bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recovery of Gold Using Silicon Powder from Leaching Solutions
Authors: Arita Shotaro , Tsuda Takuya , Fukuda Kenji , Matsumoto Ayumu , Yae Shinji 
Published: February 2020

Low cost and efficient recovery of noble metals from urban mines (e.g., used electronic equipments) is important for securing scarce resources. We are developing a noble metal recovery technology utilizing electroless displacement deposition on silicon (Si)1. In this method, noble metals can be recovered by adding Si powder in metal salt solutions containing hydrofluoric acid (HF)2,3. For safety concerns, we are considering the use of highly basic solution instead of toxic HF solution. We have reported the effects of solution pH on the gold recovery from a basic solution4. In the practical applications, gold is recovered from leaching solutions. In this study, we examined the gold recovery from a basic solution simulating a thiosulfate-based leaching solution.
0.20 M (M: mol dm-3) Si powder (Kojundo Chemical Laboratory, 99.99%) with a particle diameter of 45 μm or less was added to a simple basic solution of 1 mM hydrogen tetrachloroaurate (III) solution pH-adjusted with sodium hydroxide, or a simulated leaching solution containing 1 mM sodium gold (I) sulfite, 1 M ammonium thiosulfate, 1 M ammonium hydroxide, and 0.5 mM copper (II) sulfate, which solution pH was at 9.3. The solution was stirred at 200 rpm using a magnetic stirrer and kept at 298 K of temperature. After filtering the solution, the concentrations of the metal in the filtrate were measured by an ICP-AES (Hitachi, SPS7800) and the recovery was determined from the change in concentration before and after the recovery process.
Figure 1 shows the recovery of gold from the simple basic solution (Fig. 1a) and the simulated leaching solution (Fig. 1b). The recovering rate form the simple basic solution was increased with solution pH. The long time treatment at the solution pH of 8 for 24h increased the recovery to 100%. Using bare Si powder, which was pretreated with a HF solution for dissolving an oxide layer on Si surface, shortened the treatment time to 45 min for getting 100% of recovery from the solution at the pH of 8. These results indicate that Si oxide layer inhibits gold recovery from the basic solution without fluoride species. The recovery of gold from the simulated leaching solution increased with treatment time and reached 98% or more at the treatment time of 120 min (Fig. 1b). The recovery of copper, which was added as the oxidation aid, was less than 10%. This suggests the possibility that gold is selectively recovered from the leaching solution including less noble metal than gold.

ACKNOWLEDGEMENT

The present work was partly supported by JSPS KAKENHI (JP26289276).

REFERENCES

S. Yae, N. Nasu, K. Matsumoto, T. Hagihara, N. Fukumuro, and H. Matsuda, Electrochim. Acta, 53, 35 (2007).

K. Fukuda, S. Yae, N. Fukumuro, S. Sakamoto, and H. Matsuda, ECS. Trans.,
53(19), 69 (2013).

K. Fukuda, N. Fukumuro, S. Sakamoto, and S. Yae, ECS. Trans.,
61(10), 1 (2014).

K. Fukuda, S. Arita, T. Tsuda, A. Matsumoto, and S. Yae, J. Surf. Finish. Soc. Jpn.,
69(6), in press (2018).

Figure 1
Improvement of Water Resistance of a Proton Conducting Phosphate Glass Electrolyte By Addition of ZnO or CaO
Authors: Shida Atsushi , Ogasawara Kiya , Shiroishi Hidenobu , Saito Morihiro , Tanaka Yumi 
Published: February 2020

Introduction

CsH2PO4 (CHP) has been studied as a solid electrolyte for an intermediate-temperature fuel cell. It shows relatively high proton conductivity (10–2 Scm-1) in the intermediate temperature (100–300℃) range. However, humidification is necessary to maintain the crystal structure of CHP, and water resistance is extremely low. We reported that proton conducting glasses (CHP-PO4) made from CHP and phosphoric acid shows high proton conductivity and excellent water resistance compared with CHP under dry N2. However, the water resistance of the phosphate glasses needs to be improved for application to solid electrolytes. Metal oxides such as CaO and ZnO are often added for improving the water resistance of glass. Thus, in this study, we attempted to further improve the water resistance by adding the above metal oxide to CHP-PO4. The effect on proton conductivity was also evaluated by AC impedance measurements.

