bluuebunny/crossref_metadata_2025 huggingface dataset:
Carrier Selective Contacts Design for Efficient Photocatalytic Water Reduction
Authors: Bae Dowon , Pedersen Thomas , Seger Brian , Hansen Ole , Vesborg Peter C. K. , Chorkendorff Ib
Published: February 2020

2-photon tandem device structures that consist of a wide band gap and narrow band gap photoabsorber can maximize photoelectrolysis efficiency since their I-V characteristics match well with that needed for photoelectrolysis [1]. In the case of the narrow band gap (Eg
) material, recent theoretical work has shown that Si has a suitable Eg
for the bottom cell of tandem water splitting device [2]. Since current performance of Si PEC cells lag far behind the theoretical limit [3], the need for a different approach increases. Up to now, tremendous efforts have been made to improve the performance of Si-based photocathodes [4-6]. One approach the solar cells industry uses to increase performance is to use metal-oxide-semiconductor (MOS) carrier-selective contacts due to their efficient carrier transport and low recombination [5,6]. However, very little work has been done studying photocatalytic hydrogen evolution reaction (HER) with the MOS structure. Moreover, there has been no detailed report on energy band level analysis to understand how the carriers can be selectively injected.

In this work we demonstrate μc-Si/SiO2/p-Si structure (see Figure 1) to both front and back contacts which provide interface passivation and selective injection of minority and majority carrier to solid/liquid interface and back contact, respectively. A transparent TiO2 is placed above the highly doped μc-Si thin film as a conducting protection layer, and then Pt nanoparticles were drop-casted on the samples for photocatalytic HER in 1M HClO4. Using thin film degenerately doped Si as a metallic layer has been employed in recent state-of-art MOS based PV cells [7], but combination with TiO2 as a conducting protection layer for PEC hydrogen production has not been shown so far. Moreover, the details working principles based on the band energy analysis are outlined to understand how the carriers can be injected selectively and transferred to solid/liquid interface in PEC system.

1. B. Seger, I.E. Castelli, P.C.K. Vesborg, K.W. Jacobsen, O. Hansen, I. Chorkendorff, Energy Environ. Sci. 7 (2014) 2397–2413.

2. A.B. Laursen, S. Kegnæs, S. Dahl, I. Chorkendorff, Energy Environ. Sci. 5 (2012) 5577.

3. W. Shockley, H.J. Queisser, J. Appl. Phys. 32 (1961) 510–519.

4. D. Bae, T. Pedersen, B. Seger, M. Malizia, A. Kuznetsov, O. Hansen, I. Chorkendorff, P.C.K. Vesborg, Energy Environ. Sci. 8 (2015) 650–660.

5. D. V Esposito, I. Levin, T.P. Moffat, A.A. Talin, Nat. Mater. 12 (2013) 562–8.

6. A.G. Scheuermann, J.P. Lawrence, K.W. Kemp, T. Ito, A. Walsh, C.E.D. Chidsey, P.K. Hurley, P.C. McIntyre, Nat. Mater. (2015) 1–8.

7. F. Feldmann, M. Simon, M. Bivour, C. Reichel, M. Hermle, S.W. Glunz, Sol. Energy Mater. Sol. Cells. 131 (2014) 100–104.

Figure 1
Design of Metastable Alloys for Energy Conversion
Authors: Holder Aaron M. , Bikowski Andre , Siol Sebastian , Gorman Brian , Lany Stephan , Zakutayev Andriy
Published: February 2020

The design and discovery of new semiconductors with targeted multi-property functionalities for applications in solar energy conversion is a current challenge in developing new (photo-)electrode materials. Traditionally, theoretical predictions of ground state structures and their thermodynamic stability have facilitated the discovery of new materials and the optimization of known compounds. However, the field of materials design is experiencing a paradigm shift from near-equilibrium materials towards a much larger design space that includes materials far from equilibrium. In this work, we use theoretical and computational screening methods to identify and design metastable metal nitride and metal oxide alloys with desirable semiconducting properties for solar energy conversion applications. The materials design principles utilize both structure-property and composition-structure relationships to enable tunable multi-property functionalities. We leverage the possibility to overcome thermodynamic solubility limits by nonequilibrium thin-film growth to realize these novel semiconducting alloy electrode materials. Our theory guided synthesis employs a high-throughput combinatorial approach with reactive magnetron sputtering to rapidly screen composition and growth parameters to synthesize metastable spinel (Sn1-xTix)3N4 and polymorphic Mn1-xZnxO alloys. A proof of principle is provided by initial photo-electrocatalytic device measurements that corroborate the materials by design features of tunable band properties and transport mechanisms to improve solar hydrogen generation using the novel alloy electrodes. Our results demonstrate a broadly applicable approach for synthesis of metastable materials and establish the predictive design and discovery of far from equilibrium materials for energy conversion.

