bluuebunny/crossref_metadata_2025 huggingface dataset:
Advances in Pad Conditioning for Enhancement of CMP Process Stability over Pad Life
Authors: Khanna Aniruddh J. , Jawali Puneet , Redfield Daniel , Kakireddy Raghava , Chockalingam Ashwin , Benvegnu Dominic , Yang Mo , Rozo Sebastian , Fung Jason , Cornejo Mario , Abramson Igor , Yamamura Mayu , Yuan Zhibo , Bajaj Rajeev
Published: February 2020

There is an increasing demand for deposition of thick films because of increasing focus on 3D integration of devices. These thick films will require higher removal rates during the chemical mechanical planarization/polishing (CMP) process in order to avoid significantly high polish times for minimizing impact on throughput of the polisher. Aggressive polishing conditions will be required to achieve high removal rates, which in turn will need aggressive pad conditioning to maintain desired surface texture and prevent glazing of the pad. In this paper, the impact of different pad conditioning sweep profiles on CMP pad thickness profile and removal rate WIWNU & WTWNU will be discussed. A methodology is developed that uses a simulator to predict pad thickness profiles for different pad conditioning sweep profiles. Subsequently, these different pad conditioning sweep profiles are evaluated experimentally to study their impact on pad thickness profiles and material removal rates (MRR) on Applied Materials’ 300mm wafer polisher Reflexion® LK. The pad thickness profiles are characterized by confocal microscopy and state-of-the-art full pad surface metrology tool. Pad thickness profiles predicted by the simulator are compared with those measured using confocal microscopy and full pad metrology tool. It is validated that the pad profile trend predicted by the simulator matches with the actual pad thickness profile obtained on the polisher. Advantage of using full pad metrology tool relative to confocal microscopy is highlighted.
Selective Ion Removal from Water Using Flow-through Electrode Capacitive Deionization
Authors: Cerón Maira R. , Hawks Steven A , Knipe Jennifer M , Loeb Colin K , Zhan Cheng , Pham Tuan Anh , Stadermann Michael , Campbell Patrick G.
Published: February 2020

Capacitive deionization (CDI) is a promising technology that removes ions from solution using charged electrodes and requires less energy than reverse osmosis for removal of salt from low salinity or brackish water. The selective removal of toxic ions from water can be achieved by tailoring the electrode properties such as pore morphology and surface functionality, as well as cell operating parameters, reducing the cost of water treatment. Lawrence Livermore National Laboratory’s unique flow-through electrode CDI platform has demonstrated remarkable selectivity for removal of toxic nitrate in the presence of chloride and sulfate ions, as well as tunable preferential absorbance of monovalent over divalent cations based on pore size. In this talk, we will present our latest results including the development of a multi-scale model (FE + QMD) to help elucidate the mechanism(s) for ion selectivity in CDI.

Fig. 1:
Flow-Through CDI cell

Funding was provided by Lawrence Livermore National Laboratory Directed Research and Development (LDRD) Grant 17-ERD-017. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. IM Release Number LLNL-ABS-763510.

Figure 1
Capacitive Deionization Using Activate Carbon Electrodes Obtained from Different Precursors
Authors: Barcelos Kamilla Malverdi , Zornitta Rafael Linzmeyer , Ruotolo Luis Augusto Martins
Published: February 2020

Capacitive deionization (CDI) is a promising technique for brackish water desalination and water softening. It has been recognized that its performance is strongly dependent of the electrode properties such as specific surface area, pore volume, pore size distribution, and surface functional groups. Carbon is main material that fits all these requirements, allied to its lo high capacitance, conductivity, and low cost. Here, we present a comparison of the different activated carbons (AC) prepared in the Laboratory of Environmental Technologies using sugarcane bagasse fly ash (BFA)1,2, polyaniline activated carbon (PAC)3,4, and lignin activated carbon (LAC)5. Electrodes prepared with these materials were used in symmetric (SY) and asymmetric configurations (ASY)4,5, and in membrane CDI (MCDI)4 as well. The best result was achieved using PAC electrodes prepared applying 500 oC as carbonization temperature. In this case, maximum adsorption capacity was 22.2 mg of NaCl removed per g of electrode, which is among the highest values reported in literature.

References:

Lado et al. (2016) J. Appl. Pyrolysis 120, 389.

Lado et al. (2017) J. Appl. Pyrolysis 126, 143.

Zornitta et al. (2017) Carbon 123, 318.

Zornitta and Ruotolo (2018) Chem. Eng. J. 332, 33.

Zornitta et al. (2018) ChemSusChem 11, 2101.
Electrodeposition of Aluminum Using Chloroaluminate Ionic Liquids Under Dry Air Conditions
Authors: Miyake Masao , Hirata Mizuki , Hirato Tetsuji
Published: February 2020

Electrodeposition of Al at near room temperature using chloroaluminate ionic liquids, represented by the 1-ethyl-3-methylimidazolium chloride−AlCl3 system, has been extensively investigated as a technique for the fabrication of Al coatings. Such coatings have many potential applications, e.g., as corrosion-protective and decorative coatings. The electrodeposition of Al is usually performed under an inert gas atmosphere such as nitrogen and argon in a closed system using a glove box to protect the bath from absorbing moisture. Exposure of chloroaluminate ionic liquids to ambient air readily causes hydrolysis, which makes Al electrodeposition impossible. However, operation in a closed system reduces the productivity and increases the cost of the electrodeposition process, making it unsuitable for a large-scale production in industry.