Experimental

CHP was synthesized according to the literature1. A phosphate glass electrolyte was prepared by mixing CHP and 85 wt% H3PO4 at a molar ratio of 1: 1 and heating at 500 °C for 5 min, then raising the temperature to 900 °C for 15 min. The obtained melt was spread out on a copper plate heated at 180 °C, and quenched to obtain a phosphate glass electrolyte. Ca or Zn containing glasses (abbreviated as CHP-x(CaO or ZnO)-PO4) were prepared as follows: CHP, H3PO4 and ZnO or CaO were mixed in Cs : (Zn or Ca) molar ratios of 1: x and melted and quenched under the same conditions as mentioned above. Raman spectra were measured using NRS3100 (JASCO Co. Ltd.). The proton conductivity of the electrolytes was measured by an AC two-terminal method under dry nitrogen using an impedance analyzer (Yokogawa, HP-4192A). The water resistance test was conducted by the following method: The sample was immersed in 200 mL of ultrapure water with stirring at 100 rpm, and the amount of eluted hydrogen ions per unit surface area of the sample was determined with a pH meter (CUSTOM Co. Ltd, IWC-5).

Results and discussion

The results of the water resistance test of phosphate glass electrolytes are shown in Fig. 1. It was revealed that increase in the ZnO or CaO ratio in the samples results in the improvement of the water resistance.
The proton conductivities of the samples containing Zn or Ca were lowered to 10–3–10–4 S cm–1. Raman spectroscopic analysis of the phosphate glass revealed that the peak derived from ν(PO2)syn of the phosphate glass in CHP-x(CaO or ZnO)-PO4 shifted to the higher frequency by about 10 cm-1, which is attributable to the shorter phosphate chain. The present result suggested that the metal ions cross-linked phosphate chains and contribute the improvement of water resistance for the electrolytes.

Reference

1. Qing et al., Electrochim. Acta, 169, 219–226, (2015).

Figure 1
Improving the Cycling Stability of Sodium Metal Electrode By Making an Sodium-Carbon Composite Electrode
Authors: Kim Yun-Jung , Kim Hee-Tak 
Published: February 2020

The use of metallic anodes such as lithium and sodium has attracted large attention in the battery field because of their extremely high specific capacity and low operation potential. Indeed, the formation of metal dendrite upon repeated electrochemical plating/stripping cycling was early identified as obstacle of the development of safe metal anode secondary batteries. Also, due to dendrite formation, the low cycle efficiency and unstable cycle life happen, which hinder their practical application as anode materials. Therefore, to suppress the growth of metal dendrite is one of the most critical issues from a practical view point.
Recently, lithium metal has been extensively researched as anode candidate for secondary batteries due to its lowest redox potential and highest specific capacity among metallic anodes. Despite these promising properties, lithium sources are relatively limited and unevenly distributed across the globe, which lead to high costs of lithium metal batteries. Therefore, inevitably, lithium-based batteries will become unaffordable and large-scale production will falter. Therefore, sodium (Na) is one of the promising alternatives to lithium for energy storage technologies because of its relatively high theoretical specific capacity of 1166 mAh g-1 and natural abundance. Also, it has comparable redox potential, that is -2.70 V vs. SHE. However, like lithium metal anode, inhomogeneous electrochemical deposition of Na is a crucial problem that have to be solved for the usage of sodium metal as anode safely. Furthermore, Na metal has extremely high reactivity with liquid organic electrolyte, so high interfacial resistance could be induced due to continuous electrolyte decomposition during battery cycling, which also leads to earlier cell failure.
In this research, we present a stabilized sodium electrode by introducing electrically connected carbon network (ECN) to a bulk Na electrode with a simple folding & rolling method. As a results of introducing ECN, we observed that a cell overpotential was decreased as the amount of ECN inside bulk Na metal was increased. Also, we found that the cycling stability of Na/Na symmetric cell with ECN was almost 4.5 times increased compared to bare Na/Na cell, which is consistent with the results of EIS during cycling. By using SEM and CA analysis, we confirmed that an introduced ECN could act as not only an electrical network but also artificial uniform seed for Na nucleation.
Investigation of New Electrolyte Additives for Improvement of Nickel-Rich Cathode Materials at High-Voltage in Lithium Ion Batteries
Authors: Klein Sven , Winter Martin , Placke Tobias 
Published: February 2020

