bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Silicon-Graphene Anodes for High Performance Applications
Authors: Hayner Cary , Lau Joshua , Ha Seonbaek , McKinney James , Wang Francis P. , Mayekar Samir
Published: February 2020

Rechargeable batteries with improved energy and power density have many potential, high impact applications including advanced portable electronics and electric vehicles.  However, most ‘next-generation’ materials capable of providing improved performance suffer from rapid capacity degradation or severe loss of capacity when rapidly discharged. 

Silicon is a promising anode material that is widely investigated as a potential successor for graphite since it can store significantly more energy per mass and volume.  Tremendous advancement towards commercialization of silicon anodes – including improving cycle life and minimizing electrode swelling – has been made over the past decade.  Proper electrode engineering has brought silicon-based anode materials closer to commercialization into consumer applications.  However, cycle life and irreversible capacity losses (ICL) due to side reactions continue to be issues that plague their widespread use.  However, silicon technology has not yet been significantly commercialized due to a number of shortcomings. 

Graphene, an atomically thin version of graphite widely regarded as a wonder material, has the potential to overcome many of the remaining issues due to graphene’s unique combination of high surface area, high in-plane electrical conductivity, excellent tensile modulus and mechanical durability.  In this presentation, we will describe the approaches and architectures employed using silicon-graphene composites to accelerate their development as well as remain challenges to be solved. 

SiNode Systems is a battery materials venture developing silicon-graphene anodes for the next generation of lithium-ion batteries. SiNode anodes offer higher battery capacity and faster charging rates, all while being produced via a low cost solution chemistry-based manufacturing process.  SiNode seeks to change the landscape for lithium-ion batteries so they can meet the demands of a wide range of industries, from consumer electronics to electric vehicles.
High Energy Lithium Ion Batteries Based on Cobalt Rich Composite Cathode and Silicon Anode
Authors: Kumar Sujeet
Published: February 2020

Batteries are the main limitation to the wide spread adoption of electric vehicles and plug in hybrids.  Battery energy density must be improved to increase EV driving range and lower battery cost.  State of the art high energy lithium batteries use NCA cathode and graphite anode e.g. cylindrical 18650 cells that can provide specific energy up to 250 Wh/kg.  Replacement of graphite with silicon based anode is mandatory to further boost specific energy.  However, cells with silicon based anode have poor cycle life and very high swelling.  Proper selection of cathode is also important to attain high energy density when paired with Silicon based anode.  Although the capacity of Si-based anode materials are high, their intercalation potential is much higher than that of Li or graphite which translates to a lower overall cell voltage (at least 0.4V lower) resulting in lower energy density.  A high capacity and high average voltage cathode is required to compensate the overall drop in the average voltage.

In this work, Cobalt-Rich Composite (CRC) cathode has been developed that also contains significant amount of Nickel and Manganese. The resulting CRC cathode shows stable high voltage performance compared to LCO. Traditionally the structure of LCO cathode degrades at high charge voltages (>4.4V) when >0.5 moles of Li are extracted from the structure. The CRC cathode enables high electrode active content (>97%) and high electrode density (>4.0g/cc), high average voltage (3.95V) and high specific capacity (>190 mAh/g in half cell). Most importantly, CRC cathode does not exhibit any voltage fade upon cycling at higher voltages (>4.45V) as observed in lithium rich manganese rich composite cathode.  

CRC cathode has been complemented with a high capacity SiOx-based anode electrode in a high energy cell. Typical commercially available Si-based materials suffer from large volume expansion resulting in pulverization and poor cycle life. We present high capacity SiOx-based anode (>1400 mAh/g) electrodes with high percent active content (>80%) that has shown to cycle over 500 times.  A novel anode fabrication approach has been used taking advantage of a high strength binder, carbon nanotube network and pre-lithiation.  Swelling, cycling and abuse testing results of the cells will be presented. Figure 3 shows 10Ah capacity pouch cells integrating CRC cathode and SiOx anode with specific energy of ~350Wh/Kg. The cells show excellent rate capability as required for automotive and drone applications. There is significant energy above lower cut off voltage 3.0V required by consumer electronic devices. This presentation will also cover remaining challenges associated with CRC cathode and SiOx anode with respect to synthesis, performance and cell manufacturing.

Figure 1
Advnaced Silicon and Tin Anodes for Lithium Ion Battery
Authors: Chen Zhongwei , Yu Aiping
Published: February 2020

Development of low cost, high energy, safe and long-life rechargeable battery technology is critical for widespread commercialization of smart grid and electric vehicle. Rechargeable lithium-ion batteries have been considered as most promising candidates as energy storage system for transportation, smart grids and stationary power. In this presentation, I will present our recent work on advanced Silicon(Si) and Tin(Sn) anode materials development for next generation rechargeable lithium-ion batteries: (1) The latest achievements and some ongoing work in silicon anode based high energy Li-ion battery through the collaboration with General Motors. More specifically, advanced Si electrodes have been developed by a simple flash heat treatment and sulfur-doped graphene wrapping technique which can efficiently accommodate Si volume expansion and demonstrate excellent electrochemical reversibility and cycling. (2) A novel and facile method was developed to synthesize a rod-on-sheet-like nanohybrid (denoted as SnS-SG), consisting of one-dimentional (1D) single-crystalline, orthorhombic tin sulfide (SnS) supported on two-dimentional (2D) sulfur-doped graphene. The SnS-SG nanohybrid exhibited a superior cycle stability over 1500 cycles with a high capacity retention of 85%, the longest demonstrated cyclability among numerous Sn-based anode materials reported so far in LIBs.
Insights into Limited Cycling Performance of Li2fe(SO4)2 in the Presence of Polvinylidene Fluoride Binder
Authors: Muthiah Aravind , Baikie Tom , Shukla Shashwat , Ball Sarah , Copley Mark , Hyde Timothy , Sankar Gopinathan , Srinivasan Madhavi
Published: February 2020

Fe-based high voltage positive electrode material Li2Fe(SO4)2 has shown consistent cycling only in experimental Swagelok cell configurations.[1, 2] In order for it to be practically viable, knowledge of its interaction with commercially used additives in the coating process is lacking.  Thus, this report seeks to study the cycling performance of Li2Fe(SO4)2 in a half cell configuration in coin cells as a step towards commercial utilization of the material.

