bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examining the Electrochemical Impedance at Low States of Charge in Lithium- and Manganese-Rich Layered Transition-Metal Oxide Electrodes
Authors: Gallagher Kevin G. , Gowda Sanketh R. , Jansen Andrew N. , Dees Dennis W. 
Published: February 2020

Lithium- and manganese-rich layered transition-metal oxide (LMR-NMC) intercalation electrodes are projected to enable batteries with high energy density and low costs for energy. However, implementation of LMR-NMC materials are challenged by life limiting mechanisms as well as less than desired rate performance. Here-in, we use electrochemical characterization of LMR-NMC electrodes to examine the large magnitude of impedance and the asymmetric polarization between charge and discharge at low states of charge (SOC).
The lithium metal oxide cathode materials examined were LMR-NMC and standard NMC both from Toda Kogyo (Japan). The LMR-NMC material, referred to as HE5050, had the composition 0.5Li2MnO3•0.5LiMn0.375Ni0.375Co0.25O2 (or in layered notation Li1.2Ni0.15Mn0.55Co0.10O2). The NMC material had composition of Li1+x(Ni1/3Mn1/3Co1/3)1-xO2 and can be considered to be the commercial standard stoichiometry for Li-ion transportation cells at the time of this publication. Full cells used A12 graphite (Conoco Phillips) and half cells used lithium metal (FMC Lithium) both with standard LiPF6based carbonate electrolyte. A three electrode pouch cell was utilized for the asymmetry polarization experiments in the study, with a composite LMR-NMC electrode as the working electrode, lithium metal was used as the reference and counter electrodes
The area-specific impedance (ASI) of LMR-NMC in Fig. 1 displays a similar dependency as standard layered lithium metal oxides when compared as a function of voltage rather than SOC. The increasing and asymmetric behavior of the polarization in LMR-NMC measured at low SOC is hypothesized to be the result of the differing lithium contents and lithium mobilities in the heterogeneous, nano-composite metal oxide material. Transport of lithium within LMR-NMC is suggested to be governed by the relatively facile nickel- and cobalt-rich domains even as this domain appears to reach full lithiation. As the majority of capacity at low SOC in LMR-NMC is associated with the lithium- and manganese-rich domains, the observed high impedance presents a significant hurdle to utilizing this capacity in moderate power-to-energy ratio applications. Much work is needed to clarify the transport and structural mechanism in LMR-NMC. Other studies have shown the structural transformation known as voltage fade is less severe with lower lithium content. However, lowering the lithium stoichiometry also tends to lower the specific energy of the material at beginning of life. Optimizing the stoichiometry of the lithium and manganese to achieve a maximum specific energy over life at relevant discharge rates is a potentially viable path forward.

Figure 1
High-Performance Non-Aqueous Redox Flow Batteries at Pnnl
Authors: Wei Xiaoliang , Xu Wu , Cosimbescu Lelia , Vijayakumar Murugesan , Liu Tianbiao , Liu Jun , Wang Wei , Sprenkle Vincent 
Published: February 2020

With the potential applications in power grid stabilization, redox flow battery has been widely considered as a promising large- and middle-scale stationary energy storage technology. The cell architecture enables separation of the energy capacity and power rating, offering excellent scalability and tremendous design flexibility to meeting different energy-to-power ratio requirements. Traditional aqueous flow batteries have been extensively developed, but the limited voltage window narrows down the intrinsic capacity to achieve high energy density. Therefore, alternative nonaqueous redox flow techniques are rapidly emerging because of their wider voltage window that has a direct impact on the energy density. Currently, the primary focus of the nonaqueous flow research is on the flow chemistry study. Most of these efforts use organic electroactive materials taking advantage of the structural diversity and tunability.1

Here we update the flow battery community with our recent development in nonaqueous flow chemistries. The first type is the hybrid lithium-organic flow battery, which uses Li-based anode and organic catholyte materials including ferrocene and TEMPO.2,3 High solubilities in the supporting carbonate electrolytes were obtained to TEMPO (2M) and structurally modified ferrocene (0.8M). Taking advantage of the low potential of the Li anode, cell voltages of ~3.5V were achieved. Consequently, these flow cells delivered high volumetric energy densities of 50Wh/L for ferrocene and 126Wh/L for TEMPO, respectively.
Because of the limitations of the Li anode, organic anolyte materials were explored coupled with another organic catholyte material in the second type. Cell voltages of >2V were obtained in these total-organic flow batteries. Electrolyte optimization was performed to achieve improved cycling stability and gain mechanistic understandings of capacity fading. The flow cell tests demonstrated remarkable cell efficiencies and high operational current densities that exceed those of most reported non-aqueous flow chemistries.