Figure 1
A Biomimetic Redox Flow Battery Based on a Flavin Mononucleotide
Authors: Orita Akihiro , Verde Michael , Sakai Masanori , Meng Shirley
Published: February 2020

Biological redox reactions inspire us to design sustainable and environmentally safe energy storage systems. Flavins have been demonstrated as solid-state electroactive materials for Li-metal batteries. [1,2] The concentration of flavin in those composite electrodes was no more than 50 wt%, however, due to the high content of conductive carbon necessary to complement the low electronic conductivity of flavin. In nature, flavins are often found dissolved in water or fat, such as in biological systems. As they are commonly more useful in this state, so may it be in batteries as well. Interestingly, flavins have yet to be reported as an active material for any redox flow batteries (RFBs). Here we explore the use of riboflavin-5’-phosphate sodium salt (FMN-Na) for RFBs. A diffusion coefficient and a kinetic rate constant of FMN in a strongly alkaline aqueous solution are determined and shown to be comparable to those of vanadium ions used for industrially utilized RFBs. Nicotinamide (known as vitamin B3) is used as a hydrotropic agent to enhance the water-solubility of FMN-Na, and therefore, its energy density in a RFB by as much as 15 times. A RFB using strongly basic FMN-based anolyte and ferrocyanide/ferricyanide-based catholyte shows highly stable cycling performance over the course of 200 cycles. The oxidized and reduced FMN can be stabilized by a variety of resonance structures, leading to the stable cycling performance. This work shows that biological redox centers are shown to be promising materials for environmentally friendly energy storage systems and warrant future exploration in this field.

References

[1] Hong, J. et al. Biologically inspired pteridine redox centres for rechargeable batteries. Nat. Commun 5, 9, (2014).

[2] Lee, M. et al. Redox Cofactor from Biological Energy Transduction as Molecularly Tunable Energy-Storage Compound. Angew. Chem. Int. Ed. 52, 8322-8328, (2013).
Polymer Electrolyte Membrane Based on Sulfonated Poly(phenylene oxide) for Vanadium Redox Flow Battery (VRFB)
Authors: Roh Sung-Hee , Jung Ho-Young
Published: February 2020

Polymer electrolyte membrane based on sulfonated poly(phenylene oxide) (sPPO) with high proton conductivity is prepared and its characteristics for VRFB are analyzed. Synthesis of sPPO polymer is confirmed by FT-IR and NMR analysis, and the basic properties of polymer electrolyte membrane are tested by DSC, water uptake, and dimensional change. The thermal and physical properties of sPPO polymer electrolyte membrane are in correspondence with DuPont’s Nafion 115 membrane, which is commonly used for VRFB. Therefore, it is found that sPPO with low cost and high performance can be an alternative polymer electrolyte membrane to commercial Nafion membrane.
Low Cost Membrane-Free Single Chamber Zinc Bromine Battery for Grid-Scale Electrochemical Energy Storage Applications
Authors: Biswas Shaurjo , Senju Aoi , Hodson Thomas , Steingart Daniel A
Published: February 2020

Climate change is a major global concern which can potentially be addressed by integrating renewable energy sources and low cost grid scale electrochemical energy storage (EES) systems. Most research efforts to improve energy storage have been directed to redox flow, lithium-ion and next generation sodium and multivalent batteries. The focus has been on incremental improvements in cost, and efficiency of electrode active materials and electrolytes. Most of these batteries still employ traditional cell designs with expensive passive components. Unfortunately, this approach results in the balance-of-plant costs far outweighing the cost of electrochemically active materials. Techno-economic analyses indicate that the cost of energy storage must be <$100/kWh and power cost <$600/kW. Commercially available EES systems today do not meet these targets. In addition, battery life and energy efficiencies must be over 10,000 cycles and 70%, respectively, to be a sustainable option. Based on these targets, a more holistic approach is needed when considering new energy storage system materials and designs.

Here, we discuss the design and working principle of a membrane free, non-flowing single-chamber zinc-bromine (SC-Zn-Br2) battery that utilizes the physical properties of liquid bromine, a porous carbon foam electrode, and also allows zinc dendrites to form freely. With this design, we eliminate the need to use failure prone and expensive passive components such as membrane separators, bromine complexing agents, flow-rated hardware, and control software as employed in traditional Zn-Br2 redox flow batteries (RFB). The ultimate figure of merit for feasibility in grid-scale EES system is $/kWh over its lifetime (cycles) at a given energy efficiency, or levelized cost of energy stored (LCOES). We demonstrate an SC-Zn-Br2 system with a maximum specific capacity of 89 mAh/g and energy density >150 Wh/kg (normalized to the mass of ZnBr2 salt in the electrolyte) and cell cost of $94/kWh including passive components. We achieve coulombic and energy efficiencies of up to 95% and 75%, respectively, for over 1000 cycles. The LCOES of SC-Zn-Br2 is shown to be an order of magnitude better than Zn-Br2 and vanadium RFB, as well as grid-scale lead-acid batteries and Li-ion batteries.
NaCrO2 Cathode for High-Rate Sodium-Ionbatteries
Authors: Myung Seung-Taek , Park Jae sang , Jung Hun-Gi , Chung Kyung Yoon , Aurbach Doron , Yu Chan-yeop , Sun Yang-Kook
Published: February 2020

Layered lithium intercalation compounds LiMeO2 (where Me is transition element) materials have been widely studied and applied as cathode materials for practical lithium ion batteries. Cost of lithium resource, however, has doubled since commercialization in 1991, and tight supply is expected due to the ever increasing demands of electric vehicles and energy storage systems. Indeed, the lithium resource is unevenly distributed in Southern America. Meanwhile, sodium resources are abundant and unlimited everywhere. Recently, layered NaMeO2 materials are being intensively studied because of reversible Na+ insertion/extraction, in particular, NaCrO2 (R-3m) in Na cell. Here, we report physical and electrochemical properties of NaCrO2. The NaCrO2 powder was synthesized by solid-state method. Stoichiometric mixture of Na2CO3 and Cr2O3 powders were pelletized, and the pellet was heated at 900 oC in Ar. All chemicals and products were handled in an Ar-filled gloved box to avoid air exposure. Phase identification of the products was made using X-ray diffraction (XRD) with Cu Kα radiation and the collected XRD data were analyzed by the Rietveld refinement. Electrochemical test were carried out in coin type sodium cells. Galvanostatic electrochemical charge and discharge tests in 1M NaClO4 in PC solution were carried out at room temperature. XRD pattern of the produced NaCrO2 demonstrated a phase-pure product and it was crystallized to O3 type layer structure with space group of R-3m. The delivered capacity was approximately 110 mAh (gNaCrO2) -1 in voltage range of 2 – 3.6 V and 97 % of the capacity was retained during 50 cycles. Also, the Na/NaCrO2 cell exhibited surprising high rate properties, namely, 84 % of capacity retention at 100 C-rates. Details will be discussed in the conference site.