In this study, the feasibility of the electrodeposition of Al using chloroaluminate ionic liquids under dry air conditions was examined. Such dry air conditions can be maintained in a system that is half-open to ambient air using a dehumidifier. As the electrodeposition process in dry air does not require the use of a glove box, it should be much more productive than in inert atmosphere.

Four kinds of chloroaluminate ionic liquids composed of different organic cations ([cation]Cl−AlCl3) with a molar ratio of [cation]Cl:AlCl3 = 1:2 were employed as the bath for Al electrodeposition. The cations employed were 1-ethyl-3-methylimidazolium, 1-butylpyridinium, 1-butyl-1-methylpyrrolidinium, and trimethylphenylammonium. Electrochemical behavior of Al in these baths in dry air was examined by cyclic voltammetry. Galvanostatic electrodeposition was performed and deposits from these baths in dry air were inspected by X-ray diffraction, scanning electron microscopy, and elemental analysis. The current efficiency was also assessed. These experiments clarified the baths that can produce Al films in dry air with as good quality as the ones obtained in an inert atmosphere. The reactivity between the organic cation and superoxide ion generated by the cathodic reduction of dissolved oxygen seemed to be responsible for the difference in the quality of the Al films electrodeposited from these baths in dry air. The reactions of dissolved oxygen in these baths are discussed.
Conversion of Carbon Dioxide into Valuable Chemicals through Electrochemical Reduction Using Transition Metal Electrocatalysts
Authors: Kassie Birhanu Mulatu , Tsai Meng-Che , Chen Chun-Tse , Woldu Kahsay Amaha , Zeleke Tamene Simachew , Belay Ibrahim Kassa , Huang Chen-Jui , Su Wei-Nien , Hwang Bing-Joe
Published: February 2020

Electrochemical reduction of CO2 is an emerging and current issue for its conversion into valuable product containing high energy density, and simultaneously the reduction helps to reduce the level of CO2 in the atmosphere to maintain within the permissible limit. Among plenty of electro-catalysts copper and gold are efficient and effective catalysts, which are synthesized and applicable for this research work. The metal catalysts (Au and Cu) were prepared in inert environment with different compositions through reduction process from their corresponding precursors. The catalytic performance of CO2 reduction for each composition was performed and resulted good catalytic activity with generation of high current density and relatively small onset potential. The catalytic performance, compositions, morphologies, structure and geometric arrangements were evaluated by electrochemical analysis (LSV, impedance, chronoamperometry & tafel plot), EDS, SEM and XAS respectively. The composite metals showed better selectivity of products (~80% CO) and faradaic efficiencies in addition to the impact of grain size in reduction of CO2. Carbon monoxide, formate, methanol and ethanol are the reduction products, which are detected and quantifiable by chromatographic and spectroscopic techniques considering their physical state of each product.
Modeling the Effect of Layer-on-Layer Cathodes in Lithium-Sulfur Batteries
Authors: Shebert George Leonard , Zhang Rui , Joo Yong Lak , Zamani Somayeh
Published: February 2020

Lithium sulfur (Li-S) batteries are promising candidates for next-generation energy storage due to their high theoretical energy density and environmentally abundant chemical inputs. However, well-known challenges such as polysulfide crossover, large volume changes during cycling, and deposition of insulating lithium sulfide limit the capacity and capacity retention of Li-S batteries. A popular approach to address these issues is to control the structure and properties of the carbon cathode in order to influence the transport of polysulfides, surface area for reaction, and lithium sulfide deposition.

Towards this direction, we developed a layer-on-layer cathode structure with sulfur-impregnated activated carbon alternating with graphene. The layered structure exhibits improved capacity over the control at low rates but the benefits diminish at high rates and high graphene loadings. To explain this behavior, we use a 1-dimension + time numerical continuum model for the Li-S full cell which is validated against experimental data. The model includes the electrochemical reactions and precipitation of sulfur and intermediate polysulfide species, transport of species through the battery, lithium sulfide nucleation and growth, and adsorption of polysulfides. Experiments and simulations suggest that a combination mass-transfer limitations and surface passivation effects is crucial in describing the performance of the cells, and the effect of cathode properties is further investigated using the model.
In-Situ Electrochemical Formation of Na1+XCu3-XO2 for Cathodes in Sodium Ion Batteries.
Authors: Juarez-Yescas Carlos , Ramos-Sánchez Guadalupe , González I
Published: February 2020

In recent years, there has been increasing interest in developing high capacity Na intercalation batteries1-3, mainly because of their similar chemical behavior as Li-ion batteries, low cost of raw materials and abundance of sodium in the earth’s crust. A material of interest for Na-ion batteries is Na2CuO2 with a high theoretical capacity (379 mAh/g and 189 mAh/g, corresponding to 2 and 1 Na ions intercalated). Na2CuO2 has been hypothesized to exist, analogous to the already reported lithium cuprate4 (Li2CuO2); however, it has never been reported. In this work, the NaCuO2 phase is first synthesized through a solid state reaction, with the aim of carrying out further in-situ electrochemical modifications to obtain the Na2CuO2 phase. Preliminary results have shown reversible electrochemical properties of the NaCuO2 phase, upon electrochemical reduction the Na1+xCu3-xO2 (0<x≤1) phase is most likely formed around 1.5 V (vs Na0/Na+ ), Figure 1. A. During galvanostatic cycling, in a voltage window of 1.5-4 V, reversible capacities of 15 mAh/g are achieved, Figure 1. B; however, in a wider potential range (0.7 V to 4.2 V) the first charge cycle reaches capacities of 120 mAh/g, unfortunately fading in subsequent cycles. The capacity fade is partly attributed to the presence of impurities formed during the synthesis of the NaCuO2 phase (primarily CuO and NaOH). Several strategies are carried out to increase the purity of NaCuO2, for instance, improving reactant contact and determining the ideal reaction temperature; on the other hand, further structural characterization is performed to determine the species formed during the reduction of NaCuO2 (e.g. XRD in-situ).