The continuous optimization of lithium ion batteries regarding the energy density, cycle life and safety has enabled their widespread application various fields, such as for electric vehicles. To satisfy the ever-increasing demands on both high gravimetric and volumetric energy density, high voltage and high capacity materials are being intensively studied. Promising candidates are the Ni-rich layered LiNixCoYMn1-x-yO2 materials. High Ni content LiNixCoyMn1-x-yO2 materials are attracting more attention in the last years due to their high specific capacity.
Compared to the other commercial cathode materials, e.g. LiFePO4, LiCoO2 and Li-rich materials, the high Ni content LiNixCoyMn1-x-yO2 materials such as LiNi0.5Co0.2Mn0.3O2 (NMC-532) possess high specific capacity ca. 200 mAh g-1 at a cut-off potential of 4.6 V vs. Li/Li+.(1)
However, the oxidative decomposition of conventional carbonate-based electrolytes at high voltages ( > 4.5 V vs. Li/Li+) and the deterioration of the active material particles result in rapid capacity fading. Different strategies are known to improve the cycle life of the high voltage cathode material NMC-532. One opportunity is to protect the cathode surface by inorganic coatings. Su et al. demonstrated the use of an Al203 coating which resulted in a significant improvement of the cycle life of NMC-532 by minimizing the structural transformation (2). A further option to improve the cycle life of NMC-532 is to use electrolyte additives (3). On the basis that the added additive decomposed prior to the electrolyte components, a cathode electrolyte interface (CEI) layer is formed on the cathode particles. This CEI layer on the cathode can prevent the electrochemical and chemical oxidation of the electrolyte.
In this work, we present the combination of both an inorganic coating and the use of electrolyte additives to significantly improve the cycle life of NMC-532/graphite LIB full cells at 4.6 V vs. Li/Li+.

References:

(1)Yan, G., et al. (2015). "Effects of 1-propylphosphonic acid cyclic anhydride as an electrolyte additive on the high voltage cycling performance of graphite/LiNi0.5Co0.2Mn0.3O2 battery." Electrochimica Acta 166: 190-196.
(2)Su, Y., et al. (2015). "Enhancing the High-Voltage Cycling Performance of LiNi0.5Mn0.3Co0.2O2 by Retarding Its Interfacial Reaction with an Electrolyte by Atomic-Layer-Deposited Al2O3." ACS Applied Materials & Interfaces 7(45): 25105-25112.
(3)Lee, S. H., et al. (2018). "[4,4′-bi(1,3,2-dioxathiolane)] 2,2′-dioxide: A novel cathode additive for high-voltage performance in lithium ion batteries." Journal of Power Sources 378: 112-118.
Thermal Stability Study of Commercial Lithium-Ion Batteries As a Function of Cathode Chemistry and State-of-Charge
Authors: Ferreira Summer , Barkholtz Heather , Ivanov Sergei , Lamb Joshua , Langendorf Jill , Chalamala Babu R. 
Published: February 2020

