473–477.

[3] S. C. Chao, Y. C. Yen, Y. F. Song, Y. M. Chen, H. C. Wu, N. L. Wu. Electrochemistry Communications, 12 (2010) 234–237.

Statement:

The novelty of this work is that, it is found that as the deposition of Li+ on Sn surface proceeds, the alloy of Li-Sn is formed with increase of Li content in the alloy. The exchange current density of Li+ deposition on the alloy is changed with the Li content. This feature could affect the overall kinetics Li+ deposition and the cycleability of Li metal anode.

Relating topic: electrode materials (Li battery anodes)
Ionic Liquid Based Synthesis of α-Fe2O3 nanocrystallite and Its Application in Lithium Ion Battery
Authors: Lu Yan , Wen Zhaoyin , Jin Jun , Rui Kun , Hu Yingying
Published: February 2020

Hematite (α-Fe2O3), which is the most stable iron oxide with n-type semiconducting properties under ambient conditions, is of great scientific and technological importance. Especially in the energy storage field, it has attracted considerable interest because of their low cost and excellent electrochemical properties in rechargeable lithium ion batteries (LIBs).[1,2] Stimulated by both the promising applications of iron oxides and the novel properties of nanoscale materials, considered efforts have been made in the synthesis of α-Fe2O3 nanoparticles, nanorods, nanowires and nanotubes. However, most of the synthesis approaches are complicated and beyond the large scale production. Herein, we report the preparation of α-Fe2O3 nanocrystalline using ionic liquid (BMIBF4) as morphology tuning agent through a facile, one step solvethermal method.

The role of ionic liquid (IL) played in the preparation process was investigated and a possible formation mechanism was proposed. Fig. 1 showed the morphologies of the products with and without ionic liquid in the reaction system. From which, we can see that uniform nanocrystallites were obtained with the addition of ionic liquid, demonstrating it a good morphology controllable agent for the products. Fig.2 showed that ionic liquid did not affect the phase of the products.

A series of experiments about the formation process ofα-Fe2O3 nanocrystallites have been carried out by changing the reaction temperature and time. The results showed that the product obtained at 180 °C for 36 hours exhibited the most homogenous morphology and the best dispersibility. The electrochemical performances of them were examined in rechargeable lithium batteries. Due to the poor conductivity of them, graphene nanosheets (GNSs) were used to composite with them to improve the electrochemical performance. As Fig.3 demonstrated, α-Fe2O3 nanocrystallites were successfully dispersed on the surface of GNS (Fig. 3a,b). It exhibited an initial discharge capacity as high as 1900 mAh g-1, which is much higher than that of primitiveα-Fe2O3 electrode of 1600 mAh g-1in Fig. 3c.

Figure 1. SEM image (a) and TEM image (b) of the product obtained at 180°C for 36 h with IL; SEM image (c) and TEM image (d) of the product obtained at 180°C for 36 h without IL.

Figure 2. XRD patterns of the product obtained at 180°C for 36 h with and without IL.

Figure 3. SEM images (a,b) of GNS supportedα-Fe2O3 nanocrystallites and the first charge-discharge curves of the electrodes at a current density of 50 mA g-1 in LIBs (c).

References

[1] J. Chen, L. Xu, W.Y. Li, X.L. Gou, Advanced Materials, 17 (2005) 582-586.

[2] J.Y. Zhong, C.B. Cao, Y.Y. Liu, W.S. Khan, Chemical Communications, 46 (2010) 3869-3871.
High Quality Graphene for Low Temperatures Lithium-Ion Batteries Application
Authors: Raccichini Rinaldo , Varzi Alberto , Chakravadhanula Venkata S , Kübel Christian , Balducci Andrea , Passerini Stefano
Published: February 2020

The properties of high quality few-layers graphene, produced though multisteps process involving microwave irradiation of expandable graphite, are presented. Such innovative approach fulfills all desirable requirements (so far missing in the conventional methods, e.g. Hummers method) of being reproducible, low-cost, environmental friendly, with high yield, and scalable.