This project has been performed with the financial support from Conacyt PN2016 Project 2551 and SECITI SECITI/080/2017 and C. Juarez-Yescas acknowledges the Postgraduate grant from Conacyt.

Figure 1. A) typical voltammograms (v=0.01 mV/s) and B) charge – discharge curves obtained for 𝑁𝑎0 | 1𝑀 𝑁𝑎𝑃𝐹6 (𝐸𝐶:𝐷𝐶) | 𝑁𝑎𝐶𝑢𝑂2:𝐶𝑆𝑃:𝑃𝑉𝐷𝐹. The charge – discharge curves were obtained at 0.1 C.

References

Vaalma, C., Buchholz, D., Weil, M. & Passerini, S. Nat.
Rev. Mater.
3, (2018).

Kim, H., Kim, H., Ding, Z., Lee, M. H. & Lim, K. Adv. Energy Mater. 1–38 (2016).

Hwang, J.-Y., Myung, S.-T. & Sun, Y.-K. Chem. Soc.
Rev.
46, 3529–3614 (2017).

G. Ramos-Sanchez, I. Romero-Ibarra, J. Vazquez-Arenas, C. Tapia, N. Aguilar-Eseiza, I. Gonzalez,.
Solid State Ionics
303, 89–96 (2017).

Figure 1
Room-Temperature Nonaqueous Polyvalent Metal - Sulfur Batteries
Authors: Yu Xingwen , Manthiram Arumugam
Published: February 2020

Electrochemical energy storage with a room-temperature lithium-sulfur (Li-S) chemistry is gaining overwhelming attention as a promising next-generation rechargeable battery technology for a broad range of applications.1 Beyond Li, sulfur batteries with other anode chemistries, such as sodium, potassium, magnesium, calcium, and aluminum are recently receiving considerable attraction as well.2 In comparison to lithium anode, Ca, Mg, and Al particularly offer multiple advantageous features in terms of safety, materials cost, and abundance. Therefore, rechargeable battery systems with Mg-S, Ca-S, and Al-S chemistries are promising low-cost options for the development of safe, large-scale electrical energy storage technologies. However, the research on these battery chemistries/technologies is still in its infancy and is currently hampered by many critical challenges.

Based on our research into the Li-S, Na-S, K-S, Mg-S, Ca-S, and Al-S batteries,3-8 this presentation will first compare the similarities and differences between the above six battery chemistries. Then, key efforts and significant endeavors toward the success in operating the Mg-S, Ca-S, and Al-S batteries will be particularly presented. Electrolytes play the most important role toward the reversible operation of these polyvalent metal – sulfur batteries. Next, multiple strategies to enhance the cycling performances of Mg-S, Ca-S, and Al-S batteries will be discussed. Specially, advanced cathode matrix materials and unique cathode structures will be detailed in this presentation. Finally, the critical challenges and future research and development directions for developing polyvalent metal – sulfur batteries will be prospected.

References

A. Manthiram, Y. Z. Fu, S. H. Chung, C. X. Zu and Y. S. Su, Chem Rev, 2014, 114, 11751-11787.

X. W. Yu and A. Manthiram, Small Methods, 2017, 1, 1700217.

A. Manthiram and X. W. Yu, Small, 2015, 11, 2108-2114.

X. W. Yu and A. Manthiram, Energy Storage Mater, 2018, 15, 368-373.

X. W. Yu and A. Manthiram, Acs Energy Letters, 2016, 1, 431-437.

X. Yu and A. Manthiram, Chem-Us, 2018, 4, 1200-1202.

X. Y. A. Manthiram, Adv Energy Mater, 2017, 7, 1700561.

X. W. Yu, M. J. Boyer, G. S. Hwang and A. Manthiram, Chem-Us, 2018, 4, 586-598.
Improving the Performance of All-Solid-State Microbatteries By Conformal Electrodeposition of Polymer Electrolyte into Self-Organized TiO2 Nanotubes
Authors: Sugiawati Vinsensia Ade , Vacandio Florence , Djenizian Thierry
Published: February 2020

To date, microbatteries are in demand as small power sources to satisfy the market requirements with fast development of microelectronic devices. As more energy is required, a shift to all-solid-state 3D architectures has been proposed as a promising approach to tackle the challenge and achieve both high energy and power densities [1]. Hence, various types of microbatteries have been developed and are under investigation. It has been reported that self-organized TiO2 nanotubes (TiO2nts) can be utilized as anode material for Li-ion microbatteries [2]. The improved electrochemical performance of TiO2nts electrode has been mainly attributed to the larger surface area offered by 3D nanoarchitectured electrodes which is responsible for high reversible capacity, excellent rate capability and long cycle life [3]. To fabricate an all-solid-state Li-ion microbatteries, conventional liquid electrolytes need to be replaced by the solid electrolytes such as polymer electrolyte. We have reported that the electrodeposition of the polymer electrolyte into TiO2nts electrodes through cyclic voltammetry technique leads to the filling of the nanotubes by the thin polymer film [3].

