bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iron Oxalates As Novel Electrode Materials for Li-Ion and Na-Ion Batteries
Authors: Yao Wenjiao , Armstrong Anthony Robert , Lightfoot Philip 
Published: February 2020

There is intensive research activity targeted on developing new electrode materials for the next generation of rechargeable lithium batteries, particularly for large-scale use in future hybrid electric or pure electric vehicles and in stationary energy storage of solar/wind power [1-3]. Polyoxyanion compounds are receiving considerable interest as cathodes since the strong binding of the oxygen enhances stability and thus safety, compared with transition metal oxides. The electronic inductive effect shifts the d-states of the transition metal ions and hence the redox potentials, providing a means of tuning the latter. Phosphate materials, particularly LiFePO4, have been extensively studied and continue to be important [2,3]. Recent work on oxalates by Tarascon and co-workers [4,5] has demonstrated the possible use of oxalate materials as a new class of polyoxyanion. Here we report the synthesis and characterization of hitherto-unknown alkali metal iron compounds in the oxalate system with new compositions and structures. The three dimensional framework structures were determined by single crystal X-ray diffraction, with an example shown in Fig. (a). All the materials displayed redox activity vs. either Li or Na, depending on the compound with stable cycling as shown in Fig. (b).
(1) B. L. Ellis, K. T. Lee and L. F. Nazar, Chem. Mater., 2010, 22, 691;
(2) J. B. Goodenough and Y. Kim, Chem. Mater., 2010, 22, 587.
(3) A. K. Padhi, K. S. Nanjundaswamy, and J. B. Goodenough, J. Electrochem. Soc. 1997, 144, 1188.
(4) H. Ahouari, G. Rousse, Y. Klein, J.N. Chotard, M.T. Sougrati, N. Recham, J.M. Tarascon. Solid State Sci. 2015, 42(6), 13.
(5) H. Ahouari, G. Rousse, J.R. Carvajal, M.T. Sougrati, M. Saubanere, M. Courty, N. Recham, J.M. Tarascon. Chem. Mater., 2015, 27, 1631.

Figure 1
Detection of Graphite Intercalation Compound Stages Using in-Operando 7Li NMR
Authors: Lorie Lopez Jose L. , Grandinetti Philip J. , Co Anne C. 
Published: February 2020

Operando spectra of a battery often consists of strongly overlapping resonances due to the compositional complexity and a mix of broad resonances. In the case of NMR spectroscopy, one could appeal to magic angle spinning (MAS) to remove some of these line broadenings and improve resolution. Unfortunately, eddy currents arising in metallic current collectors as well as in metallic electrode materials pose numerous experimental challenges.
Reported herein is an NMR method we developed that (1) improves the resolution of overlapping resonance which allows the identification of closely related features, but more importantly, the method (2) enhances the signals due to the formation and removal of species during the cycling of a battery. These spectra not only provide better resolution but also offer a more direct comparison of the species that are formed to the electrochemical current measured at each potential/time and reveal which spectra components are correlated to the chemical transformation at a specific potential.
Automotive Pouch Cell Performance: Effect of Silicon Loading, Binder, and Additives
Authors: Karulkar Mohan , Wen Hao , Blaser Rachel , Kudla Robert , Drews Andy 
Published: February 2020

As the auto industry looks towards increased electrification, there is a clear need for higher energy density batteries to increase vehicle range. One of the most promising next-gen anode materials is silicon, and indeed it is already being implemented in consumer electronic cells. [1] The first use in automotive cells will likely be lower-loading silicon in graphitic anodes. In anticipation of silicon incorporation in automotive applications, it is important to consider volume expansion of such cells. Existing automotive battery designs cannot accommodate significant volume expansion. There are also continuing concerns about cycle life and first cycle capacity loss. Factors like binder, electrolyte additives, and silicon content strongly affect performance metrics. [2]
To address these issues, 2 Ah and 4 Ah pouch cells were fabricated with NMC cathodes and various anode formulations, including 5% and 10% silicon in graphite, CMC/SBR and PAA binders, and with electrolytes containing 10% and 25% FEC additive. These cells were fabricated at the University of Michigan battery lab, and tests were conducted in-house. Design constraints, which will be discussed in this talk, limited N:P ratios to relatively high values (>1.5), which highlights challenges to designing full cells with high-SEI forming materials. PAA was found to produce 20% better capacity retention at 100 cycles, though that advantage lessened with continued cycling beyond 250 (Figures 1 and 2). Electrolyte with 10% FEC produced markedly better performance (40% + better retention) for the 5% silicon anodes. 25% FEC electrolyte produced better performance for higher-silicon anodes with 10% silicon. Volume expansion depended strongly on silicon content, but in no cases did cells swell by more than 2%, which is within current tolerances for pack design (Figure 3). The results point to future work with increased silicon content and more optimized N:P ratios that approach unity.
[1] X. Zuo, J. Zhu, P. Müller-Buschbaum, Y. Cheng, J. Power Sources, 31, 113-143 (2017).
[2] M. Karulkar, H. Wen, R. Kudla, R. Blaser, ECS Transactions, 72, 197-206 (2016).