Marked degradation of cycling performance of Li2Fe(SO4)2 was observed in the coin cell configuration in comparison to the consistent cycling in a Swagelok cell. To investigate this performance degradation, the coin cell electrodes were subjected to ex-situ X-ray Fine Absorption Structure (XAFS) analysis. The X-ray Near Edge Absorption Structure (XANES) data showed no change in oxidation state of Fe in contrast to in-situ studies on the Swagelok cell done earlier.[1] However, the Extended X-ray Fine Absorption Structure (EXAFS) analyses yielded permanent changes in Fe-O bond lengths from 2.088 Å for a fresh electrode to 2.076 Å after one full cycle indicating structural changes in the system. The shorter Fe-O bond length is more covalent [3] resulting in the intercalation of the second cycle occurring at a lower redox potential and causing the material to lose its high voltage characteristic.

The structural changes were attributed to the reactivity of the sulphate electrode material with the fluorine in the commercially used polvinylidene fluoride (PVDF) binder used to coat the electrodes. This reactivity has a larger implication of incompatibility of fluoride ions with sulphate based materials and therefore necessitates the use of alternate non-fluorinated binders and electrolytes for their consistent performance.

References:

[1]        M. Reynaud, M. Ati, B. C. Melot, M. T. Sougrati, G. Rousse, J.-N. Chotard, et al., "Li2Fe(SO4)2 as a 3.83 V positive electrode material," Electrochemistry Communications, vol. 21, pp. 77-80, 2012.

[2]        L. Lander, M. Reynaud, G. Rousse, M. T. Sougrati, C. Laberty-Robert, R. J. Messinger, et al., "Synthesis and electrochemical performance of the orthorhombic Li2Fe(SO4)2 polymorph for Li-ion batteries," Chemistry of Materials, vol. 26, pp. 4178-4189, 2014.

[3]        A. Gutierrez, N. A. Benedek, and A. Manthiram, "Crystal-Chemical Guide for Understanding Redox Energy Variations of M2+/3+ Couples in Polyanion Cathodes for Lithium-Ion Batteries," Chemistry of Materials, vol. 25, pp. 4010-4016, 2013.
Mechanical Properties of Solid Electrolyteinterphase Layer in Li-Ion Batteries: Experimental and Computationalstudies
Authors: Shin Hosop , Lu Wei , Park Jonghyun
Published: February 2020

The mechanical instability of the Solid Electrolyte Interphase (SEI) layer in lithium ion (Li-ion) batteries causes significant side reactions resulting in Li-ion consumption and cell impedance rise by forming further SEI layers, which eventually leads to battery capacity fade and power fade. In this work, the SEI elasticity was studied both experimentally and computationally. To characterize the SEI elasticity, the SEI layer formed on a HOPG electrode in a LiPF6 / EC+DMC electrolyte has been investigated using PF-QNM and atomistic calculations. Both experimental and computational results have shown that SEI elasticity is strongly affected by the SEI chemical composition. It was observed that the inner layer is stiffer than the outer layer. The measured Young’s moduli were mostly in the range of 0.2 to 4.5 GPa, while some values above 80 GPa were also observed. This wide variation of the observed elastic modulus was elucidated by atomistic calculations with a focus on chemical and structural analysis. The numerical analysis showed the Young’s moduli ranged from 2.4 GPa to 58.1 GPa in the order of the polymeric, organic, and amorphous inorganic components. The crystalline inorganic component (LiF) showed the highest value (135.3 GPa) among the SEI species. This quantitative observation on the elasticity of individual components of the SEI layer must be essential to analyzing the mechanical behavior of the SEI layer and to optimizing and controlling it. The findings from this work can be used in controlling the SEI layer to minimize damage to the SEI layer. The mechanical stability (adhesion, elasticity, etc.) of the SEI layer can be achieved by changing formation conditions and electrolytes (salts, solvents, and additives). For instance, the formation of an inorganic layer with an amorphous feature, and of a PEO polymeric layer rather than an EC- or DMC-based organic layer would be desirable for forming a flexible SEI layer.
Probing the Limits of Electron and Ion Transport over Multiple Length Scales
Authors: Takeuchi Esther S , Bock David C , Pelliccione Christopher J , Zhang Wei , Knehr Kevin W , Brady Nicholas W , Cama Christina A , Lininger Christianna Naomi , Kirshenbaum Kevin , Wang Jiajun , Wang Jun , Li Yan , West Alan C , Wang Feng , Marschilok Amy C , Takeuchi Kenneth J
Published: February 2020

As the demand for large scale batteries has grown, considerations such as earth abundance, cost, and toxicity have assumed a greater significance.  Metal oxides such as magnetite (Fe3O4) are worthy of evaluation as active materials for electrochemical energy storage due to its earth abundance, low cost, environmentally benign iron metal centers and high theoretical capacity, 926 mAh/g.  Implementation in the future will require understanding of the fundamental electrochemical reduction-oxidation mechanisms of the electroactive materials is required, coupled with characterization at the mesoscale to understand the underlying contributors to localized resistance which must be addressed in order to achieve significant improvements to current capability and reversibility.