Figure 1
Crystal Structure of Na2Fe2(MoO4)3 As a Positive Material for Sodium-Ion Batteries: Determination of the Inserted Sodium-Ion Positions from Powder X-Ray Diffraction Data
Authors: Heo Jongwook W , Hong Seung-Tae
Published: February 2020

Rechargeable sodium-ion batteries (NIBs) have been considered as promising candidates for alternatives to lithium-ion batteries due to the low cost and abundance of sodium. Recently, Fe2(MoO4)3 has received an attention as a positive electrode material for NIBs.1-4 There are two polymorphic phases for Fe2(MoO4)3: the low-temperature monoclinic phase and the high-temperature orthorhombic one,1 where the monoclinic one was recently reported as the positive material for NIBs. The previous reports mainly focused on synthesis and methods to improve the cycle and rate performances.2-4 Regarding the structure of electrochemically sodium-intercalated phase Na2Fe2(MoO4)3, only the cell parameters and space group were reported:1,5 the positions of the inserted sodium ions have never been determined at the best of our knowledge.

In this work, the monoclinic Fe2(MoO4)3 has been synthesized by sol-gel method at 600°C from Fe(NO3)3.9H2O, (NH4)6Mo7O24.4H2O and citric acid. The electrodes consisted of Fe2(MoO4)3 (80 wt %), Super-P carbon (10 wt %), and polyvinylidene fluoride binder (10 wt %). The sodium-intercalated phases NaxFe2(MoO4)3 were obtained by the galvanostatic discharge in the electrolyte of 1M NaClO4 in acetonitrile with the activated carbon as the counter electrode. Reversible structural changes of NaxFe2(MoO4)3 (0 ≤ x ≤ 2) were observed in ex-situ powder X-ray diffraction patterns during the discharge and charge cycle. The crystal structure of the fully sodiated phase of the monoclinic Na2Fe2(MoO4)3 has been determined for the first time using the techniques of structure determination from powder X-ray diffraction data, locating the inserted sodium-ion positions in the unit cell. The results presented here would provide an important basis for understanding the mechanism of sodium intercalation into Fe2(MoO4)3.

References

1. J.L. Yue, Y.N. Zhou, S.Q. Shi, Z. Shadike, X.Q. Huang, J. Luo, Z.Z. Yang, H. Li, L. Gu, X.Q. Yang and Z.W. Fu, Scientific Reports 5, 8810 (2015).

2. Q. Sun, Q.Q. Ren and Z.W. Fu, Electrochem. Commun. 23, 145 (2012).

3. V. Nguyen, Y. Liu, Y. Li, S.A. Hakim, X. Yang and W. Chen, ECS J. Solid State Sci. Technol. 4, M25-M29 (2015).

4. V. Nguyen, Y. Liu, X. Yang and W. Chen, ECS Electrochem. Lett. 4, A29-A32 (2015).

5. P.G. Bruce and G. Miln, J. Solid State Chem. 89,162 (1990).

Figure 1
Enhancement of Lithium-Sulfur Batteries By Introducing Metal-Organic-Framework (MOF) Coated Separators
Authors: Sun Seho , Choi Junghyun , Kim Joo Hyun , Kim Youngsik , Paik Ungyu
Published: February 2020

Sulfur has received high attention as an advanced cathode material due to the advantages of its high theoretical energy density of 2600Wh/kg, environmental friendliness, and cost-benefit. Despite of its many strong points in lithium sulfur batteries, it is not sufficient to practically use the sulfur cathode in commercial lithium-ion batteries due to the active material loss and the polysulfides shuttling effect. To address the above-mentioned challenges, two main approaches have been intensively investigated: a) Control of dissolved polysulfide intermediates in electrolyte by designing scaffolds of sulfur or electrolytes. b) Confinement of polysulfides within the sulfur cathode side by introducing an additional interlayer in-between sulfur cathode and separator. However, there are few approaches on a separator only to prevent the migration of sulfur species to the anode for electrochemically stable lithium sulfur batteries. Here, we suggest inserting metal-organic-framework (MOF) coated separator by using simple surface modifying strategy with polydopamine (PDA). MOF has interesting properties such as high porosity, chemical absorption and catalytic property. MOF coated separator effectively retards the diffusion of polysulfides to counter electrode due to its physicochemical sorption property. The sulfur battery with MOF coated separator shows an improved cycle performance and high specific capacity, compared to pristine separator.

