bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Hybrid Supercapacitors: Their Evolution to Second and Third Generations
Authors: Naoi Katsuhiko , Naoi Wako 
Published: February 2020

To meet growing demands for electric automotive and regenerative energy storage applications, researchers all over the world have sought to increase the energy density of electrochemical capacitors. Hybridizing battery capacitor electrodes can overcome the energy density limitation of the conventional electrochemical capacitors because they employ both the system of a battery-like (redox) and a capacitor-like (double-layer) electrode, producing a larger working voltage and capacitance. However, to balance such asymmetric systems, the rates for the redox portion must be substantially increased to the levels of double-layer process, which presents a significant challenge. An in situ material processing technology called “ultracentrifugation (UC)” has been used to prepare a novel ultrafast Li4Ti5O12 (LTO) nanocrystal electrode for capacitive energy storage.
The present paper describes an extremely high-performance supercapacitor that utilizes highly optimized “nano-nano-LTO/carbon composites” prepared via the UC treatment. The UC-treated LTO nanocrystals are grown as either nanosheets or nanoparticles, and both have hyperlinks to two types of nanocarbons: carbon nanofibers and supergrowth (single-walled) carbon nanotubes. Using this ultrafast material, we assembled a hybrid device called a “nanohybrid capacitor” that consists of a Li-intercalating LTO electrode and a non-Faradaic AC electrode employing an anion adsorption desorption process. The “nanohybrid capacitor” cell has demonstrated remarkable energy, power, and cycleability performance as an electrochemical capacitor electrode.
The new-generation “nanohybrid capacitor” technology produced more than triple the energy density of a conventional electrochemical capacitor. Moreover, the synthetic simplicity of the high-performance nanostructures makes it possible to scale them up for large-volume material production and further applications in many other electrochemical energy storage devices.
References
[1] K. Naoi, Fuel Cells, 10, 825 (2010), [2] K. Hata, D.N. Futaba, K. Mizuno, T. Namai, M. Yumura, S. Iijima, Science, 306, 1362 (2004), [3] K. Naoi, S. Ishimoto, J. Miyamoto, W. Naoi, Energy & Environmental Science, 5, 9363 (2012), [4] K. Naoi, W. Naoi, S. Aoyagi, J. Miyamoto, T. Kamino, Accounts Chemical Research, 46,1075(2013).
Aqueous-Based Polymer Electrolytes for Solid Energy Storage Systems
Authors: Lian Keryn , Li Jak , Virya Alvin , Foong Yee Wei , Wu Haoran , Gao Han 
Published: February 2020

The rapid growth in printable and wearable electronics has significantly increased the demand for high performance thin, flexible, and light-weight power sources. Solid-state energy storage devices, batteries and supercapacitors, enabled by polymer electrolytes are ideal solutions for such applications. In order to facilitate and promote high throughput and low cost (materials and processes) solid energy storage devices for wearable electronics, the polymer electrolytes should be highly conductive, easy to process, and possess good chemical and environmental stability in ambient conditions.
We have developed a series of aqueous-based polymer electrolytes that are proton-conducting, hydroxide ion-conducting or neutral salt ion-conducting to match various cell chemistries. These aqueous-based polymer electrolytes can be applied via casting or printing methods and can potentially be implemented in roll-to-roll operations. One example is the polyacrylamide (PAM) system, in which ionic conducting species together with additives were blended into aqueous polymer matrix. In this work, three ionic conducting systems based on silicotungstic acid (SiWA) as proton-conductor [1], tetraethylammonium hydroxide (TEAOH) as anion conductor [2] and LiCl as neutral ion conductor were investigated. These three electrolytes all exhibited ionic conductivities > 10-2mS/cm and maintained stable performance under ambient conditions (room temperature and 45% relative humidity). Figure 1 shows a comparison of these 3 polymer electrolytes in terms of their ionic conductivity as a function of storage time. In this talk, an overview of these three polymer electrolytes will be provided. Materials and electrochemical characterizations of the polymer electrolytes as well as their performance in electrochemical double layer capacitors will be discussed and compared.
References:
[1] H. Gao and K. Lian, "Proton-Conducting Polymer Electrolytes and Their Applications in Solid Supercapacitors: A Review", RSC Advances, 2014, 4, 33091-33113.
[2] H. Gao, J. Li, and K. Lian, "Alkaline Quaternary Ammonium Hydroxides and their Polymer Electrolytes for Electrochemical Capacitors", RSC Advances, 2014, 4, 21332-21339.