In this work, we report the influence of the conformal electrodeposition on the full microbattery utilizing TiO2nts as anode, LiFePO4 as cathode and a drop-casted layer of methyl ether methacrylate-polyethylene glycol (MA-PEG) acting as electrolyte and separator. Clearly, the polymer-coated TiO2nts vs. LiFePO4 microbattery reaches higher capacity of ~98 mA h g-1 (~48 μAh cm-2 μm-1) compared to the bare TiO2nts vs. LiFePO4 microbattery (~12.5 mA h g-1 , ~6 μAh cm-2 μm-1) over 100 charge-discharge cycles. Galvanostatic charge-discharge profiles revealed the positive influence of electrochemical deposition of the polymer electrolyte into self-organized TiO2nts, as shown in Figure 1(a) and (b). In this communication, we will discuss the fabrication and characterization of all-solid-state microbatteries, as well as the influence of polymer-coated TiO2nts on their electrochemical performance.

References

[1] S. Ferrari, M. Loveridge, S.D. Beattie, M.Jahn, R.J. Dashwood, R. Bhagat, Latest advances in the manufacturing of 3D rechargeable lithium microbatteries, J. Power Sources. 2015, 28, 25-46.

[2] G.F. Ortiz, I. Hanzu, T. Djenizian, P. Lavela, J.L. Tirado and P. Knauth. Alternative Li-Ion Battery Electrode Based on Self-Organized Titania Nanotubes, Chem. Mater. 2009, 21 (1), pp 63–67.

[3] N. Plylahan, M. Letiche, M.K. Samy Barr, B. Ellis, S. Maria, T.N.T. Phan, E. Bloch, P. Knauth, T. Djenizian, High energy and power density TiO2 nanotube electrodes for single and complete lithium-ion batteries, J. Power Sources. 2015, 273, 1182–1188

[4] N. Plylahan, M. Letiche, M. K. S. Barr, T. Djenizian, All-solid-state lithium-ion batteries based on self-supported titania nanotubes, Electrochem. Commun. 2014, 4, 1388-2481.

Figure 1
The Effect of Metal-Oxide Coating on the Electrochemical Performance of Carbon-Nanofibers Anodes in Lithium-ion Batteries
Authors: Ayala Jonathan , Lopez Jorge , Gonzalez Gabriel , Alcoutlabi Mataz
Published: February 2020

With the invention of the electric cars and the exponential growth in portable electronics over the last decade, energy storage systems that can supply and store more power are of utmost importance. Li-ion batteries (LIBs) entered the market less than a decade ago to keep up with market demands and have since become the most efficient way to store energy due to their reversible nature. Graphite is currently the most widely used material in (LIB) anodes due to its long cycle life and low manufacturing cost, its main drawback being its low theoretical capacity of 372 mAg-1. Metal oxides have been of interest as electrode materials for (LIBs) due to their inherently high theoretical capacities and low cost. However, the main drawback of metal oxide-based anodes includes high volume expansion, particle agglomeration, and dendrite formation. Developments in composites and novel micro/nano-structures that withstand large temperature ranges and maintain structural stability have attracted interest for their use as electrode materials in LIBs. Here, we explore the performance of Iron Oxide (Fe2O3), Tin Oxide (SnO2), Zinc Oxide (ZnO), and Cobalt Oxide (Co3O4), coated on carbon fibers as hosts for lithium ion insertion/de-insertion during charge/discharge process. The synthesis and design of Fe2O3/Carbon and SnO2/C composite fibers were reiliazed by the centrifugal spinning of metal-oxides precursors in polyacrylonitrile (PAN)/ dimethylformamide (DMF) solutions and followed by calcination at 600 °C in an inert gas. The characterization of Fe2O3/C, ZnO/C, Co3O4/C and SnO2/C composite fibers was conducted using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and energy dispersive X-ray analysis (EDAX). The pre-coated carbon fibers with metal-oxide nanoparticle precursors showed improved electrochemical performance compared to the pristine composite carbon-fibers anodes.
A Single Secondary Particle Model for LIFePO4 Electrochemical Performance Evaluation.
Authors: Song Jihun , Park Joonam , Lee Yong Min
Published: February 2020

LiFePO4 (LFP), one of the cathode active materials for lithium ion batteries (LiB), has been adopted as a battery active material in various fields due to its high safety and long cycle life characteristics. However, LFP don’t use widely around the world because of critical weaknesses including low Li+ diffusion coefficient and low electric conductivity. That is the reason currently applied LFP is made as a carbon-coated secondary particle, which can not only secure a lithium migration path within a single particle but also improve the electric conduction property. However, the processes of synthesis of secondary particles highly depends on the manufacturer, and numerous experiments must be needed to synthesize an appropriate particle sizes and even secondary particle sizes. To solve this problem, herein, we built a 3D model using simulation tool using a previously reported literature (Munakata, K Kanamura et al., J. of Power Sources 217 (2012) 444-448). The comparison between experimental data reported in the literature and model prediction to validate the model. Using the model, performance prediction in many cases of particle synthesis in active material are presented.
Structure Engineering and Structure-Property Study of TiNb2O7 Nanofibers As Anode for Safer Lithium Ion Batteries
Authors: Ardoin Sydney , LaCoste Jed , Guo Hui , He Zizhou , Fei Ling
Published: February 2020

Lithium ion batteries (LIBs) have been the dominant energy storage technology for a wide range of applications including portable electronic, electrical vehicles, and grid-scale energy storage. Recently with safety and performance in mind, TiNb2O7 (TNO) has been studied as a promising anode material. It offers a theoretical capacity of 387.6 mA h g-1, which is comparable to that of graphite (372 mA h g-1) and two times that of Li4Ti5O12 (175 mA h g-1). TNO also exhibits an operational voltage larger than 1.0 V (vs Li+/Li0), which helps to avoid formation of dendritic lithium and ensure safe operation. TNO with various morphology and size has been studied intensely since its discovery by Goodenough et. al. in 2011 including mesoporous microspheres, solid or porous nanoparticles, and solid or hollow 1D fibers. However, no comprehensive study which studies the structure-property-aspect of TNO has been completed.