When used as anode material the so-obtained graphene (hereinafter GRAL), differently from the commonly employed reduced graphene oxide, is able, similarly to graphite, to intercalate/de-intercalate Li ions in the few-layers structure. Its peculiar features such as (i) presence of few defects, (ii) small sheets size, and (iii) nanometric thickness, enable the negative electrode to work at considerably lower temperatures than conventional graphite.

During galvanostatic charge-discharge experiments (specific current of 50 mA g-1), performed in a temperature range comprised between +20°C and -30°C, GRAL exhibits remarkable capacity retention with comparison to commercial graphite. At temperatures above 0°C, GRAL performs quite similarly to graphite. However, at lower temperatures, graphite suffers from dramatic capacity decay resulting on only 9% of capacity retention at -30°C. On the contrary, GRAL is able to retain 65% and 34% of the room temperature capacity when operating at -20°C and -30°C, respectively.

The outstanding performances of this novel few-layers graphene are confirmed also by the very promising low temperature stability, with a coulombic efficiency close to 100%.
Metallization of Silicon Particles for Improved Li-Ion Battery Anodes
Authors: Spreafico Marco , Cojocaru Paula , Biso Maurizio , Apostolo Marco , Magagnin Luca
Published: February 2020

Silicon is a material that has gained particular interest for the application as anode active material in lithium ion batteries, thanks to its unique reversible lithium insertion capability, which can lead to very high values of specific capacity. However, the main drawback that prevented the spreading of this material in industrial application is its structural instability upon lithium insertion cycling, and different solution have been proposed to address this issue 1
,
2. The very high volume variation that occurs to silicon during cycling leads to difficulty to establish a continuative electrical contact between Si particles and the rest of the electrode. The approach developed in this work is to apply a nanostructured metallic coating to the Si particles, helping to overcome the continuous stresses during cycling and maintaining electrical contact.

In this work, two different metallization techniques have been tested. The presence and composition of the coating on the surface of the particles is confirmed by SEM/EDX and XRD analysis. Anodes containing at least 20%wt Si have been manufactured to perform the electrochemical characterization and to assess the cycling behavior. Coated particles show enhanced structural stability upon cycling, leading to improved cycling efficiency and cycle life. Specific capacity values around 1000 mAh/g are achieved with a 40% increase with respect to pristine Si.

References:

1. C. K. Chan et al., Nature nanotechnology, 3, 31–35 (2008).

2. B. A. Boukamp, Journal of The Electrochemical Society, 128, 725 (1981).
Synthesis and Morphological Influence on High Capacity LiMnBO3 Cathode Material for New Generation Lithium Ion Batteries
Authors: Veena Regupathi , Ganapathi Subramanian Nagarajan , Shanmukaraj Devaraj , Sudarkodi Raman
Published: February 2020

In search of new cathode material, Borate based electrode, LiMBO3 (M= Fe, Mn and Co) for lithium ion battery offer several attractive features, such as low molar mass, abundant, environmental friendliness and relatively high theoretical capacities (222 mAh/g) [1]. In this view,an effort towards improvement in electronic conductivity of LiMnBO3material via reduction in particle size and appropriate synthesis condition is reported in this paper.

A simplified Sol gel method was adopted for the synthesis of LiMnBO3cathode material. High Purity, analytical grade LiNO3, Mn(NO3)2. 6H2O and H3BO3 were used as precursors. The synthesized powders were annealed at 700oC for 3 hrs under different atmosphere.

Powder X –ray diffraction pattern of the LiMnBO3 revealed the presence of mixed phases of hexagonal and monoclinic in which hexagonal phase is dominant in both Ar and N2atm. [2]. The crystallite size (Debye –Scherrer) calculation indicated nanoparticle formation (~ 38 nm).

The SEM images of LiMnBO3 (Fig.1a) showed elongated spherical shaped particle in Ar atmosphere whereas peculiar tetragonal rod shaped particles was observed for N2atmosphere (fig.1b). The influence of morphological changes on the electrochemical performance is reported in this paper

Cycling profile of LiMnBO3 cells are given in fig.2. The cells were cycled between 1.5 to 4.8V at room temperature at a C rate of C/20. Fig.2, revealed that the capacity was maintained at 198mAh g-1for the first three cycles followed by a good capacity retention upto 35 cycles with a capacity deliverance of 190mAh/g (figure not shown).