The safety of lithium-ion batteries is mainly quantified by thermal runaway characteristics such as onset temperature, peak heating rate (HR), and maximum pressure release. This talk evaluates the materials aspects of thermal runaway of commercial lithium-ion batteries by correlating the contributions from individual cell components to thermal runaway trends. An accelerating rate calorimeter was used to define the thermal runaway behavior of three commercial 18650 lithium-ion batteries (LiCoO2, LiFePO4, and LiNixCoyAl1-x-y­O2) at various states of charge (SOC). Cells were also disassembled and the thermal properties of their component materials was evaluated by thermogravimetric analysis, differential scanning calorimetry, and temperature-resolved X-ray diffraction. Broadly, lithium-ion battery thermal runaway process begins with solid-electrolyte interface and negative active material decomposition followed by the positive active material breakdown. The experimental results show that the onset temperature is generally independent of SOC and peak HR increases with SOC as a result of cathode destabilization. Overall, LiNixCoyAl1-x-yO2 decomposes readily, and charged LiCoO2 is also metastable, although it decomposes more gradually than LiNixCoyAl1-x-y. Contrary to the layered transition metal oxides, LiFePO4 is stable to > 500oC, even when charged. The results are aimed at informing future engineering and fire protection of commercial lithium-ion batteries.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2018-3360 A
Electrochemical and Mechanical Driving Forces for Lithium Electrodeposition
Authors: Jana Aniruddha , Woo Sang Inn , Vikrant Karra Suryanaryana , García R. Edwin 
Published: February 2020

It is well documented in the scientific literature that lithium electrodeposits grow into elongated "dendritic" structures from the top (tip-controlled) at high current densities and into mossy structures from the base (base-controlled) under low current densities [1,2]. In order to physically understand base-controlled growth, first an analytical model has been developed to incorporate the thermodynamic and kinetic driving forces of lithium to describe the multiphysical electrodeposition kinetics of lithium. Given the charging current density, the following regimes of lithium growth behavior are readily predicted from the analytical framework: (i) thermodynamic suppression regime, (ii) incubation regime, (iii) tip-controlled regime, (iv) base-controlled regime, and (v) mixed growth regime. These regimes explain the experimental observations and provide the kinetic boundaries between tip- and base-controlled growth [3]. Further, numerical calculations demonstrate that high von Mises stresses in localized regions of the lithium whisker extrude lithium and lead to base-controlled growth. In addition, the complex multiphysical dendrite-dendrite electro-chemo-mechanical interactions are rationalized through local electric fields, electrodeposition rates, mechanical stresses, and plastic velocities that are otherwise difficult to visualize in-situ in experiments. Overall, the combined analytical and the numerical frameworks provide multiphysical insight and serve as a design guideline for dendrite-free rechargeable batteries.
[1] O. Crowther, A. C. West. “Effect of electrolyte composition on lithium dendrite growth.” Journal of the Electrochemical Society, 155, A806-A811 (2008).
[2] P. Bai, J. Li, F.R. Brushett, M.Z. Bazant. “Transition of lithium growth mechanisms in liquid electrolytes.” Energy & Environmental Science, 9, 3221-3229 (2016).
[3] A. Jana, R.E. García. “Lithium dendrite growth mechanisms in liquid electrolytes.” Nano Energy, 41, 552-565 (2017).
Elucidating Mechanisms of Li Plating on Li Anodes of Lithium-Based Batteries
Authors: Qin Xueping , Shao Minhua , Balbuena Perla B 
Published: February 2020

Lithium metal is known as a promising anode material for lithium-based batteries, which possesses an extremely high theoretical capacity.1 The Li dendrite growth during the cycling of the battery has prevented it from being used as the anode directly.2 The origins of dendrite formation may be associated with the mechanisms of Li plating and with the mode of charge transfer during Li reduction or oxidation at the anode-electrolyte interface.3