Figure 1
Electrochemical Characteristics of Graphite Felt Electrode By Surface Modification for Vrfbs
Authors: Noh Tae-Hyoung , Kim Min-Young , Lee Moo-Sung , Park Hong-Sik , Kim Ho-Sung 
Published: February 2020

Recently, there has been a lot of research in vanadium redox flow battery (VRFB) which is used as a large scale energy storage system and power supplier. Especially, graphite electrodes play an important role because they do directly act as electrochemical reaction in cell. In this study, commercial graphite felts were prepared by heat treatment in the range of 400 to 600 °C, controlling the condition of heat treatment such as air purity, heating processing time. As a result, the surface morphology and oxide of electrode were observed by SEM and XPS. Moreover, electrochemical evaluations such as CV (Cyclic Voltammetry) and impedance were performed in three electrode cell at room temperature, in which the kinetic properties of electrode were different with the condition of surface modification. Furthermore, small VRFB full cells constructed with the graphite felt showed the properties of charge and discharge profile corresponding to the above analysis and electrochemical test. Therefore, we will introduce the effect of heat treatment on the graphite felt electrode and its correlation in electrochemical reaction in more detail.
The Role of Lithium Superoxide in Li-O2 Batteries
Authors: Curtiss Larry 
Published: February 2020

There has been much interest in rechargeable aprotic lithium-oxygen (Li-O2) batteries because their energy density can be significantly higher than that of the conventional Li-ion batteries. However, many challenges remain for Li-O2 batteries before they can become a reality. Understanding the growth and nucleation mechanisms of the discharge product is one of the keys to addressing these challenges because it controls the resulting morphology and composition of the discharge product. The efficiency and reversibility are dependent on the type of morphology and composition that is formed during discharge. In this paper experimental and computational results will be reported that have shed light on the growth and nucleation mechanism in Li-O2 batteries. Specifically, the role of lithium superoxide (LiO2) in the nucleation and growth mechanism during discharge and how to suppress the disproportionation reaction of LiO2 to lithium peroxide (Li2O2) will be discussed. The implications of these new results for reducing charge overpotentials in Li-O2 batteries and in the design of new cathode materials will be discussed.
Making the Invisible Visible - Advanced Diagnosis Methods for Lithium Ion Rechargeable Battery Materials
Authors: Meng Ying Shirley 
Published: February 2020

Scanning electron microscopy and electron energy loss spectroscopy (STEM/EELS) offers unprecedented spatial resolution, which has enabled nanoscale imaging and chemical analysis of battery materials - their surfaces, grain boundaries and phase boundaries. Combining the state-of-the-art in situ operando analytical electron microscopy with first principles (FP) computational data analysis, we reveal some insights that could not be possible to see in the past. On the other hand coherent x-ray diffractive imaging (CXDI), a lensless form of microscopy capable of discerning electron density and strain with 20 nm resolution, can be used to map the strain evolution of a single cathode particle in a functional battery material as it is cycled in-situ. The evolution of compressive/tensile strain reveals a number of interesting phenomena. For instance, strain can be quantitatively correlated to the Lithium amount in the initial cycles, eventually becoming uncorrelated upon long-term cycling. We demonstrate that CXDI is a powerful diagnostic tool to reveal correlation between strain and electrochemistry at the single particle level and offers valuable information for electrode/battery modeling and future battery design. By combining electron based and X-ray based novel imaging techniques, we showcase the state-of-the-art diagnostic tools developed for probing functional battery materials in operando.
Electrolytes for Li-Ion Batteries: Limitations, Challenges and Opportunities
Authors: Cekic-Laskovic Isidora , Nowak Sascha , Schappacher Falko , Winter Martin 
Published: February 2020