From the results, we report a sol gel derived LiMnBO3 that delivers a first discharge capacity of 198mAh g-1 at C/20 rate, the best result reported so far for LiMnBO3to our knowledge.

References:

Shouli Li, et al, “In-situ controllable synthesis and performance investigation of carbon-coatedmonoclinic and hexagonal LiMnBO3 composites as cathode materials inlithium-ion batteries” - Journal of Power Sources, 236 (2013) 54e60

Yong –Suk Leeet al, “Structural and electrochemical behaviour of LiMnBO3 synthesised at various temperature” - Electronic Material Letters (accepted for publication)
A Sodium-Ion Battery Based on Olivine Sodium Iron Phosphate Cathode and Nanostructured Tin Carbon Anode
Authors: Hasa Ivana , Sun Yang-Kook , Hassoun Jusef
Published: February 2020

Lithium-ion battery is presently the most diffused energy storage system in the electronic portable devices market, this in view of its high energy density and intrinsic safety due the replacement of the reactive lithium-metal by the lithium-insertion, graphite anode. [1,2] The increased demand of lithium and its concentration in few countries contributed to a rapid rise of the price. As consequence, rechargeable electrochemical cells based on sodium, designed for the energy storage, are now attracting large interest due to its abundance and low cost. [3,4]

We report here the behavior of a sodium-ion battery based on a NaFePO4 cathode, obtained by electrochemical Li-Na conversion of LiFePO4 olivine, and a nanocomposite tin-carbon (Sn-C) alloying anode. [5,6] We show that, by adopting a refined, unique electrochemical process, the LiFePO4 can be successfully and efficiently converted in NaFePO4 and demonstrate that this material can be used as cathode in a sodium-ion battery characterized by the reversible electrochemical process NaFePO4 + SnC = Na(1-x)FePO4 + SnxC with good reversibility and rate capability.

[1] M. Armand and J.-M. Tarascon, Nature,7 February 2008, Vol 451;

[2] B. Scrosati and J. Garche, J. Power Sources, 2010, 195, 2419;

[3] M.D. Slater, D. Kim, E. Lee, C.S. Johnson, Adv. Funct. Mater., 2013, 23, 947–958;

[4] B.L. Ellis, L.F. Nazar, Current Opinion in Solid State and Materials Science, 2012, 16, 168–177;

[5]P. Moreau, D. Guyomard, J. Gaubicher, F. Boucher, Chem. Mater., 2010, 22, 4126;

[6]S.-M. Oh, S.-T. Myung, J. Hassoun, B. Scrosati, Y.-K. Sun, Electrochem. Comm., 2012, 22, 149–152;
Sulfur/Nitrogen Doped Carbon Nanotube Binder-Free Electrode for High Performance Li/S Batteries
Authors: Zhang Yongguang , Zhao Yan , Kurmanbayeva Indira , Bakenov Zhumabay
Published: February 2020

Introduction

Due to low cost, environmental friendliness and high theoretical capacity of sulfur, rechargeable Li/S batteries are very promising power sources for various applications. However, the insulating nature of sulfur and solubility of polysulfides as discharge products restrict its practical application [1]. Among the approaches to overcome these problems, carbon nanotubes are widely used to obtain a flexible conductive matrix for S cathode [2]. Nitrogen doping of carbon nanotubes (N-CNTs) significantly improves its electronic conductivity because the nitrogen atoms provide additional free electrons for the conduction band [3].

In this work, we report for the first time on a high performance S/N-CNT cathode for Li/S battery. Exclusion of heat-treatment in the composite preparation avoided the sulfur loss; the composite contained 61 wt% of sulfur. Thanks to the self-weaving behavior of N-CNT, binders and current collectors are rendered unnecessary, thereby simplifying the electrode manufacturing process and increasing the sulfur content in the total electrode weight. The N-CNT core provides a highly conductive and mechanically flexible framework, enhancing the electronic conductivity and consequently the rate capability of the material. This resulting composite cathode sustains 833 mAh g-1 reversible specific discharge capacity after 100 cycles at 0.1 C, and 676 mAh g-1at 1 C with a coulombic efficiensy about 100%.