Figure 1
Chemically Coupled Conducting Complex Framework Materials (C4FMs) As Sulfur Hosts in Lithium – Sulfur Batteries
Authors: Murugavel Shanthi Pavithra , Jampani Hanumantha Prashanth , Wang Louis S. , Gattu Bharat , Datta Moni Kanchan , Velikokhatnyi Oleg I , Kumta Prashant N 
Published: February 2020

Abstract
Ever increasing demand for efficient portable energy storage systems has directed researchers towards finding alternatives for the conventional insertion – based lithium-ion battery cathodes. Sulfur, with a theoretical specific capacity of 1672 mAh/g is a promising candidate for high energy density lithium battery cathodes1, 2. Low cost and ease of availability further adds to the advantages of sulfur over hitherto transition metal – based cathodes.
However, elemental sulfur has very low electronic conductivity (~10-15 S/cm)3 at room temperature which restricts the active material utilization in Li – S battery. The formation of soluble non – intercalation based polysulfide intermediates (Li2Sn; n = 2 – 8)4 during electrochemical cycling further results in active material loss by coating onto the anode leading to eventual battery failure.
Embedding sulfur into porous materials have shown considerable reduction in polysulfide dissolution by preventing direct contact with the liquid electrolyte5-7. However, inability to precisely control porosity and lack of chemical interaction between these porous structures and the entrapped sulfur greatly limits the efficiency of this approach. To completely prevent polysulfide dissolution, sulfur hosts with tunable, engineered porosity and increased affinity for polysulfide needs to be engineered.
In this work, chemically coupled conductive complex framework materials (C4FMs) with nanoporous structure were used as hosts for sulfur in Li – S battery. Introduction of special functional groups improves the affinity of these structures towards polysulfide. The frameworks were synthesized using microwave assisted hydrothermal synthesis and then infiltrated with sulfur using vapor infiltration techniques. These sulfur – hosted cathodes showed a stable electrochemical performance with an initial discharge capacity of ~1620 mAh/g which stabilized at 1100 mAh/g to100 cycles (Figure 1).
Acknowledgements: The authors acknowledge the financial support of DOE grant DE-EE 0006825, Edward R. Weidlein Chair Professorship funds and the Center for Complex Engineered Multifunctional Materials (CCEMM).
References
1. J. R. Akridge, Y. V. Mikhaylik and N. White, Solid State Ionics, 2004, 175, 243-245.
2. M. M. Thackeray, C. Wolverton and E. D. Isaacs, Energy & Environmental Science, 2012, 5, 7854-7863.
3. M. Edeling, R. W. Schmutzler and F. Hensel, Philosophical Magazine Part B, 1979, 39, 547-550.
4. S. S. Zhang, Journal of Power Sources, 2013, 231, 153-162.
5. S.-R. Chen, Y.-P. Zhai, G.-L. Xu, Y.-X. Jiang, D.-Y. Zhao, J.-T. Li, L. Huang and S.-G. Sun, Electrochimica Acta, 2011, 56, 9549-9555.
6. Z. Gong, Q. Wu, F. Wang, X. Li, X. Fan, H. Yang and Z. Luo, RSC Advances, 2016, 6, 37443-37451.
7. J. Jin, Z. Wen, G. Ma, Y. Lu and K. Rui, Solid State Ionics, 2014, 262, 170-173.