Although lithium ion batteries are considered as system of choice for variety of mobile and stationary applications, fundamental knowledge is alarmingly required to uncover the underlying principles controlling the basic processes that determine and dictate their function, operation, performance limitations as well as failure. In this underpinning way, considerable improvements and new concepts in respect to the stable electrode active materials and electrolyte formulations can be achieved leading to electrochemical systems with long life, high energy density, high power and adequate safety at a competitive manufacturing cost. Due to the complexity of electrolyte formulation, determined by the physicochemical properties of its components, namely inorganic fluorinated salts, organic solvents and additives, the desired operation performance is always accompanied by inevitable side reactions. Recent advances in selected ex situ, online and in situ techniques, combined with theoretical approach, outline and provide deeper insight into the dynamic, complex and not well-understood cell chemistry. In this mechanistic game, victory is assured to those who are best able to piece together conclusions obtained from synthetic, structural, kinetic, spectroscopic as well as electrochemical studies and construct the mechanism capable of explaining the results. Thorough investigation and elucidation of those fundamental, mechanisms including chemical, physical, electrochemical and interfacial processes guide and strengthen the further advancement of the existing state of the art Li ion batteries and stimulate development of the next generation rechargeable batteries.
Since an electrolyte has a complex starting composition, analytical and electrochemical techniques have to be developed and applied for the numerous individual species that are present in the system. By means of developed analysis methods, decomposition products can be evaluated to determine operation and failure mechanisms as depicted in Figure 1.

Figure 1
Operando Diffraction During Li Battery Operation Using Neutron and Synchrotron X-Ray Radiations
Authors: Masquelier Christian , Bianchini Matteo , Suard Emmanuelle , Fauth François , Croguennec Laurence 
Published: February 2020

Performing in situ and operando measurements on electrode materials for Li-ion and Na-ion batteries is of importance for their understanding and improvement. Electrode materials need to be studied in their environment (in situ) and in real time while they function (operando), since they normally operate in non-equilibrium conditions. Real-time experiments upon charge/discharge of the electrodes (i.e. upon lithium or sodium extraction/insertion from/into the electrodes) unveil dynamics that are not accessible by other means and allow a more complete understanding of the electrodes’ functioning. The use of different probes is an important requirement for the study of such reactions. The combined use of X-Ray Powder Diffraction (XRPD), Synchrotron radiation XRPD and Neutrons Powder Diffraction (NPD) allows observing any atomic element in any crystalline electrode. However, custom setups are required to carry out operandodiffraction experiments on batteries.
We will address the development of a sample environment suitable for both electrochemistry and neutron powder diffraction using an electrochemical cell featuring a (Ti,Zr) alloy and a deuterated version of the electrolyte [1]. The cell is able to function using massive electrodes (massive on the battery scale, but a small sample for neutrons) with good performances and able to give NPD patterns of high quality for data analysis. Importantly, we showed the possibility to succeed in reliable structural refinements (by the Rietveld method) and thus to observe structural modifications in details, from unit cell parameters to atomic coordinates and even site occupancy factors. We will discuss a few studies done with this setup, namely the observation of lithium extraction from different samples in the family of spinels Li1+xMn2-xO4. We performed NPD in real time on three samples (LiMn2O4, Li1.05Mn1.95O4 and Li1.10Mn1.90O4) and showed how the Li/Mn ratio influences the phase diagram of the material [2]. New insights obtained from high resolution – high flux Synchrotron X-Ray diffraction data will be presented, in particular the existence of a Li+ and Mn3+/Mn4+ ordering within the spinel-delithiated composition Li0.5Mn2O4[3].

Acknowledgements

This research is performed in the frame of the French network RS2E (http://www.energie-rs2e.com) and of the European network ALISTORE-ERI (http://www.alistore.eu).