Figure 1
Electrospun Hollow Carbon/Sulfur Nanofiber for Lithium-Sulfur Battery
Authors: Yun Jong Hyuk , Kim Joo-Hyung , Kim Do Kyung
Published: February 2020

Lithium ion battery (LIB) is the most widely used rechargeable battery for portable devices because of their high energy density (387 Wh kg-1) and long cycle life. Nevertheless, the energy density of LIBs is insufficient to meet the demands for grid energy storage system or electrical vehicles. Lithium sulfur battery (LSB) is one of the most promising systems for alternative rechargeable battery. Elemental sulfur has a high theoretical specific capacity of 1675 mAh g-1 and lithium-sulfur battery has a theoretical energy density of 2500 Wh kg-1. Moreover, LSB has many advantages such as low cost, non-toxicity and abundance. In spite of the considerable promises, there are multiple challenges must be solved; intrinsic poor electrical conductivity of sulfur (5 × 10-30 S cm-1 at 25 oC), dissolution of polysulfides (Li2Sx, 4≤x≤8) in electrolyte and large volumetric expansion (~80%) of sulfur during cycles. To overcome the problems, carbon based materials such as porous carbons, hollow carbon spheres, CNTs, graphene have been investigated as a conductive and structural matrix for carbon/sulfur composites. Although the above-mentioned composites showed outstanding improvement of capacity and cyclability, the specific capacity could not reached near the theoretical value yet. Additionally, finding a suitable structures for high areal capacity which is able to accommodate a high sulfur content is the issue for commercialization of LSBs. In this study, we developed a carbon/sulfur electrode which is focused on electrode design. Electrospun hollow carbon/sulfur nanofiber was designed for cathode material and carbon matrix could be a current collector itself. Because of the thin nanosized structure, electrons could reach the inner part of sulfur so that the sulfur was easily utilized for electrochemical reaction and showed high specific capacity due to high utilization of sulfur. Also, the resulting intertwined nanofibers showed porous structure. Highly porous structure accommodated electrolyte effectively and offered abundant electrochemical reaction sites with a large surface area. Moreover, this electrode was produced easily with simple electrospinning method and showed high areal capacity. We investigated the performance of the carbon/sulfur nanofiber cathode by electrochemical test. The morphology was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
(Invited) Sion Power
Authors: Mikhaylik Yuriy , Kovalev Igor , Scordilis-Kelley Charlie , Laramie Michael , Kelley Tracy
Published: February 2020

Sion Power Corporation has created
Licerion®

, a comprehensive battery system that significantly enhances energy and cycle life of rechargeable batteries with metallic lithium anode. The core element of Sion Power’s
Licerion®

technology is a physically protected metallic lithium anode. Physical protection is based on ceramic-polymer composite membranes and is combined with specialized cell design and electrolyte systems providing smooth, dendrite-free lithium deposition and chemical protection of exposed metallic lithium surface. This approach addresses safety and cycle life problems that have historically plagued lithium metal electrodes. Protected lithium anodes are currently combined with intercalated metal oxide cathodes typically used for Li-ion batteries (
Licerion®

- Ion) and with advanced sulfur cathodes (
Licerion®

- Sulfur). Sion Power Corporation in collaboration with BASF is working aggressively on realizing the impressive potential of the
Licerion®

technology targeting 500 Wh/kg, 1000 Wh/L and 1000 cycles. This presentation will discuss:

Failure mechanisms of rechargeable batteries with metallic lithium anode.

Approaches pursued by Sion Power in collaboration with BASF towards next generation of
Licerion®

- Sulfur and
Licerion®

- Ion batteries targeting to meet and exceed requirements for EV application and for extended unmanned aerial vehicle (UAV) flights.

Current status of 350 - 450 Wh/kg
Licerion®

- Ion and
Licerion®

- Sulfur batteries their cycle life and high power and extreme low temperature variations.
Sulfur-Embedded Polymers for High Performance Li-S Batteries
Authors: Choi Jang Wook
Published: February 2020

Lithium–sulfur (Li–S) batteries have received considerable attention because high gravimetric capacity of sulfur can enhance the energy density of the cell far beyond those of current lithium-ion batteries (LIBs). However, the shuttling process originating from polysulfides dissolution and the low electronic conductivity of sulfur impose a significant technological bottleneck for practical application of Li-S cells. As attempts to overcome these intrinsic drawbacks of sulfur cathodes, in this presentation, I will introduce sulfur-embedded polymer designs, such as sulfur-containing covalent triazine frameworks1 and sulfur-embedded benzoxazine polymers2. Both polymers exhibit extraordinary cyclability utilizing well-dispersed sulfur domains designed from the monomer-level molecular structures. Especially, both polymer classes showed superior initial Coulombic efficiencies and volumetric capacities, both of which have been difficult to achieve with conventional sulfur cathodes.

1Elemental Sulfur Mediated Facile Synthesis of a Covalent Triazine Framework for High Performance Lithium-Sulfur Batteries,
Angew. Chem. Int. Ed.
, 2016, 55, 3106-3111

2Under review
Voltage Delay Action of Na Metal in Na/MnO2 Non-Aqueous Cells
Authors: Kishore Brij , Munichandraiah N
Published: February 2020

The Li based battery systems, namely Li-ion, Li-O2 and Li-S batteries have occupied top importance in research and development activities at present. However, Na based battery systems are gaining interest for the next generation non-aqueous batteries. This is primarily because of limited and uneven global resources of Li for large scale production of Li-ion batteries for future applications such as electric vehicles. Plentiful resources of Na and its electrochemical properties close to those of Li have instigated research activities on Na-ion batteries similar to Li-ion batteries. Electrode materials suitable for Na-ion batteries are under investigations and they are characterized for their electrochemical properties by assembling experimental cells in combination with Na metal as the counter electrode as well as reference electrode [1]. Primary batteries employing Na metal as the anode similar to Li based primary batteries are also expected to gain momentum [2]. The cells employing Na metal in non-aqueous electrolytes experience voltage delay on initiation of cell discharge. The voltage delay action arises due to the presence of surface film on Na.