Here, we are trying to prepare TNO with various morphology, size, and porosity as well as to study the correlation of TNO properties with electrochemical performance. Electrospinning technology is used to synthesize target materials, which are formulated from using poly(lactic acid) as a carrier polymer in various solvents (dimethylformamide, acetone, and dichloromethane) and adding titanium and niobium precursors. Parameters that affect the morphology of spun fibers are concentration, flow rate, applied voltage, collector plate distance, viscosity, and surface tension. Those parameters, especially solution chemistry, are carefully tuned to control the resulting fiber morphology and other properties. For example, solid, hollow, and porous (surface porous, inner porous, or highly porous) TNO fibers can be obtained by careful solvent selection as solvents have been proven to strongly affect evaporation and phase separation processes. All prepared TNO are further tested as anode materials in lithium ion battery and the property-performance correlation is carefully analyzed.
Improving Rate Capability and Coulombic Efficiency Via Crosslinking Sulfonated Chitosan Protective Coating on Natural Graphite Anode in Lithium Ion Batteries
Authors: Lu Chia-Yang , Chao Chi-Yang , Wu Nae-Lih
Published: February 2020

Graphite is the mostly used anode material for commercial lithium-ion batteries (LIBs) because of several advantages including low operating potential and low cost. However, the formation of thick solid-electrode interphase (SEI) passivating layer due to solvent and electrolyte decomposition at the graphite surface would be harmful to both Coulombic efficiency (CE) and cell performance at high C-rate. In this work, we successfully develop a multifunctional polymeric artificial SEI (A-SEI) protective layer with thickness in nanometers on active natural graphite (NG) particles in the anode to concurrently promote the rate capability and the CE of the lithium-ion batteries.

The protective layer is composed of crosslinking sulfonated chitosan (X-SCS) containing sulfonated chitosan (SCS) with high degree of sulfonation as main polymer matrix and glutaraldehyde (GA) as the crosslinker. Different ratio of SCS and GA and a variety of curing conditions are applied to optimize the performance. The existence of sulfonic acid groups in X-SCS should allow lithium ions to be feasibly transferred between the electrolytes and the graphite as the pristine X-SCS membrane showed a good ion conductivity > 10-4 S cm-1 at room temperature upon only ~ 20 wt% liquid electrolyte uptake. X-SCS layer should also provide sufficient mechanical strength to protect graphite from exfoliation as a high than 1 GPa Young’s modulus was observed for the pristine X-SCS membrane. The complete coverage of X-SCS on NG was confirmed by testing the battery employing liquid electrolyte (LE) containing 40 wt% PC, which would cause serious exfoliation of NG and lead to unusual high discharge capacity and low CE in the first lithiation process. Normal discharge curves and a much improved CE are observed for X-SCS coated NG in addition to stable cycling performance up to 40 cycles, suggesting the coverage of X-SCS is complete and stable to effectively prevent the direct contact of LE with NG. X-SCS coated NG provided the corresponding half cell an average CE over 99.5% and capacity > 99.5% when operating at 0.3C and room temperature for 100 cycles. In contrary, the average CE for un-coated NG was only 98.7%. Using the charging (de-lithiation) capacity at 0.1 C as reference, an over 98% capacity retention was observed for X-SCS coated NG cell at 5 C while the capacity retention of the bare NG cell was only 90%.
Polycarbonate and Poly(ethylene oxide) Blending As a Solid Polymer Electrolyte for All Solid State Li-Ion Batteries
Authors: Sung Bong-Joon , Didwal Pravin N. , Park Chan-Jin
Published: February 2020

Lithium-ion batteries (LIBs) have been used as a power source for electric vehicles and portable electronic devices. However, conventional LIBs which include organic liquid electrolyte have safety problems such as flammability, leakage of electrolyte, poor thermal stability, and internal short circuit. These safety issues can be addressed using a strategy by switching from organic liquid electrolyte to solid polymer electrolyte (SPE). Among the numerous polymer materials, the poly(ethylene oxide) (PEO) has been extensively studied. Even though PEO possesses some advantages such as high solubility of lithium salt and high ionic conductivity at high temperature, PEO has some drawbacks such as poor mechanical strength, inferior electrical stability window, and poor lithium ion transference number. Recently, polycarbonate which is composed of carbonate group and ethylene oxide, has attracted attentions as polymer electrolyte. This polymer has the higher lithium transfer number and ionic conductivity compared with pristine PEO at room temperature. However, since the strength of polymer was not sufficient for free-standing, the cellulose non-woven was used as framework.