References

[1] Bianchini et al., J. Electrochem. Soc., 160(11), A2176-A2183 (2013)
[2] Bianchini et al., J. Phys. Chem. C, 118(45), 25947-25955 (2014)
[3] Bianchini et al., Acta Cryst., B71, 688-701 (2015)
New Polyimides As Electrode Materials for Li-Ion Batteries
Authors: Hernández Guiomar , Morozova Sofia M. , Shaplov Alexander S. , Lozinskaya Elena I. , Vygodskii Yakov S. , Shanmukaraj Devaraj , Armand Michel , Mecerreyes David 
Published: February 2020

Currently, Li-ion batteries are based on inorganic oxides as cathodes, although they fail in terms of safety and sustainability. Recently redox-active polymers have attracted considerable attention as an alternative to inorganic cathode materials due to their low solubility in common electrolytes, film forming ability, excellent thermal stability and tunable redox properties. Among redox polymers, polyimides (PIs) are known for their ability to undergo reversible electrochemical reduction/oxidation as well as for offering high capacities.
To extensively explore the influence of chemical structure on the electrochemical properties of polymers a series of PIs based on three aromatic dianhydrides and various diamines incorporating ether segments, ionic fragments and additional lactone cycle were synthesized (Fig. 1). The expected improvement in the performance of the cells based on ionic PIs through the additional solvation of Li+ by ionic fragments was not reached feasibly because of the electrostatic repulsion effect. In contrast, the insertion of short ether moieties in PI’s backbone allows for the desired Li+ solvation, increase of their mobility and rise in the batteries capacity. Among synthesized series, PIs derived from 1,4,5,8-naphthalene tetracarboxylic acid dianhydride and 4,7,10-trioxa-1,13-tridecanediamine showed best battery performance: excellent charge/discharge efficiency, high specific capacity (up to 140 mAh g-1) and the capability to reversibly operate at relatively high rates (up to C/5).
This work was supported by the Russian Foundation for Basic Research (projects no. 14-29-04039_ofi_m and 16-03-00768_a) and by European Commission (project no. 318873 «IONRUN»). Electrochemical experiments were run at CIC Energigune through a collaboration with Polymat.

Figure 1
Li2MnO3/Graphene Composite Anode Material for Lithium Ion Battery
Authors: Luo Hongze , Wen Lei 
Published: February 2020

Lithium ion batteries have been popularly used as the rechargeable power sources in consumer electronics due to their high energy storage density since the first commercial lithium ion battery launched by Sony in 1991. Graphite is still commonly used as anode material for commercial Lithium ion batteries due to its low redox potential close to Li+/Li, good cycling stability, low cost, and environmental friendliness.[1] However, the performance of current lithium ion batteries, which use graphite as the anode material, cannot satisfy requirements of fast charge Lithium ion batteries. The volume expansion/contraction of the graphite associated with the lithium insertion and extraction process, which results in loss of inter-particle electronic contract, consequently, lead to poor cycling stability. Another consideration of graphite is their safety caused from lithium dendrite formation due to its low Lithium intercalation potential at about 0 V (vs. Li/Li+). [2]
The search for new anode materials for lithium ion batteries has been an important way to satisfy the ever-growing demands for better performance with higher energy/power densities, improved safety and longer cycle life. Recently, Li2MnO3
was investigated as an anode material for lithium ion battery.[3] Li2MnO3 exhibits much higher capacity than conventional carbon-based materials and a very stable cycling performance.
In this work, as-prepared Li2MnO3/graphene composite material shows the enhanced reversible specific capacity and the rate performance compared with that of pristine Li2MnO3
. It was found that the conductivity of Li2MnO3/graphene was significantly improved by forming a conductive graphene network throughout the insulating Li2MnO3.
References
1. Peled, E., D. Golodnitsky, and G. Ardel, Advanced model for solid electrolyte interphase electrodes in liquid and polymer electrolytes. Journal of the Electrochemical Society, 1997. 144(8): p. L208-L210.
2. Zheng, G.Y., et al., Interconnected hollow carbon nanospheres for stable lithium metal anodes. Nature Nanotechnology, 2014. 9(8): p. 618-623.
3. Wang, D.D., et al., Novel Li2MnO3 nanowire anode with internal Li-enrichment for use in a Li-ion battery. Nanoscale, 2014. 6(14): p. 8124-8129.
Towards Following SEI Formation in-Situ Using Ambient Pressure Photoelectron Spectroscopy
Authors: Maibach Julia , Maripuu Rein , Andersson Margit , Urpelainen Samuli , Schnadt Joachim , Gustafsson Torbjörn , Rensmo Hakan , Edstrom Kristina , Siegbahn Hans , Hahlin Maria 
Published: February 2020