References

(1) Wang, W.; Luo, Q. T.; Li, B.; Wei, X. L.; Li, L. Y.; Yang, Z. G. Advanced Functional Materials
2013, 23, 970.
(2) Wei, X.; Cosimbescu, L.; Xu, W.; Hu, J. Z.; Vijayakumar, M.; Feng, J.; Hu, M. Y.; Deng, X.; Xiao, J.; Liu, J.; Sprenkle, V.; Wang, W. Adv Energy Mater
2014.
(3) Wei, X.; Xu, W.; Vijayakumar, M.; Cosimbescu, L.; Tianbiao, L.; Sprenkle, V.; Wang, W. Adv Mater
2014.

Figure 1
Liquid Catholyte Molecules for Non-Aqueous Redox Flow Batteries
Authors: Zhang Lu , Huang Jinhua , Cheng Lei , Assary Rajeev , Wang Peiqi , Xue Zheng , Burrell Anthony K. , Curtiss Larry 
Published: February 2020

Non-aquoes redox flow battery is a unique energy storage technology. Unlike traditional battery systems, the active energy storage material is in mobile phase and could basically be stored anywhere separately. This gives a lot of flexibility in terms of capacity, power and safety control, making it an idea candidate for large scale stationary energy storage application.
Material development for this technology is crucial for possible implementation. Molecular engineer of organic redox active molecules could lead to tunable physical and electrochemical properties, including solubility in organic solvents, molecular mobility, redox potential, and electrochemical reversibility, which are key factors to energy storage applications. A novel series of catholyte molecules, ANL-8, ANL-9, and ANL-10, has been developed by incorporation of PEO chains with different lengths on one or both sides of the dimethoxy-di-tert-butyl-benzene based redox structure. All of these molecules can afford electrochemically reversible behavior with similar redox potentials around 4.0 V vs Li/Li+. Due to the asymmetrical incorporation of PEO groups, ANL-8 and ANL-9 are found to be liquid at room temperature. The results from the diffusion, viscosity, DFT calculation, overcharge evaluation, and cell cycling indicate that ANL-8 is likely to be the best candidate among the redox active molecules in this study and does have promise to be a novel catholyte material for NRFBs. To our knowledge, it is the first time that the liquid catholyte molecules have been discovered for the application of NRFBs. The liquid nature of these catholyte molecules may open a new door to utilization of these molecules as the solo or co- solvents for high energy NRFB applications.
Solution Phase Catalysts for Lithium-Oxygen Batteries
Authors: Shen Yue , Huang Yunhui , Sun Dan 
Published: February 2020

A lithium-oxygen battery (LOB) would deliver the highest energy density of a rechargeable battery. But there is a central problem of catalytic action required for the rechargeable LOB: conventional solid state catalysts are not effective enough to catalyze the multiphase electrochemical reactions on the cathode side. The discharge product Li2O2 is also in solid state; it will accumulate at the catalyst surface and hence block the electrode reactions during the discharge process. Meanwhile, during the charging process, it is also difficult to make good contact between the solid catalyst and Li2O2. Therefore, instead of solid catalysts, some novel solution phase catalysts have been developed to solve the above problems1-3.
Here, we present a solution-phase catalyst, iron phthalocyanine (FePc), and provide a mechanism involving iron-oxygen coordination and a redox shuttle across the electrolyte4. The Fe-oxygen coordination and the electron dislocation in the big conjugated structure lowers the energy of the high energy intermediates in the ORR and OER. The dissolved FePc can act as a molecular shuttle of (O2)− species and electrons between the surface of electronically conducting carbon and product Li2O2 particles. With this novel approach, the formation and decomposition of Li2O2 is no longer confined to the carbon surface. The Li2O2blocking effect in the discharge process was greatly depressed. Meanwhile, the redox shuttle mechanism effectively lowers the overpotential during the charging process. Thus, the capacity and cyclability of the battery was improved dramatically.
Some other solution phase catalysts based on the redox shuttle mechanism, such as ferrocene-derived compounds and iodine, will also be discussed. The efficiency of various redox couples to oxidize the Li2O2during charging is compared with an oxygen monitoring method. We also show some evidence of side reactions caused by some certain redox shuttle compounds.
Reference:
(1) Y.H. Chen, S.A. Freunberger, Z.Q. Peng, O. Fontaine & P.G. Bruce, "Charging a Li-O-2 battery using a redox mediator". Nat. Chem., 2013, 5(6),489-494.
(2) H.-D. Lim, H. Song, J. Kim, H. Gwon, Y. Bae, K.-Y. Park, J. Hong, H. Kim, T. Kim, Y.H. Kim, X. Lepró, R. Ovalle-Robles, R.H. Baughman & K. Kang, "Superior Rechargeability and Efficiency of Lithium–Oxygen Batteries: Hierarchical Air Electrode Architecture Combined with a Soluble Catalyst". Angewandte Chemie International Edition, 2014, 53(15),3926-3931.
(3) B.J. Bergner, A. Schurmann, K. Peppler, A. Garsuch & J. Janek, "TEMPO: A Mobile Catalyst for Rechargeable Li-O2 Batteries". J. Am. Chem. Soc., 2014, 136(42),15054-15064.
(4) D. Sun, Y. Shen, W. Zhang, L. Yu, Z. Yi, W. Yin, D. Wang, Y. Huang, J. Wang, D. Wang & J.B. Goodenough, "A Solution-Phase Bifunctional Catalyst for Lithium–Oxygen Batteries". J. Am. Chem. Soc., 2014, 136(25),8941-8946.
Flower-like Nickel Sulfide As Efficient Electrocatalyst for Lithium Air Batteries
Authors: Ma Zhong , Yuan Xianxia , Li Lin , Ma Zi-Feng 
Published: February 2020