Herein, density functional theory (DFT) calculations were conducted to analyze the electron transfer between Li (100) and Li cations located in the proximity of the surface in several simulation models. The study includes two common used solvents: ethylene carbonate (EC) and dimethoxyethane (DME), and a LiPF6 salt, which surround the Li cation over perfect, defect-containing and the Li2CO3 passivated Li (100) surfaces. Figure 1 shows the Li deposition on three-Li defect Li (100) surface. Three possible positions for the introduced Li cation were considered (as indicated A, B, and C, respectively in Figure 1a). The calculation results showed that the hollow site is the preferred deposition site (Figure 1b), which is in good agreement with the result of Li deposition on perfect Li (100) surfaces. Figure 1c shows the Bader charges of three defect Li and one introduced Li cation (red circled), located in the large electron-accumulation area. This added cation receives electrons and has a Bader charge of 0. In the other word, it was reduced and plated on the Li metal surface.
Our calculations demonstrate that the Li cation is easily reduced when bonding to DME rather than EC. Additionally, a compact Li2CO3 layer inhibits the charge transfer from Li metal to Li cations, thus manipulating the Li plating process. Furthermore, the diffusing and plating of Li cations through other SEI components, including LiF, Li2O and LiOH, will be studied to illustrate the protective role of coating layers.

References

(1) Kim, H.; Jeong, G.; Kim, Y.-U.; Kim, J.-H.; Park, C.-M.; Sohn, H.-J. Chemical Society Reviews
2013, 42, 9011.
(2) Xu, W.; Wang, J.; Ding, F.; Chen, X.; Nasybulin, E.; Zhang, Y.; Zhang, J.-G. Energy & Environmental Science
2014, 7, 513.
(3) Love, C. T.; Baturina, O. A.; Swider-Lyons, K. E. ECS Electrochemistry Letters
2015, 4, A24.

Figure 1. (a) side view and top view of three-Li defective slab (three possible deposition sites for Li cations are marked as A-top, B-bridge and C-center, respectively); (b) the most stable optimized deposition structure for the introduced Li cation; (c) charge density distribution for the most stable structure; the corresponding Bader charges (black numbers) of the three defect Li atoms and reduced Li are shown. In the charge density distribution diagrams, yellow represents the electron-accumulation area, while cyan is the electron-depletion area.

Figure 1
Variational Multiscale Modeling of Lithium Batteries
Authors: Liu John , Liu Lin 
Published: February 2020

Batteries are required to have higher energy and power density to meet the requirement of future electric vehicles and other power supply applications. To ensure the safety and durability of the high energy lithium batteries, the numerical study is the key to understanding and design of the next generation batteries. More importantly, the modeling and simulation study of lithium batteries help us understand the underlying causes of the electrochemical, electrical, thermal, and mechanical performance of a lithium battery under various operating conditions. However, the traditional modeling method of lithium batteries assumes the homogeneous structure and reaction to reduce the complexity of the model. The heterogeneity of the battery electrodes significantly impacts the performance of a battery. Due to the complex microstructure of the battery electrodes, it requires ultra-fine meshes to model the various length scales of the electrode structure, which requires very high computing power. This high computational cost is not practical for the numerical optimization design and long-term cycling simulations. Therefore, a variational multiscale method (VMM) is the key to model a lithium battery with considering the heterogeneity. The proposed VMM model reduces the computational cost of a realistic 3D battery model without compromise the accuracy of the heterogeneity. The VMM splits the battery model into macro-scale and micro-scale. By applying the micro-green function, which was firstly developed by Hughes [1] and then extended to battery modeling by us [2], as illustrated in Fig. 1, the micro-scale problem is analytically solved through the projection based on the macro-scale solution to obtain more accurate results. By doing so, we can significantly increase the computational efficiency and accuracy of conducting complex battery multi-scale simulations. With this method, we can simulate battery degradations in the realistic microstructure over hundreds of charge and discharge cycles with a reasonable computational cost. With the understanding of the battery behavior over long-term cycling, the battery electrodes can be redesigned to obtain longer lifetime and better performance through the numerical optimization for energy storage applications.
[1] T.J. Hughes, G. Sangalli, Variational multiscale analysis:
the fine-scale Green’s function, projection, optimization, localization, and stabilized methods. SIAM Journal on Numerical Analysis, 2007. 45(2): p. 539-557.
[2] L. Liu, M. Moradi, Towards a More Realistic Battery Model: Variational Multiscale Modeling of Li-Ion Batteries, ECS Transactions, 2017. 77(11): p. 273-291

Figure 1