Despite the large number of studies targeting surfaces, (buried) interfaces and chemical gradients in battery electrodes, the processes leading to the formation of the solid electrolyte interphase (SEI) are not yet fully understood. Fundamental research on the SEI’s formation process is necessary for controlled design of chemistries that lead to long term stable and functional solid/liquid interfaces in Li-ion batteries. Many of the components suggested to form within the SEI are highly reactive, and may directly upon formation further react with the surrounding components. Since most studies are performed post-mortem meaning after the battery has been taken apart, a missing key point is the study of the SEI formation process in real time. Ambient pressure photoelectron spectroscopy (AP-PES) offers the possibility to obtain more realistic information about the formation of these sensitive interfaces as experiments can be conducted at elevated pressures and with liquids present.
We will present results from our recent advances within the field of characterizing battery materials using AP-PES. This includes a new AP-PES instrumentation developed in Uppsala [1] together with a novel methodology for the direct investigation of the interface between the solid electrode and liquid electrolyte [2]. The latter technique was demonstrated with a Li-ion battery and for the first time enabled the study of the SEI in the Si|LiClO4in PC|Li battery system with the electrolyte present. The results show that the SEI composition for the wet electrode is stable within the probing time and generally agrees well with traditional UHV studies.
Using advanced near ambient pressure cell design at the SPECIES beamline at MAX-lab [3], we have studied Li metal in presence of PC vapor and for the first time in contact to a droplet of liquid PC (see Figure 1). The results from these studies concerning PC adsorption, stability during measurement conditions and radiation exposure are the basis for further electrolyte characterizations and the development of an in-situ electrochemistry cell, which will enable battery electrode cycling directly in the AP-PES setup.

References

[1] S. K. Ericsson et al., Rev. Sci. Inst. 85 (2014), 075111/1
[2] J. Maibach et al., Rev. Sci. Inst. 86 (2015), 044101
[3] J. Schnadt et al., J. Synchrotron Rad. 19 (2012), 701-704

Figure 1
Mechanism of Capacity Fading of Li-Rich Layer-Structured Cathode Materials Based on TEM/Electrochemical Analyses
Authors: Fung Kuan-Zong , Tsai Shu-Yi , Ni Chung-Ta , Huang Bo-Yuan 
Published: February 2020

Recently, Li-rich layer-structured cathode formulated as xLi2MnO3 -(1-x)LiMO2(M = Mn, Ni, Co, etc.) exhibit high reversible capacity for Li-ion battery applications. Although Li-rich layer-structured cathode material show a reversible capacity as high as 250 mAh/g, its electrochemical properties such as capacity loss at first cycle, rate capability and capacity fading upon cycling still need to be investigated. A systematic study on crystal structures and electrochemical testing is employed.
In this study, various compositions of xLi2MnO3 -(1-x)LiMO2 (M = Mn, Ni, Co, etc.) were investigated. The electron diffraction pattern of spinel structure was observed from a cycled layer-structured cathode particle. The transition from layered structure to spinel structure may induce a large lattice distortion resulting in lattice breakdown and capacity. Furthermore, the phase transition may be caused by the redox reaction of transition metal ions through repeated cycling tests. Discussion will be carried out based on the results of XRD, SEM, TEM analyses on cycled cathode materials