            In the present studies, Na/MnO2 cells are assembled in a non-aqueous electrolyte and the voltage delay properties are investigated. Coin cells of type CR2032 with Na foil and MnO2 coated stainless steel mesh as the negative and positive electrodes, respectively, are assembled. The electrolyte was 1 M NaPF6 in a mixture of ethylene carbonate and propylene carbonate (1:1 by volume). Na foil was sliced from a lump of Na in Ar atmosphere glove box before the cell assembly. Amorphous MnO2 was used as the positive electrode material. As shown in Fig. 1 typically, there is a large voltage drop on commencing the cell discharge by passing current in galvanostatic mode. Following the instantaneous voltage fall from open circuit voltage (V1) to dip voltage (V2), then, cell voltage rises gradually and reaches the operating plateau voltage (V3) of the cell. The surface film on Na exhibits its first appearance and it undergoes dielectric breakdown in the high field, which are reflected in the initial voltage fall. Subsequent to the breakdown of surface film, bare Na surface contacts the non-aqueous electrolyte and undergoes oxidation to Na+ ions under the galvanostatic conditions with a simultaneous building of electric double layer. From the data obtained under several experimental conditions such as current density and cell ageing, the properties of surface film on Na metal are evaluated. Results of these studies will be discussed.

References:

1. L. P. Wang, L. Yu, X. Wang, M. Srinivasan and Z. J. Xu, J. Mater. Chem. A,
3, 9353 (2015).

2. Brij Kishore, G. Venkatesh, and N. Munichandraiah, J. Electrochem. Soc.,
162, A839 (2015).

Figure 1
Surface Modifications of LiMn2O4 electrode for Aqueous Lithium Ion Batteries
Authors: Mun Junyoung , Tron Artur V. , Kim Jaemin , Go Nakgyu , Jo Yong Nam , Choi Wonchang
Published: February 2020

1. Introduction

The rechargeable lithium-ion batteries (LIBs) have been considered as the power sources for the various applications from portable devices to high power applications such as electric vehicles and power storage for renewable energy [1]. However, their safety concerns and high cost are issues restricting their field for large scale energy storage system because the conventional LIBs contain the large energy and dangerous carbonate electrolyte. In this regards of safety and cost, the aqueous electrolyte can be the best candidate [2]. However, its practical application was limited due to its decreasing cycle life from poor electrochemical stability window. Here, we have shown that surface modifications of LiMn2O4 showed highly improved rate and cycle life in aqueous electrolyte.

2. Results and discussion

The effect of the surface coating on the electrochemical properties of LiMn2O4 cathode in aqueous electrolyte solution was investigated by systematic electrochemical and instrumental analyses. The electrochemical performance of pristine LiMn2O4 and coated LiMn2O4 is presented. Despite the high ionic conductivity of the aqueous electrolyte (1 M Li2SO4 in water), the pristine LiMn2O4 did not show the high rate capabilities. In detail, the pristine and coated LiMn2O4 by 1,2, and 3wt.% AlF3 in aqueous electrolyte deliver the initial discharge capacity of 109.7, 106.6, 103.4 and 99.0 mAh g−1 at 1 C, respectively. The AlF3 coating has a dual role of surface stabilizer and resistance for lithium transportation. Based on these results, it is confirmed that the resistance from the surface failure mode of LiMn2O4 could be a main hurdle for cycle decaying especially in the aqueous electrolyte. After the surface modification of the electrochemically stable inorganic species, the rate capability and the cycle life are further improved. This coating enhance the surface stability to the aqueous solution and presents very promising cycle and rate capabilities for the development of ARLBs. Furthermore, they are investigated in detail by using XPS, SEM and TEM analyses.

Acknowledgments

This research was supported by the Post-Doctor Research Program (2014-2015) through the Incheon National University (INU) and the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (NRF-2014R1A1A1038248).

Reference

[1] M.R. Palacin, Recent advances in rechargeable battery materials: a chemist’s perspective, Chem. Soc. Rev. 38 (2009) 2565-2575.

[2] W. Li, J.R. Dahn, D.S. Wainwright, Rechargeable Lithium Batteries with Aqueous Electrolytes, Science 264 (1994) 1115-1118.
Honeycomb-Layer Structured Na3M(II)2M(V)O6 Cathode for Sodium-Ion Batteries
Authors: Nam Kyung-Wan
Published: February 2020

The necessity to find sodium ion battery cathodes with high capacity and improved cycle life has stimulated the research on sodium containing layered transition metal oxides. With this perspective, we have examined the electrochemical properties of highly ordered, honeycomb layered oxide Na3M(II)2M(V)O6, with monoclinic super structure as a cathode in sodium ion battery. One of this class materials, Na3Ni2BiO6, is able to reversibly deliver specific discharge capacities of up to 109 mAh/g with very flat voltage plateaus ~3.5V vs. Na/Na+. Complex structural changes occuring during charging/discharging is investigated by using in situ X-ray diffraction (XRD). Long range- as well as local- structures at different charged/discharged states have been also probed ex situ using combined synchrotron based x-ray techniques such as high resolution XRD (HRPD) and extended X-ray absorption fine structure (EXAFS). The Ni3+/Ni2+ active redox couple during charge/discharge is also confirmed by X-ray absorption near edge structure (XANES) spectroscopy.
Tailored Transition Metal Oxide Spheres Using Versatile Polymer-Template for Sodium-Ion Battery Cathodes
Authors: Song EunHee
Published: February 2020