In this work, we studied the effect of blending of polycarbonate and PEO for the use as solid electrolyte. The morphology of blended polymer was investigated by using SEM. The XRD and DSC were used to investigate the crystallinity and glass transition temperature of the blended polymer, and the ionic conductivity of the polymer was investigated. Electrochemical impedance spectroscopy analysis of the polymer showed an increase in ionic conductivity compared with that of pure PEO. In addition, the blended polymer enabled free-standing. The all-solid-state cell composed of Li/polymer/NCM622 was fabricated and its electrochemical performance was evaluated.
Increasing Surface Charge Density By Intrinsic Charge Layer Inclusion for High Performance Efficient Triboelectric Nanogenerators
Authors: Ravichandran Aravind , Ramuz Marc , Blayac Sylvain
Published: February 2020

In recent years, mechanical transducers for energy harvesting, particularly triboelectric nanogenerators (TENGs) have been conceived as a practical power source due to its simple, compact and high efficiency for energy harvesters. Charge injection and retention in thin film dielectric layers remain critical issues in realizing TENGs as a sustainable power source.

In this work, we have presented a novel technique to boost the output electrical performance of triboelectric nanogenerators by the inclusion of charge accumulation layer. This thin film layer allows to store and accumulate the charges generated by triboelectrification and refill the charges on every triboelectrification process of the vertical contact separation TENG mechanism. This increase in the stored charges has an effect of inducing many free charges on the electrodes of the device in a much larger quantity and gives rise to a much higher electrical output power.

A proof of concept TENG structure is devised to validate the electrical output performance. Experimental results show that, the devised structure reaches an open circuit voltage of 600 V demonstrating 25 times enhancement than the conventional triboelectric devices in ambient conditions. The in–situ surface characterization implemented using atomic force microscopy (AFM) reveals the charge retention characteristic due to the presence of the charge accumulation layer.

This technical outcome will significantly facilitate the future research in increasing the charge density to efficiently provide higher output power attractive to charging applications for portable electronics/ wearables and large-scale harvesting without massive volume. By this technique, numerous friction-based operation challenges including lack of uniform contact, material loss through wear, high sensitivity to humidity, and output power storage have been resolved.
Ethylene Carbonate-Free Electrolytes for High-Nickel Layered Oxide Cathodes
Authors: Li Wangda , Dolocan Andrei , Li Jianyu , Xie Qiang , Manthiram Arumugam
Published: February 2020

Layered lithium nickel oxide (LiNiO2), with a specific charge-storage capacity of almost 250 mA h g-1, an operating voltage of 3.8 V vs. Li+/Li, and a high packing density of above 3.4 g cm-3, offers a very high energy density approaching the limits of layered oxide cathode materials for lithium-ion batteries. However, despite early interests in the community, practical application of LiNiO2 was soon dismissed for a multitude of problems. This includes (i) poor thermal-abuse tolerance triggering battery thermal runaway at high states of charge, and (ii) severely restricted reversible capacity of < 200 mA h g-1 for desired cycle/calendar life owing to a high surface reactivity with conventional ethylene carbonate (EC)-based electrolytes and not fully reversible rhombohedral H2/H3 phase transition at > 4.2 V vs. Li+/Li. In spite of recent efforts on stabilizing ultrahigh-nickel layered oxides (Ni > 0.9) during battery operation through compositional tuning, the poor thermal stability and cyclability over a broad Li content range remain challenges of LiNiO2-based cathodes.

Here we design nonaqueous electrolytes with exclusively aprotic acyclic carbonate solvents (such as ethyl methyl carbonate, EMC) tailored to an ultrahigh-nickel layered oxide cathode (LiNi0.94Co0.06O2). Common lithium-conducting salts (e.g., lithium hexafluorophosphate, LiPF6) and interphase-forming additives (e.g., vinylene carbonate, VC) are adopted in two model electrolyte systems. Assembled graphite|LiNi0.94Co0.06O2 pouch-type full cells in the two EC-free electrolyte systems show excellent long-term cycling performance of ~ 80% capacity retention after 1,000 charge-discharge cycles at 25 oC (1C, 2.5 – 4.2 V), notably superior to the same cells in the baseline EC-containing electrolyte (1.0 M LiPF6/EC-EMC(3:7)+2%VC). Through time-of-flight secondary-ion mass spectrometry coupled with lithium isotopic labelling and in situ X-ray diffraction, we demonstrate suppressed unwanted electrode-electrolyte reactions and irreversible structural degradation of LiNi0.94Co0.06O2 at highly delithiated states in the EC-free electrolytes during battery operation. In addition, through differential scanning calorimetry, we also show significantly inhibited self-heating of the ultrahigh-Ni layered oxide cathode at full charge in the EC-free electrolytes, outperforming charged LiNi0.8Co0.15Al0.05O2 in the EC-containing electrolyte. In summary, we present a facile approach of nonaqueous EC-free electrolytes to address the long-standing challenges of LiNiO2-based cathode materials for safer and long-life high-energy-density lithium-ion batteries.
Computational Studies of Organic Sulfides for Energy Storage
Authors: Ma Ying
Published: February 2020

Recently, some organic sulfide materials have been demonstrated to be promising candidates for electrochemical energy storage. Lithium batteries with organic sulfide electrode have shown relatively high capacities while maintaining a good cyclability. It is found that the polysulfide shuttle effect can be greatly suppressed through an on-site trapping mechanism, leading to improved stability. However, theoretical and observed capacities need to be further improved. In this work, first principles computations are used to screen for the optimal organic sulfides. The structures and the associated reaction mechanism upon lithiation are determined computationally. Possibilities to tune the electrochemical performance of these materials through the use of different functional groups are also explored. Computational criteria for evaluating the electrochemical performance of organic sulfides are proposed.
Alleviate Gassing Problem of Li4Ti5O12 Anode Using Polymeric Artificial Solid-Electrolyte-Interphase
Authors: Chang Yu-Hsiu , Wang Fu-Ming , Wu Hung-Chun , Wu Nae-Lih
Published: February 2020