An emerging paradigm for the implementation of close-packed materials in higher current applications is the tuning of the materials crystallite dimensions, where the reduction of crystallite size should minimize the path length for ion transport upon discharge, resulting in a reduction of both internal cell resistance and the resultant structural strain associated with lithium insertion.  The electrochemical impact of controlled crystallite size of magnetite will be described.

In addition to the crystallite size of the electroactive material, a complete study of an electroactive nanomaterial in the complex mesoscale environment of a composite battery electrode should also consider the level of electroactive particle agglomeration, and agglomerate distribution within the battery electrode.  Nanocrystalline magnetite (Fe3O4) powders and composite electrodes with different crystallite sizes were prepared, characterized, and electrochemically evaluated.  Transmission electron microscopy (TEM) examination of cross-sectioned electrodes was used to quantify the aggregate size of the Fe3O4 active material.  Notably, although the crystallite sizes of two magnetite samples Fe3O4 are different (28 and 9 nm), the observed sizes of the aggregates and aggregate distribution within the electrodes were similar, see TEM images of sectioned electrodes fabricated with the 28 nm (A,B) and 9 nm (C,D) sized Fe3O4 in the Figure.  Transmission x-ray microscopy (TXM) combined with x-ray absorption near edge spectroscopy (XANES) at the National Synchrotron Light Source (NSLS) were used to determine the distribution of the iron oxidation states within the electrodes before and after electrochemical testing.  The impact of both crystallite size and agglomeration on electrochemical performance were assessed.

Figure 1
Electrochemical Performance of Cation Doped LiFePO4/Grephene Composites
Authors: Fang Hui , Sanchez Cassidy
Published: February 2020

Cation doped LiFePO4/graphene composites with dopant Ti, Zr, or Nb were prepared by solid-state reaction. The as prepared composites were characterized by X-ray diffraction and scanning electron microscopy. Their electrochemical properties were investigated by cycling charge and discharge measurements at various C-rate, cyclic voltammetry, and electrochemical impedance spectroscopy. The experimental results reveal the combined effects brought by cation doping and graphene addition on LiFePO4.
One-Dimensional Nanomaterials for Energy Storage
Authors: Mai Liqiang
Published: February 2020

One-dimensional nanomaterials can offer large surface area, facile strain relaxation upon cycling and efficient electron transport pathway to achieve high electrochemical performance. Hence, nanowires have attracted increasing interest in energy related fields.

  To increase the stability of Li-ion battery, V3O7 nanowire templated semi-hollow bicontinous graphene scrolls architecture is designed and constructed through “oriented assembly” and “self-scroll” strategy. The V3O7 nanowire templated semi-hollow bicontinous graphene scrolls with interior cavities provide continuous electron and lithium ion transfer channel and space for free volume expansion of V3O7 nanowires during cycling, thus representing a unique architecture for excellent lithium ion storage capacity and cycling performance. Besides, we have designed and synthesized hierarchical MnMoO4/CoMoO4 heterostructured nanowires by combining "oriented attachment" and "self-assembly". The asymmetric supercapacitors based on the hierarchical heterostructured nanowires show a high specific capacitance and good reversibility with a cycling efficiency of 98% after 1,000 cycles. Recently, we also constructed the hierarchical zigzag Na1.25V3O8 nanowires, K3V2(PO4)3 bundled nanowire, and Li3V2(PO4)3 mesoporous nanotubes with enhanced electrochemical performance. Our work presented here can inspire new thought in constructing novel one-dimensional nanostructures and accelerate the development of energy storage appilications.
Growth Mechanisms in High-Rate Lithium Metal Batteries
Authors: Bai Peng , Wang Miao , Brushett Fikile R. , Bazant Martin Z.
Published: February 2020

Lithium metal anode is the key for the next-generation high-energy batteries. But lithium dendrites formed during recharge (electrodeposition at the anode) could short-circuit the battery and lead to fires and explosions. Tremendous efforts have been devoted to modify the composition of electrolytes and the surface of lithium electrodes, but mainly improved the stability of lithium under small currents and low capacities. Here, we devise a Li symmetric cell in a fine glass capillary, and the in situ observations reveal that the morphology of lithium deposit changes from a dense porous (mossy) structure to needle-like (dendritic) structure at Sand’s time, when the concentration of electrolyte decreases to zero at the surface of the electrode. Further experiments in sandwich cells of Li|Separator(Electroylte)|Li confirm that mossy lithium can be completely blocked by anodic aluminum oxide (AAO) membrane until Sand’s time, when a sudden voltage jump stimulates dendritic lithium to form, penetrate the nanopores of AAO and then short the cell, just like the behavior of transport-limited dendritic growth of copper. By creating a free compartment on each side of the AAO membrane, our sandwich cells can stably cycle at much higher current densities and capacities, e.g. at 5mA/cm2 for 5mAh/cm2. Our results agree well with a current-dependent critical capacity, C
Sand~ADc0
2/I, which suggests that increasing the concentration of electrolytes c
0 or lithium ion diffusivity D, and tuning the property of SEI to maintain a relatively large active surface area A of the porous lithium are beneficial to engineering rechargeable high-rate and large-capacity lithium metal anode.