Experimental

The S/N-CNT composite preparation is schematically shown in Fig. 1. Nitrogen doped carbon nanotubes were dispersed in deionized water by sonication at room temperature. The obtained N-CNT suspension was mixed ultrasonically with the aqueous suspension of nano-sulfur. The resulting system was vacuum-filtered and thoroughly washed with deionized water and ethanol. The binder-free S/N-CNT composite was obtained by further drying in a vacuum oven at 60 °C overnight to remove the solvent.

Acknowledgments

This research was supported by a Research Grant from the Ministry of Education and Science of Kazakhstan and by a Subproject supported under the Technology Commercialization Project by the World Bank and the Government of Kazakhstan.

References

1. X. Ji, K.T. Lee, L.F. Nazar, Nat. Mater., 2009, 8, 500.

2. Y.S. Su, A. Manthiram, Chem. Commun., 2012, 48, 8817.

3. X.G.Sun, X. Wang, R.T. Mayes, S. Dai, ChemSusChem
,2012, 5, 2079.
Cycling Performances of Lithium-Air Batteries Assembled with Ionic Liquid-Based Electrolytes
Authors: Han Sang-Min , Kim Jae-Hong , Kim Dong-Won
Published: February 2020

Li-air batteries have higher theoretical energy density than conventional rechargeable lithium batteries.[1,2] However, recent studies of Li-air batteries with conventional organic solvent-based electrolytes demonstrate that most of these solvents may not have long-term chemical stability in the presence of the superoxide radical.[3] Thus, improving the stability of electrolyte toward reduced oxygen species is the main key for developing the non-aqueous Li-air batteries with good capacity retention. In this work, we tried to investigate ionic liquid-based electrolytes for the Li-air batteries. They showed an oxidative stability higher than 5.3 V vs. Li/Li+, high ionic conductivity and good stability towards the superoxide radical. As a result, the Li-air batteries employing these electrolytes exhibited good cycling stability exceeding 100 cycles at a current density of 0.1 mA/cm². Good reversibility for oxygen reduction and evolution reaction was investigated by cycling voltammetry and ex-situ powder X-ray diffraction analysis.

References

[1] J. P. Zheng, R. Y. Liang, M. Hendricksonc, E. J. Plichta, J. Electrochem. Soc., 155(6), A432-A437(2008)

[2] Laoire, C. Ó., Mukerjee, S., Abraham, K. M., Plichta, E. J., Hendrickson, M. A. J. Phys. Chem. C, 114, 9178-9186(2010)

[3] F. Mizuno, S. Nakanishi, Y. Kotani, S. Yokoishi,. H.Iba, Electrochem, 78, 403- 405(2010)
Advanced Lithium-Sulfur Batteries with Carbon Nanotubes As Conductive Networks
Authors: Cheng Xin-Bing , Huang Jia-Qi , Peng Hong-Jie , Wei Fei , Zhang Qiang
Published: February 2020

Lithium-sulfur batteries, with the high theoretical capacity (1675 mAh g-1) and energy density (2600 Wh kg-1) as well as the easy access and non-toxic of raw materials, demonstrate a promising prospect among the high energy storage systems for electric vehicles (EVs) and portable electronic devices. However, there are also several issues to be handled before commercial application.