Lithium ion batteries containing lithium titanate (LTO), Li4Ti5O12, as anode material are promising energy storage systems for their safety and long cycle-life. However, there is a critical problem of extensive evolution of gases during cycling or storage of LTO cells, which results in capacity fading and poor cycling performance. This is particularly a major issue when the water-based binder is intended to be used for the LTO anode. In this study, we successfully developed an artificial solid-electrolyte-interphase (ASEI) coating that, when coated onto the LTO electrode, substantially alleviate the gassing problem of the electrode. The gassing behaviours of the LTO electrodes, either with or without the ASEI, have been characterized using operando gas chromatography/mass spectrometry (GCMS) analyses. It is furthermore demonstrated that the ASEI enables the LTO electrode to be compatible with water-based binder, such as alginate.

Figure 1
Redox Chemistry in Conventional Layered Lithium Metal Oxide Cathodes
Authors: Tong Wei , Li Ning , Yang Wanli , Sallis Shawn , McCloskey Bryan D. , Papp Joseph K
Published: February 2020

Li-ion battery technology is one of the best performing energy storage devices and holds the best promise to power the upcoming electrical vehicles (EV). Extensive efforts have been devoted to further advancing conventional layered oxide cathodes, such as LiNixMnyCozO2 and LiNixCoyAlzO2 (0 < x, y, z <1), for Li-ion batteries of even better performance and lower cost ($/Wh). Strategies that are largely pursued include increasing Ni content to achieve a higher practical capacity at a given charge cutoff voltage and/or increasing charge cutoff voltage for a given composition. Alongside with these research efforts, questions regarding the stability of electrode, especially at highly delithiated states, electrolyte and electrode/electrolyte interface arise.

In this work, of particular interest is the redox chemistry upon electrochemical (de)lithiation of LiNiO2, the parent compound of Ni-rich layered oxides, with a key focus on highly delithiated states in the high voltage region. Electrochemistry of LiNiO2 seems straightforward, in principle, Ni3+/Ni4+ redox can perfectly accommodate 1 Li+ transport during (de)lithiation process. However, the precise state at full oxidation of Ni3+ to Ni4+ and/or full removal of 1 Li+ are difficult to achieve because of the possible side reactions between highly charged electrode and electrolyte, for example, surface Ni reduction and gas evolution upon charge often occur at high voltages. Here, the electronic states of Ni and O are probed at different states of charge through combined soft X-ray absorption (XAS), resonant inelastic X-ray spectroscopy (RIXS) and in situ differential electrochemical mass spectrometry (DEMS) in the high voltage region to elucidate the explicit redox chemistry in LiNiO2. This work is anticipated to provide additional insights into the redox chemistry of conventional Ni-rich layered oxides, especially its utilization in the high voltage region.
Dandelion-like Mesoporous SiOx@C Nanoparticles for High-Capacity and Ultralong Lifespan Lithium-Ion Battery Anode
Authors: Li Zhaolin , Zhao Hailei , Wang Jie
Published: February 2020

Silicon suboxide (SiOx, 0˂x˂2) is one of the promising anode materials for lithium-ion batteries (LIBs) due to its high specific capacity, low operating voltage (˂0.4 V) and rich natural resource [1]. SiOx converts to Si nanoparticles and inert components (lithium oxide and lithium silicate) during initial lithiation process, where the Si nanoparticles can reversibly store lithium ions and the inert components act as buffer matrix to accommodate the large volume variation of nano-sized Si. Compared to pure Si, SiOx electrode shows relatively good cycling stability while maintaining high specific capacity, thus is a promising anode material for high energy density Li-ion batteries. Nevertheless, bulk SiOx electrode cannot withstand long-term cycling due to the inevitable volume variation upon lithium uptake and removal. In addition, the poor intrinsic electrical conductivity of SiOx often limits the capacity utilization [2].

In this work, we prepared mesoporous SiOx@C nanoparticles with unique “dandelion flower” structure by a facile microemulsion method combined with a subsequent carbon coating process. The SiOx particles display a dandelion flower like porous structure with large void space and specific surface area. A uniform carbon layer wholly encapsulates the SiOx backbone, forming a 3D mono-dispersed SiOx@C particle with particle size of ~70 nm. The abundant mesopores inside particle can accommodate the volume expansion of SiOx during lithiation and lower the diffusion-induced stresses, which prevent from the electrode pulverization and thus maintain the structural integrity of SiOx@C electrode during repeated cycles. The 3D carbon network not only effectively facilitates the fast electron transport throughout the whole SiOx particle and thereby improving the electrode reaction kinetics, but also homogenizes the local current density of active particles and hence decreases the mechanical stress induced by volume change of SiOx. Benefiting from these advantages, the prepared SiOx@C anode exhibits ultrahigh reversible capacity (1261 mAh g-1 at 0.1 A g-1), ultralong lifespan (635 mAh g-1 at 2 A g-1 after 1000 cycles with retention of 88.6%), as well as superior rate capability (293 mAh g-1 at 10 A g-1).

[1] Journal of Power Sources, 2017, 363: 126-144.