Figure: Single dendrite shoots out from the mossy lithium deposits at Sand’s time, indicating a change of growth mechanism.

Figure 1
Study the Interface of Cathode Material and Li-La-Zr-O Thin Film Prepared at Low Temperature for All Solid State Li Battery
Authors: Zarabian Mina , Perez-Zurita Maria Josefina , Buyukaksoy Aligul , Pereira-Almao Pedro , Thangadurai Venkataraman
Published: February 2020

Switching from an organic polymer-based Li ion electrolyte to a ceramic Li ion electrolyte is expected to allow for the higher energy density, improve the safety and cycle lifetime. These, all solid state Li ion batteries can also be miniaturized, which will streamline the packing design. Among studied Li ion conductive solid electrolyte (1, 2) garnet family have recently gained lots of attention due to the high ionic conductivity and electrochemical stability at ambient temperature. Garnet-like structure, Li7La3Zr2O12 (LLZO) has shown comparable Li ion conductivity with the current Li ion electrolytes (3). However, the reported ionic conductivity of a thin film LLZO was three orders of magnitude lower compared to bulk phase (4). The main goal of the current research is to develop thin film solid electrolyte on the LiCoO2 electrode and investigate the interface. For this purpose, LLZO was fabricated using a liquid precursor technique. The Li-La-Zr nitrate solution was coated on the top surface of the LiCoO2 substrate for several times until the appropriate thickness (300 nm – 1 µm) is obtained. After each step of coating, the deposited precursor is dried and decomposed at 450 °C. Figure 1 shows cross section image of crack-free, flat, dense and homogenous solid electrolyte layer deposited on the surface of the LiCoO2. X-ray photoelectron spectroscopy (XPS) coupled with ion etching is used to understand the interface composition and thickness. Electrochemical impedance spectroscopy (EIS) was used to analyze and understand the electrolyte and interfacial resistance. 

References

1.            S. Teng, J. Tan and A. Tiwari, Current Opinion in Solid State and Materials Science, 18, 29 (2014).

2.            V. Thangadurai, D. Pinzaru, S. Narayanan and A. K. Baral, The Journal of Physical Chemistry Letters, 6, 292 (2015).

3.            R. Murugan, V. Thangadurai and W. Weppner, Angewandte Chemie International Edition, 46, 7778 (2007).

4.            K. Tadanaga, H. Egawa, A. Hayashi, M. Tatsumisago, J. Mosa, M. Aparicio and A. Duran, Journal of Power Sources, 273, 844 (2015).

Figure 1
High Voltage Operation of Surface Coated NMC in Ionic Liquids Based on 1-Ethyl-3-Methylimidazolium Bis(fluorosulfonyl)Imide
Authors: Matsumoto Hajime , Taguchi Noboru , Sakaebe Hikari , Tatsumi Kuniaki , Ogumi Zempachi
Published: February 2020

Ionic liquids (ILs) have been studied as a unique electrolyte for a lithium battery for a past two decades 1).  The thermal stability and less-volatility have been expected to improve safety of a conventional lithium ion battery system using flammable non-aqueous electrolytes. For example, using bis(trifluoromethylsulfonyl)imide (TFSA-) –ILs as a electrolyte, LiFePO4 half cell could be charged and discharge over 100 °C 2).

 In this study, we will report that another unique and important features of a zero-solvent electrolyte like ILs was indicated at a high voltage (> 4.7 V) charging and discharging cycle using a transition metal oxide cathode as a LCO and NMC. A modification of NMC by coating with Al2O3 particle successfully improved the high voltage operation over 4.2 V as already reported 3). However, we found that a LCO and also NMC cathode without any coating could be stable over 4.7 V charging and discharging cycle even in 1-ethyl-3-methylimidezolium bis(fluoromethylsulfonyl)amide ([EMI][FSA]) containing a certain amount of Li[FSA]. This finding indicate that a catalytic site for oxidation decomposition of a conventional organic electrolyte on a transition metal oxide, which was deactivate by a surface coating with Al2O3, did not affect the oxidation of the ionic liquids electrolyte, which did not contain any organic solvents. On the other hand, a cycle stability at a high temperature over 45 °C was effectively stabilized by a surface coating on NMC with ZrO2. The result implies that the surface modification of a transition metal cathode effectively protected the structural disorder of a cathode material by a high temperature condition.

These results show that using zero-solvent electrolyte like ILs might be a useful tool to elucidate the effect of surface modification in an organic solvent electrolyte.

Acknowledgment

This work was supported by the “Research & Development Initiative for Scientific Innovation of New Generation Batteries (RISING)” project of the New Energy and Industrial Technology Development Organization (NEDO).

1)    H. Matsumoto, in Electrolytes for Lithium-ion Batteries, eds. T. R. Jow, K. Xu, O. Borodin and M. Ue, Springer, 2014, ch.4. 

2)    H. Matsumoto and K. Kubota, ECS Transactions, 64(4), 425 (2014).