Lithium air batteries (Li-air batteries) can realize the reversible transport between chemical and electric energy by electrochemical reactions of lithium at the anode and air (O2) at the cathode, respectively1-3 and have ultrahigh theoretical specific energy (11140 Wh∙kg-1 excluding oxygen and 3505 Wh∙kg-1 if oxygen included)3
,
4. Therefore, they have attracted the widespread concern of electric vehicle industry and the relevant researchers.
However, Li-air technology is still remained at an early stage of development at this moment. Many problems, such as low specific energy, low round-trip efficiency, poor cycling life and rate capability hinder the practical applications of Li-air battery technology5
,
6. An efficient and stable cathode catalyst is one of most promising strategies to improve the performance of Li-air batteries7
,
8.
In this work, a novel flower-like nickel sulfide was synthesized via hydrothermal method and used as the efficient electrocatalysts for cathode of Li-air batteries. The flower-like NiS is a promising candidate as an efficient electrocatalyst for non-aqueousrechargeable Li-air batteries due to its good performance.

Acknowledgements

The authors are grateful for the financial support of this work by the National Science Foundation of China (21176155 and 21476138).

References

1. P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J.-M. Tarascon, Nat. Mater., 11, 19 (2012).
2. G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson and W. Wilcke, J. Phys. Chem. Lett., 1, 2193 (2010).
3. K. M. Abraham and Z. Jiang, J. Electrochem. Soc., 143, 1 (1996).
4. M. Armand and J. M. Tarascon, Nature, 451, 652 (2008).
5. A. C. Luntz and B. D. McCloskey, Chem. Rev. (2014), DOI: 10.1021/cr500054y.
6. J. Christensen, P. Albertus, R. S. Sanchez-Carrera, T. Lohmann, B. Kozinsky, R. Liedtke, J. Ahmed and A. Kojic, J. Electrochem. Soc., 159, R1 (2012).
7. Z. Ma, X. Yuan, L. Li and Z.-F. Ma, Chem. Commun., 50, 14855 (2014).
8. H. S. Jadhav, R. S. Kalubarme, J.-W. Roh, K.-N. Jung, K.-H. Shin, C.-N. Park and C.-J. Park, J. Electrochem. Soc., 161, A2188 (2014).
Analysis of the Aqueous/Solid Interface in a Mixed Aprotic/Aqueous Lithium-Air Battery
Authors: Uhlmann Christian , Braun Philipp , Illig Jörg , Ivers-Tiffée Ellen 
Published: February 2020