Firstly, different from traditional lithium-ion batteries, intermediate polysulfides generate and dissolve in the organic electrolyte during the discharge process of lithium-sulfur batteries. The dissolved polysulfides, shuttle between cathode and anode sides, lowering the utilization of sulfur and also react with the lithium anode without any electron transfer. However, the dissolution of polysulfide in a lithium-sulfur battery is highly dependent on the sulfur/electrolyte loading. Thus an appropriate dosage of electrolyte will build a concentration gradient, which will limit the dissolution of polysfulfides. In our work, A lithium-sulfur cell with a high initial discharge capacity of 1053 mAh g-1 at a high rate of 1 C and an ultralow decay rate of 0.049 %/per cycle during 1000 cycles was obtained by using CNT-sulfur cathode and suppressing polysulfide shuttle to a shuttle factor of 0.02 by matching the sulfur/electrolyte loading. Secondly, sulfur is with low electrical conductivity (5×10-30 S cm-1 at 25 oC) and extra conductive network is highly required. Generally, the addition of conductive materials will neutralize the advantage in high energy density of lithium-sulfur battery. Thus, the more sulfur content in the composite cathode, the larger energy density. Herein, we employed the carbon nanotubes (CNTs) to build the unblocked conductive skeleton and a room-temperature, one-step ball-milling treatment of aligned CNTs and sulfur was applied to obtain high sulfur content of 90 %. The 90 % sulfur loading cathode exhibited a superior density of 1.98 g cm-3 (2.07 g cm-3for sulfur), which will greatly increase the volumetric energy density of lithium-sulfur battery.

Reference:

[1] XB Cheng, et al. J. Power Sources, 2014, DOI: 10.1016/j.jpowsour.2013.12.031

[2] XB Cheng, et al. Nano Energy, 2014, accepted
Solvate Ionic Liquids for Lithium–Sulfur Batteries
Authors: Dokko Kaoru , Tachikawa Naoki , Ueno Kazuhide , Mandai Toshihiko , Watanabe Masayoshi
Published: February 2020

Introduction

Glyme, which has a chemical structure of CH3–O–(CH2–CH2–O)
n
–CH3, can coordinate Li+ ions forming a 1 : 1 complex cation of [Li(glyme)]+ when n is either 3 or 4. The coordination number of Li+ is typically 4–5, thus, n = 3 or 4 is suitable for the equimolar complexation. Consequently, the equimolar mixture of glyme and certain Li salt with weakly Lewis basic anion can be regarded as a room temperature ionic liquid consisting of [Li(glyme)]+ complex cations and the anions. [1]-[3] Herein, we present the solvate ionic liquids as excellent electrolyte candidates for Li-S batteries; these electrolytes greatly suppress the dissolution of lithium polysulfides. [4] ,[5]

Experiments

Electrolytes were prepared by mixing tetraglyme (G4) with lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]) in an Ar-filled glove box. Sulfur was mixed with Ketjen black (KB, specific surface area: 1270 m2 g–1), and polyvinyl alcohol (PVA) for cathode preparation. The mass ratio of S/KB/PVA in the composite cathode was 60:30:10.

Results and discussion

Figure 1 shows charge–discharge stability of Li–S cells with [Li(G4)
x

][TFSA] electrolyte measured at low current densities. The initial discharge capacity of each Li–S cell was in the range 800–1000 mAh g–1, which corresponds to 50–60% of the theoretical capacity of elemental S (1672 mAh g–1). The coulombic efficiency of the cell with [Li(G4)4] [TFSA] rapidly decreased with each charge–discharge cycle. The lower coulombic efficiency is attributed to the occurrence of the redox shuttle mechanism of lithium polysulfides (Li2S
m
) within the cell during the charge and discharge processes. In contrast, the cell with [Li(G4)1][TFSA] can be cycled more than 50 times while maintaining a coulombic efficiency above 98%. This high efficiency can be attributed to the low solubility of Li2S
m
in [Li(G4)1][TFSA], indicating that the solid state Li2S
m
remains in the composite cathode and undergoes a reversible redox reaction. [5]

Acknowledgement

This study was supported in part by ALCA of Japan Science and Technology Agency (JST).

References

[1] T. Tamura et al., Chem. Lett. 39 (2010) 753.

[2] K. Yoshida et al. J. Am. Chem. Soc. 133 (2011) 13121.

[3] K. Ueno et al., J. Phys. Chem. B 116 (2012) 11323.

[4] N. Tachikawa et al., Chem. Commun., 47 (2011) 8157.