3)    K. Araki, N. Taguchi, H. Sakaebe, K. tatsumi, Z. Ogumi, J. Power Sources, 269 (2014) 236.
In Situ Neutron Diffraction Studies of Ion Exchange - Application to Solid State Electrolytes
Authors: Khalifah Peter , Liu Jue , Whitfield Pamela , Saccomanno Michael , Hu Enyuan , Yu Xiqian , Bai Jianming , Yang Xiao-Qing
Published: February 2020

In situ neutron diffraction is for the first time demonstrated to be a powerful tool for precisely following the structural changes associated with mobile light ions during Li+/Na+ ion exchange.  While ion exchange is traditionally accomplished using a liquid electrolyte, the present experiments were facilitated by the use of non-molten salts as the source of ions.  A novel isotropic Li-ion conductor was investigated in the present work. High quality structural data could be obtained through the Rietveld refinement of neutron diffraction data collected with ~30 minute time steps.  The mechanism of ion exchange could be readily resolved from this data, including the identification of a hidden phase transition not apparent from studies of the lattice parameters along, the identification of site-specific contributions to the overall volume change during ion exchange, and the observation of different equilibrium ratios of phases at different temperatures.  This method should have general applicability to the study of ion exchange processes in solids, but provides the most advantages for the study of oxide ceramics due to the high sensitivity of neutrons to oxygen and other light elements.
Charge Transfer Catalysis Across Semiconductor/Electrolyte Interfaces By Metalloporphyrin/Polymer Matrices
Authors: Hilal Hikmat S. , Zyoud Ahed H.
Published: February 2020

Polycrystalline metal chalcogenide (CdS, CdSe, CdTe, CuS, CuSe and others) thin-film electrodes are being considered as alternative for the more costly and advanced-tech demanding photovoltaic (PV) systems. Despite their ease of preparation and economy in starting materials, the thin film electrodes have major drawbacks. Due to lack of surface uniformity, low carrier mobility and high resistance at the solid/liquid interface, such electrodes exhibit low conversion efficiency in PEC processes. Moreover, the electrode surfaces are unstable and tend to undergo photo-corrosion.  These shortcomings are a real challenge for using thin film electrodes in PEC technology, and should be overcome.     Porphyirinato manganese (MnTPyP) complexes embodied inside different polymeric materials have been used as charge transfer mediators across solid/liquid junctions in PEC processes.    The MnTPyP/Polymer coating (~80 nm thick) can be cast onto surfaces of the polycrystalline metal chalcogenide thin film electrodes in simple methods.  The coating showed remarkable enhancement in the PEC conversion efficiency of different electrodes.  Both short-circuit current and fill factor values have been remarkably enhanced.  Conversion efficiency values of as high as 19% have been observed here.  Such results have not been preceded before in metal chalchogenide thin-film electrode processes.  Moreover, the coating enhanced the semiconductor electrode stability to photo-corrosion under PEC conditions.  The MnTPyP/Polymer matrix behaved as charge transfer mediator across the solid/liquid interface.  Upon exciting an n-type semiconductor electrode, electrons are excited from the valence band to the conduction band and move to the back contact wiring. The remaining holes must move to the redox couple to make photo-current. In polycrystalline semiconductor electrodes, such a transfer is not fast enough, which lowers the value of the short circuit current, and consequently the conversion efficiency.  Therefore, holes accumulate in the space charge layer and cause electrode corrosion.  The MnTPyP/Polymer matrix enhances both efficiency and stability of the electrode by behaving as a charge transfer mediator.  The MnTPyP complex involves both MnIII and MnII ions together.  The holes in the valence band oxidize the MnII ions into MnIII ions. The MnIII ions in turn oxidize the reduced phase of the redox couple.  By this way, the MnTPyP complex catalyzes the hole-transfer and enhances both efficiency and stability of the electrode.  The charge transfer mediation formalism is summarized in the attached Scheme.   Results and discussions will be presented in detail together with effect of the coating on the electrode band edge positions.

Figure 1
Composite Solid Polymer Electrolyte Membrane
Authors: Wang Ting , Xie Jingying , Wang Jiulin , Wang Ke
Published: February 2020

Due to safety issues in the lithium batteries with organic liquid electrolytes, it is expected that the next-generation safe lithium batteries would be the all-solid-state batteries. New solid electrolytes with high Li+ ion conduction such as Li10GeP2S12, Li1.3Al0.3Ti1.7(PO4)3 and Li7La3Zr2O12 have attracted extensive attentions in the development of solid-state batteries. Especially, the garnet-type material Li7La3Zr2O12 has several advantageous properties such as good thermal and chemical stability with lithium metal anode, environmental compatibility, relatively high Li+ion conductivity. However, the poor contact between electrodes and electrolyte is a most important factor limiting the development of LLZO all-solid-state battery.

     So we combining P(VDF-HFP) polymer electrolyte and LLZO powder and painting it on the fiberglass to construct composite solid polymer electrolyte. The SEM micrographs of the with 30wt% LLZO added are shown in Fig.1. There are obvious powder have attaching to the fiberglass surface and the polymer on it. Fig.2. compared rate capability of the composite solid polymer electrolyte film and the fiberglass. Founding that the composite system can obviously increasing it.

Fig.1 SEM micrographs of the
composite 
solid polymer electrolyte. 

Fig.2 Rate capability of the composite solid
 polymer electrolyte film and the fiberglass.

Acknowledgements

The project was supported by the National Natural Science Foundation of China (21373137), Shanghai Science and Technology Development Fund (15DZ2282000) and the Foundation of China (NSFC21373137).