A rechargeable Li-air cell is promising due to its high theoretical energy density of about 11140 Wh/kg. A practical energy density of approximately 1000 Wh/kg [1] would be still about five times higher compared to a state-of-the-art Li-ion cell.
However, there are manifold problems concerning cell chemistry, reaction kinetics and cycleability of Li-air cells. In this study, a mixed aprotic/aqueous Li-air cell with a Li3xLa2/3-xTiO3 (LLTO) solid electrolyte was characterized in a new interface-cell setup. This setup is capable to analyse the polarization contribution caused by the liquid/solid interface between the solid electrolyte and different liquid electrolytes.
The cell design is inspired by Abe et al. [2], consisting of two compartments, which are in contact with the solid electrolyte. Four-point electrochemical impedance measurements are performed using two electrodes on both sides. The excitation signal is applied on the outer working electrodes (WE, CE) and the voltage is measured between the inner reference electrodes (RE1, RE2). The impedance spectra are further processed by calculating their distribution of relaxation times, to clearly separate the different processes [3].
The special cell design allows a selective investigation of a single liquid/solid interface process by assembling different symmetric cells, using the same liquid electrolyte in each compartment. By changing the ratio of conducting salt to solvent (Fig. 1), we clearly defined the interface process in a frequency range from 102 Hz to 103 Hz and determined an activation energy of 0,44 eV. Furthermore, the interface process is a major contribution to the overall polarization, which even exceeds the contribution of bulk electrolyte and grain boundary for low lithium concentration and low pH-value.
References:
[1] Jake Christensen et al., Journal of The Electrochemical Society, 159 (2) R1-R30 (2012)
[2] Takeshi Abe et al., Journal of The Electrochemical Society, 152 (11) A2151-A2154 (2005)
[3] Helge Schichlein et al., Journal of Applied Electrochemistry, 32 (8) 875-882 (2002)

Figure 1
TiO2 Nanotubes/Ionic Liquid Electrolyte System Enhances Li-Ion Battery Performance
Authors: Chu Peter Pojen , Tuan Jhen-Bin 
Published: February 2020

High capacity advanced lithium ion batteries (LIBs) utilizes non-volatile ionic liquid (IL) electrolyte is considered a promising candidate to address the safety and durability issues of traditional LIBs. Compared to organic-based electrolyte, however, IL has lower ionic conductivity at almost temperature range and shows less effective contact with the electrodes in absence of organic solvent, thus created barrier of lithium transfer at the electrolyte-electrode interface, which in turn reduce the cell performance
1
. Current study is focused on the design of composite ionic liquid electrolyte which gives higher ionic conductivity coupled with the improved of interface stability. Highly conductive electrolyte could be achieved through optimizing synergistic function between ionic liquids, salt, and the PVdF substrate. By suitable composition of lithium-bis-(trifluoromethyl sulfonyl)imide (Li-TFSI) and 1-butyl-3-methyl imidazolium bis-(trifluoromethyl sulfonyl)imide (BMI-TFSI) ionic liquids in poly-(vyniliden fluoride-hexafluoropropylene) (PVDF-HFP) co-polymeric host material, optimized membrane morphology is achieved through phase inversion technique during membrane casting, where an unique pore structure is formed. High ionic conductivity in the order of 10-3 Scm-2 is observed in PVDF-HFP: BMI-TFSI: Li-TFSI (10:10:2, w/w) electrolyte system, which is found to be higher than that of commercial membrane with liquid electrolyte. . Furthermore, the addition of small amount of TiO2 nanotubes (TiNT) incorporated onto the ionic liquid electrolyte system further raises the ionic conductivity up to ~1.5 x 10-3 Scm-2 (25 oC) and ~8.0 x 10-3 Scm-2 (80 oC), which is attributed both to higher lithium salt dissociation in presence of TiO2 and the establishment of more direct ion conducting pathway
2
. Further addition of TiNT, however, leads to reduction of ionic conductivity, which drops significantly after 5 wt% (relative to the solvent) of TiNT addition, which is probably the result of inorganic self-aggregation. Wider thermal decomposition around ~400 oC from TGA and DSC shows a remarkable improvement in thermal stability of membrane containing TiNT. Battery performance in a Li/electrolyte-TiNT/LiFePO4 coin cells indicates relatively high discharge specific capacity around ~136 mAh/g at 0.05 C moderate electrochemical cycling and shows better cycling performance with almost constant ~ 99% coulombic efficiency as a result of improved electrolyte interface stability to the electrode.
References:

Y. Kobayashi, Y. Mita, S. Seki, Y. Ohno, H. Miyashiro and N. Terada, J. Electrochem. Soc., 2007, 7, 677-681

H.K. Liu, G. X. Wang, Z. P. Guo, J. Z. Wang, and K. Konstantinov, J. New Mat. Electrochem. Systems, 2007, 10, 101-104
Specific Capacity and Capacity Fading of Interstitial and Substitutional Doping of Li in LiNi0.3Co0.3Mn0.3Ti0.1O2
cathode Material for High Energy Density Li-Ion
Authors: Rusdi Roshidah , Kamarulzaman Norlida , Elong Kelimah , Abd Rahman Azilah 
Published: February 2020