Transition metal oxides have been studied as positive- and negative-electrode materials for sodium-ion batteries (SIBs). In this study, we report the strategic synthesis methods of tailored cathode materials for high performance SIBs using external-stimuli responsive polymer particles and water-in-oil system. The primary particles consisting of the polymer and metal precursors are fabricated by introduction of various metal ions and polar molecules into the three-dimensional cross-linked polymer spheres in aqueous solution. The assembled secondary metal oxide spheres with tailored structures were prepared by water-in-oil system and heat treatment in high purity oxygen. When tested in an electrochemical Na-half cell, the tailored transition metal oxide spheres exhibit good Na storage capabilities.
Nanorod Assembly in a Spherical Secondary Particle for High-Energy Sodium Ion Batteries
Authors: Hwang Jang-Yeon , Sun Y.-K.
Published: February 2020

Nowadays, to adjust the fluctuations in electricity production and efficient use of midnight off-peaks for stable energy supply, the mid-large scale battery system has been growing up. In particularly, sodium ion batteries have many interests as an alternative candidate for cost-advantage versus lithium ion batteries because of large amounts of reservation of sodium resources in earth. However, intrinsic structural disadvantage of interstitial tetrahedral sites dissimilar to the O3 structure led to the low discharge capacity and cycle retentions and it have not yet satisfactorily addressed. Recently, to breakthrough present drawbacks, we suggested the new concept of radially aligned hierarchical columnar structure with varied chemical composition

To further study of novel nano-structured with varied chemical composition materials, we carry out the synthesis and characterization of O3-type layered structure cathode material of constant concentration and full concentration gradient material. Through the comparison of electrochemical properties and related structural properties, herein, we investigated and defined the novel concept FCG materials.

Especially, we focus on the effect of particle morphology and micro structured properties by using various analysis technique. Micro-compression testing and single particle electrochemical measurement results demonstrate the robustness of the spherical particles and the associated Na+ ion mobility in the particles. These significant improvements provided by the tailored structure are appealing for utilizing sodium ion. We believe that the unexplored site of radially assembled nano-rod structure primary particles having varied chemical composition is highly contribute to high power and high energy Na-ion battery systems.
Charge-Discharge Properties of a Phosphoric Acid Material System for Application in Sodium Ion Batteries
Authors: Nagao Keisuke , Takahashi Hiroo
Published: February 2020

The demand for high capacity and safe rechargeable batteries has significantly increased in recent years due to sustainable development issues. In order to supply such demand, the cost related to batteries remains a critical factor. Recently, sodium has attracted much attention as charge carrier because this element is abundant and low cost. In fact, it was found that some layered materials can be used efficiently as positive electrode materials in sodium ion batteries. Sodium is inserted between layers, which are composed of metals and oxygen. Therefore, such materials consist in 2D sodium channels. Although layered materials exhibit a high capacity, their low stability remains problematic. Furthermore, the weakness of oxygen bonds raises security issues. Herein, a novel phosphoric acid material system used as positive electrode material is proposed. In these systems, the strength of the bond between oxygen and phosphorus increase significantly the safety of the batteries. The stability of the material was thermodynamically tested and safe operation was achieved at 400 ºC. The charge-discharge properties and structural analysis of the material are reported herein.
Charge Transport Mechanism in Solid-State Redox-End Members in Lithium-Sulfur(Li-S) Batteries
Authors: Park Haesun , Kumar Nitin , Siegel Donald J
Published: February 2020

The insulating nature of solid state redox end members (Li2S and S) in Lithium-Sulfur (Li-S) batteries may result in performance limitations in cells that minimize or eliminate the solubility of polysulfides. For example, the formation of Li2S films on the cathode surface during discharge could give rise to the sudden death of voltage of the cell. To prevent these limitations it is helpful to understand charge transport mechanisms in Li2S and S, which are poorly understood. Here, we characterize these mechanisms using first-principles calculations. In particular, we examine the concentrations and mobilities of intrinsic defects such as vacancies, interstitials, and localized electrons/holes (polarons) in both compounds. We describe how these data can be used to inform a continuum model of transport that allows for estimation of the critical thickness of Li2S and S films, and relate this to a critical cell capacity.
Study on Lithium-Sulfur Batteries
Authors: Wang Yong-Gang , Wang Lina , Yuan Shouyi , Xia Yong-Yao
Published: February 2020

Lithium-Sulfur (Li-S) batteries have recently raised worldwide attention owning to the high specific theoretical energy density of sulfur (2600Wh kg-1), the low cost and the wide availability of sulfur. However, the practical application of lithium-sulfur batteries has been hindered by several challenges, such as the shuttling of polysulfide intermediates, the large volume expansion of sulfur during charge/discharge and the dendrites formation on Li-anode. In this talk, we will introduce our recent investigation about Li-S batteries, including physical and chemical immobilization of sulfur to improve cycling stability, segregator optimization to minimize the shuttling effect and design of ionic liquids based electrolyte system to reduce the self-discharge. Finally, we introduce a lithium-ion sulfur battery based on a Li2S cathode using a dual-phase electrolyte (Li2S/electrolyte-1/LISICON/electrolyte-2/Li) and then replaced the Li anode with Al and graphite, which demonstrates a proof of concept of metal Li free Li-ion Sulfur battery.

Reference

[1] S.Y. Yuan, Z.Y. Guo, L.N. Wang, S. Hu, Y. G. Wang*, Y.Y. Xia*, Adv. Sci.
2015, 2: 1500071.

[2] S.Y. Yuan, J.W. Bao, L.N. Wang, Y.Y. Xia, D.G. Truhlar*, Y.G. Wang*, Adv. Energy Mater., 2015
, 1501733.