Figure 1
Reduction Products of Vinylene Carbonate and Fluoroethylene Carbonate
Authors: Subramanian Parimalam Bharathy , Nie Mengyun , Lucht Brett L
Published: February 2020

Lithium ion batteries play an important role as energy storage devices in consumer electronics and electric vehicles, thanks to their high energy density, high efficiency and long life. Mixtures of organic carbonates are usually employed as electrolyte solvents in these batteries. Electrolyte reacts reductively with the anode and forms a passivation layer (SEI) during initial charging cycles. SEI layer plays a crucial role in the performance of a lithium-ion battery1 and small amount of additives are generally employed to improve the characteristics of the SEI. Understanding the reduction products of effective electrolyte additives would facilitate us to design better additives to improve the performance of lithium ion battery.  Vinylene carbonate and fluoroethylene carbonate are excellent additives. They improve the initial irreversible capacity and high temperature performance of the lithium-ion battery, when added to the electrolyte.2
,
3 Theoretical study on reduction of these additives indicates, they may yield very similar SEI.4 Lithium naphthalenide, a popular one-electron reducing agent, is shown to reduce the electrolyte similar to lithiated graphite anode.5 The same compound is utilized to reduce Vinylene carbonate & fluoroethylene carbonate. The products were analyzed with GCMS, NMR & FTIR and the results will be discussed. Acknowledgement

 The authors gratefully acknowledge funding from Department of Energy Office of Basic Energy Sciences

EPSCoR Implementation award (DE-SC0007074). References

(1)        R Fong, U von Sacken, J. D. 2009, 137 (7), 3–7.

(2)        Aurbach, D.; Gamolsky, K.; Markovsky, B.; Gofer, Y.; Schmidt, M.; Heider, U. Electrochim. Acta
2002, 47 (9), 1423–1439.

(3)        McMillan, R.; Slegr, H.; Shu, Z. .; Wang, W. J. Power Sources
1999, 81-82, 20–26.

(4)        Hoz, J. D. La; Balbuena, P. Phys. Chem. Chem. Phys.
2014, 1–18.

(5)        Nie, M.; Chalasani, D.; Abraham, D. P.; Chen, Y.; Bose, A.; Lucht, B. L. J. Phys. Chem. C
2013, 117 (3), 1257–1267.
Phase Transformations in Layered O and P Type Metal Oxide Na-Ion Battery Cathodes
Authors: Toumar Alexandra J. , Ong Shyue Ping , Richards William Davidson , Huang Wenxuan , Dacek Stephen , Ceder Gerbrand
Published: February 2020

Current state of the art Na-ion battery cathodes are selected from the broad chemical space of layered first row transition metal (TM) oxides. Unlike their lithium ion counterparts, seven first row layered TM oxides can intercalate Na ions reversibly. Their voltage curves also indicate significant and numerous reversible phase transformations during electrochemical cycling. These transformations are not yet fully understood, but arise from Na-ion vacancy ordering and metal oxide slab glide.

In this study, we investigate the nature of vacancy ordering transformations within the O3, P3 and P2 lattice frameworks. We generate predicted electrochemical voltage curves for each of the Na-ion intercalating layered single TM oxides using a high-throughput framework of density functional theory (DFT) calculations. We determine a set of vacancy ordered phases appearing as ground states in all Na\textsubscript{x}MO\textsubscript{2} systems, and investigate the effect of ordering interactions between adjacent layers. We further investigate the role of TM choice and TM mixing in mitigating phase transformations and synthesis of O3 and P2 type materials.
Electrochemical and Chemical Na+/Li+ Ion Exchange in Na-Based Cathode Materials
Authors: Kosova Nina V. , Tsapina Anna M. , Petrov Sergey A. , Slobodyuk Arseny B.
Published: February 2020

Sodium-based insertion materials are of interest for low-cost and large-scale Na- and Li-ion batteries. Substantial research effort has been invested during the previous years to produce electrode materials for sodium batteries that will allow for facile intercalation of Na-ions at suitable potentials. Amongst the cathode materials investigated, a variety of layered oxides (e.g. NaxCoO2, NaCrO2, NaVO2, Nax[Fe0.5Mn0.5]O2) and polyanionic compounds (e.g. NaFePO4, Na3V2(PO4)3, Na2FePO4F, NaFeSO4F) have been reported. The ability of these materials for facile Na+/Li+ ion exchange has been also revealed [1]. Recently, sodium vanadium fluorophosphates [2-5] and sodium iron pyrophosphate [6,7] have been examined and showed good electrochemical properties in Na-cells. The aim of the present work was to investigate electrochemical and chemical Na+/Li+ ion exchange in these materials.

Sodium vanadium fluorophosphates Na1+yVPO4F1+y (0≤y≤0.5) and sodium iron pyrophosphate Na2FeP2O7 were prepared by mechanochemically assisted solid state synthesis using high-energy AGO-2 planetary mill. The activated mixtures were subsequently heat treated at 600-700 °C in Ar flow. Structure and morphology of the as-prepared materials were analyzed by XRD with Rietveld refinement using GSAS and TOPAS software packages, SEM, FTIR, Mössbauer, 23Na and 31P MAS NMR spectroscopy. Electrochemical Na+/Li+ ion exchange was studied by galvanostatic cycling in Li+ cells with Li as an anode and LiPF6 dissolved in EC+DMC as an electrolyte. Non-oxidative chemical ion exchange was carried out in the solution of LiBr in acetonitrile for 24 h. Ex situ XRD, EDX, Mössbauer and NMR spectroscopy studies were carried out to control the phase and structural transformations. Structure of the as-obtained mixed Na/Li compositions was compared with that of the correspondent lithium compounds [8].

[1] N.V. Kosova, V.R. Podugolnikov, E.T. Devyatkina, A.B. Slobodyuk, Mater. Res. Bull. 60 (2014) 849.

[2] J. Barker, M.Y. Saidi, J.L. Swoyer, Electrochem. Solid-State Lett. 6 (2003) A1-A4.