[2] J. Mater. Chem. A, 2014, 2, 3521-3527.
Facile Technique for the Production of Metal Oxide Anodes for Lithium Ion Batteries
Authors: İnel Eren , Karahan Billur Deniz , Keles Ozgul
Published: February 2020

Ferrotitanium is a ferroalloy that primarily consists of iron and titanium along with aluminum and manganese etc. In this study, sulphuric acid leaching is applied to fabricate metal oxides containing trace of other elements. The effects of temperature and leaching duration on the yield and the morphology of oxides have been investigated. The resulting powders’ surface morphologies are analyzed by secondary electron microscope, and their structures are characterized based on X-ray Diffraction method. The possible use of the resulting metal oxides as anode materials for lithium ion batteries has been discussed based on electrochemical test results.
Development of Carbon Fiber-Based Electrodes for Lithium-Ion Battery
Authors: Liu Yi-Hung , Lin Heng-Han , Hsu Chun-Han
Published: February 2020

Introduction

To meet the increasing requirement on high energy density, power density and long cycle life of large-scale lithium ion batteries (LIBs), advanced electrodes which can afford more active material loading while reducing extra use of additives are desired. In light of this purpose, carbon fibers (CFs) are regarded as a potential material because they can be used as current collectors where more active materials can be loaded on their 3-dimensional (3D) electrically conductive network. In addition, CF-based current collectors enable a binder-free electrode design for lithium ion batteries and sodium ion batteries (SIBs). [1,2] In this work, we develop several CF-based electrodes for use in not only positive electrode but negative electrode of LIBs, demonstrating their characteristics in terms of electrode fabrication methods and electrode performances.

Experimental

For the fabrication of CF-based electrodes, two approaches, namely hydrothermal and sol-gel reaction routes, are applied. In the hydrothermal process, an electrodeposition of precursor was first carried out, followed by the hydrothermal reaction and post-calcination treatment to synthesize the target active material. For the sol-gel route, active materials were primarily synthesized in the sol-gel reaction step. After a calcination treatment of the gel, powder-type active materials can be obtained. Then, a slurry was prepared by mixing the powders with solvents and specific additives. After coating the slurry on CFs and drying, fabrication the CF-based electrodes were completed. SEM and XRD are generally used for the material analysis. With respect to the electrochemical evaluation, a coin cell (CR2032) was used to accommodate the CF-based working electrode and lithium metal foil as a counter/reference electrode.

Results and Discussion

According to the electrode performances, it is convinced that both hydrothermal and sol-gel routes are appropriate for the fabrication of CF-based electrodes. The physical properties, including morphology, chemical composition and crystallinity, vary depending on the fabrication methods and conditions. While the hydrothermal route is capable of binder-free electrode design, the sol-gel route offer the benefit to the formation of active materials with purer crystal phase and better crystallinity. Moreover, CF-based electrodes exhibit satisfactory electrode performances due to their 3D conductive structure, facilitating ion transport and electron conduction during the cell operation.

References

1. Y. H. Liu, H. H. Lin, Y. J. Tai, J. Alloy. Compd., 735, 580–587 (2018).

2. Y. H. Liu, T. Takasaki, K. Nishimura, S. Katsura, M. Yanagida, and T. Sakai, J. Electrochem. Soc., 161, A1194–A1199 (2014).
Achieving High Capacity at High Rates in Aqueous-Based Zn-Ion Batteries Via Advanced 3D Electrode Design and Mixed-Salt Electrolytes
Authors: Sassin Megan B. , Ko Jesse S. , Donakowski Martin D. , Parker Joseph F. , Long Jeffrey W. , Rolison Debra R.
Published: February 2020

Manganese oxides (MnOx) are a well- established class of active materials for electrochemical energy- storage technologies ranging from primary alkaline to rechargeable Li- ion batteries and more recently, have shown great promise in electrochemical capacitors. The widespan applicability of MnOx in these different devices stems from the use of different electrode structures and electrolyte compositions. However, we have demonstrated that with the use of an advanced 3D electrode architecture in which the MnOx component exists as a conformal nanoscale coating on a carbon nanofoam paper with a through-connected pore structure, it is possible to deliver full theoretical capacity of LiMn2O4, a nominal battery material, at EC-like rates in an aqueous electrolyte. We are now extending the performance enhancements gained via the 3D electrode architecture demonstrated for Li-ion battery chemistries to aqueous-based Zn-ion batteries comprised of a MnOx@carbon nanofoam cathode and a Zn anode. We show that the MnOx@carbon nanofoam delivers full theoretical capacity (308 mA h g-1) at 1 C when cycled in an aqueous mixed salt electrolyte (e.g., 0.75 M Na2SO4 + 0.25 M ZnSO4) – delivering high capacity at high rate in a single electrode. To gain a better understanding of the charge-storage reactions occurring in this complex system, we perform a suite of characterization methods as a function of potential. Electrochemical impedance spectroscopy confirms that MnOx stores charge via pseudocapacitance, supported by the presence of Na ions in the electrolyte, at potentials not associated with Zn2+ insertion/extraction. Ex-situ surface characterization of discharged MnOx@carbon nanofoam electrodes reveal the formation of Zn4(OH)6SO4·5H2O crystallites on the exterior surface, but no evidence of those precipitates after recharge. The ability to deposit/dissolve the Zn4(OH)6SO4·5H2O precipitates in conjunction with pseudocapacitive charge-storage supports long-term cycling ability, with minimal decrease in capacity over 1000 cycles.