[3] L.N. Wang, J.Y. Liu, S. Haller, Y.G. Wang*, Y.Y. Xia*, Chem. Commun.,
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[4] L.N. Wang, J.Y. Liu, S.Y. Yuan, Y.G. Wang*, Y.Y. Xia*, Energy Environ. Sci.,
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[5] L.N. Wang, Y.G. Wang*, Y.Y. Xia*, Energy Environ. Sci.,
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First Principles Studies of Fe, Co, Mn, and Ir-Based Hybrid Li-Ion/Li-Oxygen Battery Materials
Authors: Li Liang , Kinaci Alper , Ford Denise , Letchworth-Weaver Kendra , Chan Maria K. Y.
Published: February 2020

In the Center for Electrochemical Energy Science (CEES) Energy Frontier Research Center, we are investigating a new class of energy storage materials – hybrid Li-ion/Li-oxygen materials – that combine transition metal and oxygen redox chemistries to deliver high energy storage capacity [1, 2, 3]. The electrochemical reactions, structural and electronic structure evolution of these materials are complex, requiring a combination of in-depth characterization and first principles modeling. In this talk, we will report on a comparison study of several examples of hybrid Li-ion/Li-oxygen materials using density functional theory calculations. We will discuss the structural, thermodynamic, and electronic structure reasons for differences in reaction pathways and competition between transition metal vs oxygen redox chemistries. Insight towards selecting and designing promising hybrid battery materials gleaned from the comparison will be discussed.

References

[1] L. Trahey, C. S. Johnson, J. T. Vaughey, S.-H. Kang, L. J. Hardwick, S. A. Freunberger, P. G. Bruce, M. M. Thackeray, “Activated Lithium-Metal-Oxides as Catalytic Electrodes for Li-O2 Cells,” Electrochemical and Solid-State Letters, 2011, 14, A64.

[2] M. M. Thackeray, M. K. Y. Chan, L. Trahey, S. Kirklin, and C. Wolverton, “Vision for Designing High-Energy, Hybrid Li Ion/Li–O2 Cells,” Journal of Physical Chemistry Letters, 2013, 4, 3607.

[3] Z. Yang, L. Trahey, Y. Ren, M. K. Y. Chan, C. Lin, J. Okasinski, and M. M. Thackeray, “In-Situ High-Energy Synchrotron X-ray Diffraction Studies and First Principles Modeling of α-MnO2 Electrodes in Li-O2 and Li-ion Coin Cells,” Journal of Materials Chemistry A, 2015, 3, 7389.

Acknowledgement

This work was supported as a part of the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under award number DE-AC02–06CH11. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Potassium Ion Cells Using Graphite Electrodes
Authors: Chun Guk Park
Published: February 2020

Graphite is known to be reliable anode materials in Li-ion batteries (LIBs). Graphite also has been studied as a cathode material in LIBs. As the requirement of development of next-generation batteries, however, graphite is also seeking for its use in a new system. The work using graphite in potassium ion batteries (KIBs) was triggered by the finding that potassium ions could be intercalated into graphite, in contrast to sodium ions. Graphite can also be used as a cathode in KIBs. When used as a cathode, the cations in electrolytes are intercalated into the anode, and the graphite cathode stores the anions of electrolytes. The process is reversed during the discharge step. However, the graphite is oxidized at high voltages (>5.0 V vs. K/K+), which requires the careful selection of electrolytes. The electrolyte not only needs to be electrochemically stable at high potentials, but also to form stable SEI on an anode surface. In this study, electrolyte systems prepared with various solvents were investigated at a high voltage limit for a graphite cathode half-cell using electrochemical methods. The safe voltage operation range and the suitable solvent were identified. The formation of SEI layer on the graphite anode surface was investigated using XPS analysis. Based on these results, we are trying to construct a symmetrical full cell using graphite as the active materials.
In Operando X-Ray Imaging and Tracking of Degradation and Failure Phenomena inside Zinc-Air Systems
Authors: Yufit Vladimir , Tariq Farid , Eastwood David S , Biton Moshiel , Wu Billy , Lee Peter D , Brandon Nigel P.
Published: February 2020

In search for the next generation of battery technology, rechargeable aqueous zinc-air systems present very attractive power sources due to high specific energy, safety, environmental compatibility and low cost of components and active materials. Nonetheless these systems have not yet been commercialised as they suffer from a short cycle life that prohibits their use for large electrical storage applications that require thousands of deep discharge cycles. One of the key factors responsible for shortened cycle life is dendritic growth occurring during the system charge. Dendrites can grow sufficiently wide to cause an internal short-circuit between the anode and the cathode. While extensive work has been carried out to study and mitigate zinc dendrite formation; real time dendritic growth mechanisms remain poorly understood

X-ray micro/nano tomography methods can provide unique insights into operation, degradation and failure of electrochemical energy storage and generation devices and systems. We implemented synchrotron x-ray tomography to investigate the mechanism and kinetics of dendrite formation and dissolution during zinc-air system operation. The dendrite growth and dissolution was analysed in-operando in radiography mode while three-dimensional characterisation of dendrites on top of the zinc electrode was carried out based on set of reconstructed multiple tomographic projections (Figure 1). Additionally individual dendrites have been analysed by high resolution FIBSEM. As such, an ability to actively track the mechanisms of growth and dissolution of dendrites form a critical basis if we are to extend the cycle life of metal-air batteries.