[5] K. Dokko et al., J. Electrochem. Soc. 160 (2013) A1304.
Investigation of Lithium Solvated Ionic Liquid for High Performance Li-S Batteries
Authors: Seki Shiro , Serizawa Nobuyuki , Takei Katsuhito , Dokko Kaoru , Watanabe Masayoshi
Published: February 2020

1:1 equimolar complex electrolytes composed of low-molecular-weight ether (glyme) and Li salt have been reported to exhibit high thermal and electrochemical stability due to strong interactions between the oxygen in the ether and the Li cation (Li salt glyme solvate ionic liquids) [1]. Favorable performances were achieved using 3V-class [LiFePO4 | Li metal] and 4V-class [LiNi1/3Mn1/3Co1/3O2 | Li metal] cells [2]. Moreover, Li salt glyme solvate ionic liquids have a weak coordinating ability, which allows for innovative Li-sulfur batteries with a long cycle life (over 400 cycles) by suppressing the dissolution of polysulfide and redox shuttle [3]. More specifically, it is becoming clear that Li salt glyme solvate ionic liquids have important performance benefits besides their safety. In previous research, we used electrochemical quartz crystal microbalance (EQCM) measurements to show that an observed decrease in local viscosity near the electrode-electrolyte interface is attributable to the concentration distribution of Li salt and the transitional liberation of glyme molecules during the deposition of Li metal [4]. Therefore, to improve the electrochemical stability and polysulfide solubility of Li salt glyme solvate ionic liquids, it is necessary to form long-lived robust complexes between oxygen in the ether electrolyte and Li cations. So, we propose Li salt glyme solvate ionic liquids that are non-equimolar and that are prepared by adding Li salts to achieve a higher Li salt concentration than that in the original 1:1 equimolar complex of glyme and Li salt. Moreover, we investigated relationships between sulfur positive electrode (composite material of elemental sulfur and high surface area carbon) and Li-S battery performances. In the presentation, we will report the relationships between Li-S battery performances and electrolyte / electrode materials.

This study was supported by ALCA project, from JST, Japan.

[1] K. Yoshida, M. Nakamura, Y. Kazue, N. Tachikawa, S. Tsuzuki, S. Seki, K. Dokko, M. Watanabe, J. Am. Chem. Soc., 133, 13121 (2001).

[2] S. Seki, N. Serizawa, K. Takei, K. Dokko, M. Watanabe, J. Power Sources, 243, 323 (2013).

[3] K. Dokko, N. Tachikawa, K. Yamauchi, M. Tsuchiya, A. Yamazaki, E. Takashima, J-W. Park, K. Ueno, S. Seki, N. Serizawa, M. Watanabe, J. Electrochem. Soc., 160, A1304 (2013).

[4] N. Serizawa, S. Seki, K. Takei, H. Miyashiro, K. Yoshida, K. Ueno, N. Tachikawa, K. Dokko, Y. Katayama, M. Watanabe, T. Miura, J. Electrochem. Soc., 160, A1529 (2013).
Enhanced Cycle Performance Using PVDF-C Modified Separator for Lithium-Sulfur Batteries
Authors: Wei Hang , Xia Dingguo
Published: February 2020

Lithium-sulfur batteries with higher energy density are highly attractive, but the practical applications have been greatly affected by their poor cycle performance. Despite much effort has been devoted to design the structure of sulfur cathode to suppress polysulfide dissolution, relatively little emphasis has been placed on modifying the separator. Herein, we demonstrate a new approach of modifying the separator with polyvinylidene fluoride-carbon particle (PVDF-C) membrane, in which, the polysulﬁdes of lithium-sulfur cell can be localized in the cathode side and efﬁciently reused during cycling. The battery, based on the novel separator and the cathode by the simple mixing of sulfur powder and super P, can deliver a discharge capacity of 918.6 mAh g-1, 827.2 mAh g-1, and 669.1 mAh g-1 at 0.5C after 100, 200 and 500 cycles, respectively. Even under a current density of up to 5C, the cell could still retain 393 mAh g-1, showing an excellent high rate performance. The exceptional electrochemical performance could be attributed to both of the ripples induced by the fluorine atoms and micro-structure of the modified membrane. The economical and simple strategy to overcome the polysulfide dissolution issues provides a commercially feasible ways for the construction of lithium-sulfur batteries.