Pure and single phase LiNi0.3Co0.3Mn0.3Ti0.1O2 , Li1.05Ni0.3Co0.3Mn0.3Ti0.1O2 and Li1.05Ni0.3Co0.
25Mn0.3Ti0.1O2 materials were successfully prepared using a self-propagating combustion method. The structure and morphology of the materials were characterized using X-Ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and the elemental analysis were done using by Energy Dispersive X-Ray Spectroscopy (EDX). The oxidation state of element and their chemical environments were identified using X-Ray photoelectron Spectroscopy (XPS). The electrochemical performances of the materials were carried by means of galvanostatic charge-discharge test on the fabricated cells. XRD results showed that the materials are impurity-free and single phase with well ordered hexagonal layered structure of R-3m space group. The different samples annealed at 700 °C for 48h showed variations in discharge capacities. The discharge capacities are between 130 and 141 mAhg-1. The undoped LiNi0.3Co0.3Mn0.3Ti0.1O2 compound exhibits the highest first cycle capacity of 141.3 mAhg-1 over the voltage range of 2.5 to 4.2 V and the lowest capacity was 130.43 mAhg-1 for sample Li1.05Ni0.3Co0.
25Mn0.3Ti0.1O2. The 30th cycle revealed that the Li interstitially doped material is (Li1.05Ni0.3Co0.3Mn0.3Ti0.1O2) shows the highest specific discharge capacity of 131.74 mAhg-1. The capacity fading is only about 1.3% compared to 7.66% for undoped LiNi0.3Co0.3Mn0.3Ti0.1O2
and 12.3% for Li substitutionally doped material (Li1.05Ni0.3Co0.
25Mn0.3Ti0.1O2). The XPS studies showed that the binding energy of Li 1s is lowest for the best performance compound meaning that the Li+ ions can be extracted more easily from Li1.05Ni0.3Co0.3Mn0.3Ti0.1O2 than the other two materials. Therefore, XPS results show that the deintercalation of Li from the interstitially doped compound was much more efficient and enhanced the electrochemical performance of the material. The results also suggest that the self-propagating combustion method is a good synthesis method for the preparation of LiMn0.3Co0.3Ni0.3Ti0.1O2 and their Li doped materials for applications in lithium-ion batteries.
Electrochemical Performance of Full Concentration Gradient Cathode for Lithium-Ion Batteries
Authors: Wu Huiming , Xu Rui , Lu Jun , Amine Khalil 
Published: February 2020

Worldwide effort is being devoted to development of lithium-ion batteries for consumer devices, plug-in hybrid electric vehicles (PHEVs) and all-electric vehicles (EV), which require higher energy, increased safety, and lower cost. Most commercial lithium-ion batteries use a layered LiCoO2 as the cathode material, but LiCoO2has a limited practical capacity of about 140 mAh/g. A high capacity cathode material with high packing density is thus being sought to improve the energy density of lithium-ion batteries with improved safety.
Recently, some novel design structures cathode material are reported, such as core-shell, gradient material. First, a co-precipitation process is used to synthesize core-shell or gradient structure spherical precursor, then using this precursor to prepare a same structure cathode material. Using this new process, it is easy to control the elements distribution inside of single particles. This concept make it is possible to achieve the high capacity, cycling life and safety for a cathode material. So the composition design is based on those, high Ni in bulk material for high capacity and high Mn on the surface for safety with certain Co are investigated.
In this study, we investigated a full concentration gradient material, and the average composition is closed to Li1.0Ni0.6Co0.2Mn0.2O2. The material was synthesized by a solid-state reaction from full concentration gradient spherical precursor Ni0.6Co0.2Mn0.2(OH)2 and LiOH precursors. The full concentration gradient spherical precursor Ni0.6Co0.2Mn0.2(OH)2was prepared by a co-precipitation process. It exhibited uniform spherical particle shape with 15-mm diameter and high tap density of 2.7 g/cc. The electrochemical performance of the material was evaluated in a coin-cell. When the current density was 16 mA/g (C/10), the discharge capacities were about 191 mAh/g.
The significant improvement in tap density and the high capacity of this material makes it a potential cathode material for high energy battery application.

Acknowledgments

The authors acknowledge the financial support of the U.S. Department of Energy, FreedomCAR & Vehicle Technologies Office, under Contract No. DE-AC02-06CH11357.

Figure 1