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Reversible Sodium Storage Mechanism of Aromatic Diimide Disodium Carboxylates
Authors: Veerababu Medabalmi , Varadaraju U V , Ramanujam Kothandaraman
Published: February 2020

Sodium- ion batteries have attracted attention in recent times due to sodium is highly abundant and cost effective in comparison to lithium. However the traditional inorganic based electrode materials suffering due to the constraint imposed by their structural aspects and scarcity of resources. Hence researchers focus on alternative electrode materials which could be synthesized from renewable sources via eco-friendly processes [1]. Recently redox active organic materials have gained great interest in energy storage and conversion field, particularly Na-ion batteries due to their structural diversity, eco-friendly processability and resource renewability [2].  In this connection we report imide carboxylate based sodium salts namely, disodium N, N'-bis (glycinyl) pyromellitic diimide (Na2-BPDI) and disodium N, N'-bis (glycinyl) naphthalene diimide (Na2-BNDI) as electrode materials for Na-ion batteries for the first time. These compounds are easily synthesizable and most stable at ambient conditions.  Among two compounds Na2-BNDI delivered a stable reversible capacity of 122 mAh g-1
at a current density of 50 mA g-1 (Fig.1), where as a marginal capacity fading was observed upon cycling in the case of Na2-BPDI.  This capacity fading is due to change in unit cell volume followed by decomposition mechanism involved during the cycling and it is confirmed by ex-situ 1H NMR, IR and XRD.

References

[1] Haiyan Chen, Michel Armand, Jean-Marie Tarascon and Philippe Poizot, J. AM. CHEM. SOC. 31(2009) 8984–8988.

[2] S. Renault, S. Gottis, A.-L. Barrès, M. Courty, O. Chauvet, F. Dolhem, P. Poizot, Energy Environ. Sci. 6 (2013) 2124-2133

Figure 1
Two-Dimensional SiOx As a High Performance Li Storage Material Prepared By Solution Evaporation Induced Interfacial Sol-Gel Reaction
Authors: Yoo Hyundong , Park Eunjun , Bae Juhye , Kim Dae Sik , Lee Jaewoo , Park Min-Sik , Jo Yong Nam , Kim Jung Ho , Dou Shi Xue , Kim Young-Jun , Kim Hansu
Published: February 2020

Si based anode materials for lithium-ion batteries have gained much attention due to its high theoretical capacity (3,580 mAhg-1). However, Si anode materials have critical limit for their commercial use because of their poor cycle performance associated with severe volume changes during cycling. In this work, we synthesized a two-dimensional(2D) SiOx material by solution evaporation induced interfacial sol-gel reaction. This synthesis method is simple, cost-effective and scalable. The resulting 2D SiOx material showed stable cycle performance with reversible capacity of about 650 mAhg-1 even at a high current density of 50 C (50 A g-1). More detailed analysis of two-dimensional SiOx materials will be discussed in this presentation.
New Facile Microwave-Assisted Technique for Chemical Intercalation of Multivalent Cations, Mg2+ and Zn2+, into Cathode Materials for Multivalent-Ion Batteries
Authors: Kaveevivitchai Watchareeya , Manthiram Arumugam
Published: February 2020

Due to a significantly increasing demand for large-scale energy storage units especially for the power grid and sustainable vehicles, systems that are beyond lithium chemistry have gained much attention in recent years. New secondary battery chemistries based on multivalent cation charge carriers, such as Mg2+ and Zn2+, which involve more than one electron transfer, may lead to higher specific capacity and energy density. They are also relatively abundant, inexpensive, and offer superior safety compared to lithium when exposed to air. Despite the advantages of these systems over lithium chemistry, the development of multivalent-ion rechargeable batteries has been hampered by a variety of intrinsic problems related to the design and synthesis of multivalent intercalation cathodes. An approach to developing electrode materials that can reversibly insert multivalent cations is to chemically intercalate ions such as Mg2+ and Zn2+ into a host structure with a highly open framework or large interlayer distance, thus allowing facile multivalent-ion transport. As a result, the inserted Mg2+ or Zn2+cations inside the host structure can serve as charge carriers in energy storage systems.

Traditionally, chemical intercalation is done by using organometallic reagents in heptane or hexane, such as di-n-butylmagnesium for Mg2+ and dimethylzinc or diethylzinc for Zn2+ by constant stirring the solution for 1‒2 weeks. These organometallic compounds are, however, known to be moisture-sensitive and react violently with water, thus raising safety concerns. We present here a new microwave-assisted chemical insertion technique, using the corresponding metal acetate as a metal ion source and diethylene glycol (DEG) as a reducing agent. This approach has been successfully demonstrated in microporous Mo2.5+yVO9+z
host framework with large open channels. Mo2.5+yVO9+z with tunnels constructed by three-, six-, and seven-membered ring units of MO6 octahedra (M = Mo5+/6+ or V4+/5+) belongs to the family of isostructural MoVNbTeO compounds, which are very active oxidation catalysts for light alkanes due to the redox activities of Mo and V. With this microwave-assisted technique, divalent-ion-inserted compounds AxMo2.5+yVO9+z (A = Mg, Zn, 0 < x ≤ 3) can be prepared in as little as 30 min at 160‒200 ºC. The Mg-inserted compounds MgxMo2.5+yVO9+z (0 < x ≤ 3) thus obtained have been investigated as cathode materials in Mg-ion batteries. Our preliminary results suggest that the inserted Mg2+ ions can be removed electrochemically from the framework and reinserted for many cycles.This novel process offers a fast, inexpensive, easily scalable method to insert multivalent metal ions using relatively much safer chemicals which can be carried out in ambient atmosphere.
A Foldable Lithium-Sulfur Battery
Authors: Li Lu , Koratkar Nikhil
Published: February 2020