Figure 1
Phosphide-Based Nanocomposites As High-Performance Anode Materials for Na-Ion Batteries
Authors: Hong Kyung-Sik , Nam Do-Hwan , Lim Sung-Jin , Sohn DongRak , Kim Tae-Hee , Kwon HyukSang
Published: February 2020

Recently, Li-ion batteries are widely used as energy sources for portable devices and electric vehicles. However, the price of Li sources is expected to rise due to the increase in the Li demand. Na-ion batteries are considered as promising energy sources for large-scale systems because of the great abundance and the low cost of the Na sources. For the anodic Na storage materials, phosphorus has great potential due to the highest theoretical capacity, the low cost, and non-toxic nature of the raw materials. However, all the previous reports on phosphorus-based materials were not able to utilize fully their theoretical Na storage capacity (2596 mAh/g) and showed poor rate capability because of low electrical conductivity.

Herein, to solve this problem, we employed reducing particle size and designing a composite with conductive carbon by simple mechanical ball-milling method. The as-obtained tin phosphides, red phosphorus and carbon nanocomposites delivered a reversible charge capacity of 1266.8 mAh/g at the current density of 300 mA/g. Moreover, the electrode exhibited superior rate capability with a stable capacity of 426.9 mAh/g at the current density of 7500 mA/g. The improved electrochemical performances resulted from the nanosized tin phosphide particles reducing the diffusion length of the sodium ions and amorphous red phosphorus/carbon matrix effectively buffering the volume expansion during the cycling.

Figure 1
RuO2/MnO2 Nanorods As High Efficient Electrocatalyst of Lithium-Oxygen Battery
Authors: Xu Yue-Feng , Xu Gui-Liang , Zhang Xiao-Ru , Chen Yuan , Chen Zonghai , Huang Ling , Li Jun-Tao , Amine Khalil , Sun Shi-Gang
Published: February 2020

Electrocatalyst is the key component in Li-O2 batteries and attracted extensive attention in recent years. It has demonstrated that carbon materials1, transitional metal oxides2, noble metals3, and Perovskite-type oxides4 can present high catalytic activity in oxygen reduction reaction (ORR) or in oxygen evolution reaction (OER) to facilitate decomposition of Li2O2. In order to explore high efficient electrocatalyst, in the present work, RuO2/MnO2 nanorods were synthesized via a facile two-step hydrothermal reaction. Li-O2 battery testing results demonstrated that the as-synthesized RuO2/MnO2 nanorods exhibit excellent properties as electrocatalyst of oxygen cathode. The RuO2/MnO2 nanorods could maintain a reversible capacity of 500 mAh g-1 in 75 cycles at a rate of 50mA g-1, and a higher capacity of 4000 mAh g-1 in 20 cycles at a rate of 200mA g-1. Moreover, the RuO2/MnO2 nanorods present a much lower voltage polarization in charge/discharge processes than MnO2 nanorods electrode does. The catalytic activities of RuO2/MnO2 nanorods and MnO2 nanorods were also compared by studies of rotating disk electrode (RDE). Furthermore, in situ high-energy X-ray diffraction and ex situ SEM were carried out to investigate the formation and decomposition of the discharge products Li2O2.

Figure 1. (a)(b) In-situ XRD patterns of the electrode in discharge process for 20 h. (c) Charge/discharge curves of RuO2/MnO2 nanorods at a rate of 50 mA g-1.

ACKNOWLEDGMENT: This work was financially supported by NSFC (Grant Nos. 21373008, 21321062, 21273184)

REFERENCES:

(1) Liu, T.; Leskes, M.; Yu, W.; Moore, A. J.; Zhou, L.; Bayley, P. M.; Kim, G.; Grey, C. P., Science 2015, 350, 530-533.

(2) Zhang, P.; Sun, D.; He, M.; Lang, J.; Xu, S.; Yan, X., ChemSusChem 2015, 8, 1972-1979.

(3) Bruce, P. G., Science 2012, 337, 563-566.

(4) Xu, J. J.; Xu, D.; Wang, Z. L.; Wang, H. G.; Zhang, L. L.; Zhang, X. B., Angewandte Chemie 2013, 52, 3887-90.

Figure 1
Cycling Performance of Lithium-Oxygen Batteries Assembled with Hybrid Electrolytes
Authors: Woo Hyun-Sik , Kim Jae-Hong , Kim Dong-Won
Published: February 2020

Rechargeable lithium-oxygen batteries that utilize oxygen have attracted great interest as next-generation energy storage systems due to their high theoretical specific energy (11,140 Wh kg-1 when excluding oxygen weight), which exceeds that of any other rechargeable battery system.1,2 A non-aqueous lithium-oxygen battery typically consists of a lithium negative electrode, an organic liquid electrolyte, and a porous carbon positive electrode so as to induce the oxygen electrochemical reaction. Among these battery components, the electrolyte has been recognized as one of the greatest challenges facing the successful development of non-aqueous lithium-oxygen batteries.3 In this study, we investigated hybrid electrolyte composed of polymer, Li+-ion conducting inorganic electrolyte and organic liquid electrolyte. The hybrid electrolyte effectively suppressed lithium dendrite growth and prevented evaporation of organic liquid electrolyte under semi-open conditions. Moreover, the Li+-ion conducting inorganic electrolyte was very stable from superoxide anion radical attack, which led to significant improvement of cycling stability. The cycling performances of lithium-oxygen batteries assembled with these hybrid electrolytes are investigated and will be presented.

 

References

1. K. M. Abraham and Z. Jiang, J. Electrochem. Soc., 143, 1 (1996).

2. Z. Q. Peng, S. A. Freunberger, Y. H. Chen and P. G. Bruce, Science, 337, 563 (2012).

3. J. Lu, L. Li, J. B. Park, Y. K. Sun, F. Wu and K. Amine, Chem. Rev., 114, 5611 (2014).