The next generation of deformable and shape-conformable electronics devices will need to be powered by batteries that are not only flexible but also foldable. Here we report a foldable Lithium-Sulfur (Li-S) rechargeable battery, with the highest areal capacity  (~3 mAh cm-2) reported to date among all types of foldable energy-storage devices. The key to this result lies in the use of fully-foldable and super-elastic carbon nanotube current-collector films and impregnation of the active materials (S and Li) into the current-collectors in a checkerboard pattern, enabling the battery to be folded along two mutually orthogonal directions. The carbon nanotube films also serve as the sulfur entrapment layer in the Li-S battery. The foldable battery showed < 12% loss in specific capacity over 100 continuous folding and unfolding cycles. Such shape-conformable Li-S batteries with significantly greater energy density than traditional lithium-ion batteries could power the flexible and foldable devices of the future including laptops, cell-phones, tablet computers, surgical tools and implantable bio-medical devices.
Understanding Lithium Sulfur Cells, Modelling the Mechanisms behind Voltage- and Capacity-Drop during Discharge
Authors: Offer Gregory James , Zhang Teng , Marinescu Monica , Minton Geraint , Purkayastha Rajlakshmi , O'Neill Laura , Wild Mark
Published: February 2020

The lithium-sulphur (Li-S) cell could provide the next step-change in battery technology with a promising practical energy density of 500-600 Wh/kg. However, a lack of understanding of the complex electrochemical, transport, and phase-change phenomena in Li-S cells is arguably holding back development. Acquiring this knowledge requires experimental characterizations in tandem with mechanistic modelling. In this presentation, we will give an overview of our work on understanding and modelling lithium sulfur cells, and include our latest work on models that capture the essential features of lithium sulfur cell performance. We will also discuss how these models are being used to increase the useable performance of lithium sulfur cells, inform cell design and materials selection, and to create reduced order models for control and system design.

Existing Li-S models do not sufficiently capture the voltage- and capacity-drop mechanisms of Li-S cells during discharge. We first demonstrate that introducing a concentration dependence of the electrolyte conductivity is necessary to retrieve the experimentally documented trends in electrolyte resistance, which contributes to a major voltage-loss mechanism for high-energy density Li-S cells. We further illustrate the existence of an often overlooked potential drop mechanism – the ‘precipitation overpotential’ – which originates from the limited rate of lithium sulphide precipitation. In addition, we propose that the rate capability of high energy-density Li-S cells is mainly limited by the slow transport of ionic species, as is evident from the good agreement between experimental and model-predicted capacity loss at high discharge currents as well as a cell capacity recovery phenomenon that we report for the first time.

References:

Modeling the voltage loss mechanisms in lithium-sulfur cells: the importance of electrolyte resistance and precipitation kinetics, T. Zhang, M. Marinescu, M. Wild, L. O’Neill, and G. J. Offer, Phys. Chem. Chem. Phys. 17, 22581 (2015).

A zero dimensional model of lithium-sulfur batteries during charge and discharge, M. Marinescu, T. Zhang, G. J. Offer, Phys. Chem. Chem. Phys., 2015, advance article.

Lithium Sulfur Batteries, A Mechanistic Review, M. Wild, L. O’Neill, T. Zhang, R. Purkayastha, G. Minton, M. Marinescu and G. J. Offer Energy & Environmental Science, 2015, 8, 3477 - 3494
Vulcanized Polyacrylonitrile with Graphene Oxide As an Additive for High-Rate Rechargeable Lithium Sulfur Batteries
Authors: Li Yang , Zeng Qingcong , Gentle Ian , Wang Da-wei
Published: February 2020

Graphene oxide (GO)-vulcanized polyacrylonitrile (SPAN) composite was developed by mixing additive GO powder with SPAN powder by ultrasound. Its performance was evaluated in Li-S battery with ether-based electrolyte. Surprisingly the pure SPAN cathode is unstable in ether-based solvent compared with in carbonated solvent, unless a certain amount of GO is added. Due to its unique layer-structure, GO could function as the barriers, which could limit the agglomeration of SPAN composite and reduce the dissolution of sulfur accompanying the electrochemical reactions. With the additive of GO, the maximum cathode capacity of 275 mA h g-1 is higher than that of either GO or SPAN alone. This composite cathode possesses high capacity even at high current density of 1.5 A g-1. More importantly, the composite cathode is stable for 500 cycles of discharge/recharge.
Chevron-like Structured SiCu Thin Film Anodes for Lithium Ion Batteries
Authors: Polat Deniz Billur , Keles Ozgul
Published: February 2020

Chevron-like structured SiCu (with 10%at. Cu) thin film is fabricated by ion assisted glancing angle deposition method (IA-GLAD). The possible use of this film as anode material in next generation lithium ion batteries has been evaluated. The galvanostatic test result shows that after 100 cycles, the electrode delivers 900 mAh/g when cycled with 100 mA/g rate. There might have possible reasons for such an improved capacity of the electrode: Cu atoms in the composite film promote electronic conductive pathways in the electrode. Plus Cu atoms might form solid solution phase with Si or generates small sized intermetalics which may enhance the reversibility of the lithiation reaction of the active material (Si in that case) with lithium. Moreover the existence of amorphous and/or nano-sized Si based particles can creates homogenously distributed nano-sized porosities as insterstitial spaces among them.