Figure 1
Structural Hybrid Supercapacitor
Authors: Wang Yuchen , Qiao Xiaoyao , Zhang Chen , Zhou Xiangyang 
Published: February 2020

Supercapacitors (SCs) have attracted tremendous attention due to their high specific power and long cycle life. The two major issues with SCs are low specific energy and self-discharge. The benefits of doping mediators or redox species in electrolytes include: 1) providing extra pseudocapacitance out of bulk of electrode materials, 2) increasing the electronic and ionic conductivities of electrolyte in the composite electrodes; and 3) releasing the ions into electrolyte to promote the capacity of electrolyte. Redox species or mediators as dopants in electrolytes are reported to realize the specific capacitance up to 400-500 F/g and the specific energy up to 30-50 Wh/kg. For the issue of self-discharge, adding primary cell materials into the mediator SC is proposed because the materials can provide a micro-current to compensate the self-discharge current. In this research, Cu powder/CuSO4 and Zn powder/ZnSO4 were added into the positive and negative electrodes respectively. The positive electrode also contained PVDF/LiTFS polymer electrolyte doped with K4Fe(CN)6 as mediator whereas the negative electrode contained PVDF/LiTFS doped with (VO)SO4 as mediator. A mixture of epoxy/PVDF/LiTFS thin film was used as the separator between the electrodes also to provide adhesion. Figure 1 shows the galvanostatic charge/discharge (GCD) curves of a structural hybrid SC. A cyclic voltammetry (CV) curve obtained at a scan rate of 10 mV/s of this hybrid SC is illustrated in Figure 2. The broad peak from 0.4V to 0.8V is an indication of pseudocapacitance behavior related to the redox reactions of the mediators. The asymmetric shape of CV curve is related to the electrochemical reactions of Cu and Zn during charging/discharging. It was found that the voltage of the SC can be withheld at 1V for more than 3 months. The mechanical strength of the SC was tested using a MTS machine. It was found that the elastic constant as 20 MPa and ultimate tension strength was 2 MPa.

Figure 1
2D Water-Coupled Metallic MoS2 with Nanochannels for Ultrafast Supercapacitor
Authors: Zhu Hongli , Geng Xiumei 
Published: February 2020

MoS2 is a promising electrode material for energy storage. However, the metallic, intrinsic multilayer, and pure MoS2 (M-MoS2) has not been investigated for use in supercapacitors. Here, an ultrafast rate supercapacitor with extraordinary capacitance using a multilayer M-MoS2-H2O system is first investigated. Intrinsic M-MoS2 with a monolayer of water molecules covering both sides of nanosheets is obtained through a hydrothermal method with water as solvent. The super conductivity of the as-prepared pure M-MoS2 is beneficial to electron transport for high power supercapacitor. Meanwhile, nanochannels between the layers of M-MoS2-H2O with a distance of ~1.18 nm are favorable for increasing the specific space for ion diffusion and enlarging the surface area for ion adsorption. By virtue of this, M-MoS2-H2O reaches a high capacitance of 380 F/g at a scan rate of 5 mV/s and still maintains 105 F/g at scan rate of 10 V/s. Furthermore, the specific capacitance of the symmetric supercapacitor based on M-MoS2-H2O electrodes retain a value as high as 249 F/g under 50 mV/s. These findings suggest that multilayered M-MoS2-H2O system with ion accessible large nanochannels and efficient charge transport provide an efficient energy storage strategy for ultrafast supercapacitors.
Novel Lead-Graphene Positive Grids for a Motive Power Lead-Acid Battery
Authors: Dai Guiping 
Published: February 2020

As a result of scientific and technological innovation over past decades, the number of graphene-based products is growing rapidly throughout the world. Lead-acid is the most widely employed rechargeable system with a 65% share of the market. Although the battery was invented over 150 years, research continues to enhance its performance in terms of rate capability, stability, cycle life and durability [1]. The use of graphene is envisaged to offer further benefits given that it has high intrinsic electrical conductivity and also is extremely lightweight, chemical inert and flexible with a large surface area. The presence of graphene in the electrodes improves the electrical conductivity between the particles of the active mass through preventing thickening and the growth of large lead sulfate particles [2]. This feature is attributed to the formation of a stable and conductive matrix that enables homogeneous delivery and distribution of current to all parts of the active material. By enabling a uniform current distribution, and subsequently well distributed electrochemical redox reactions throughout the electrode matrix, arrested the formation of too large lead sulfate particles. The addition of graphene is also considered to increase both the mechanical stability and electrical integrity of the electrodes and to induce uniform changes in the active mass during charge-discharge cycling. This presentation discusses the commercial application of novel lead-graphene positive grids in a motive power lead-acid battery designed for e-bike duty. The composite grids have been produced by Chaowei Power Ltd. And to date have been used successfully in over 30 million e-bike batteries. Graphene-lead composites have higher hardness, shorter ageing time and greater corrosion resistance compared with lead-calcium alloys presently employed in lead-acid batteries and thereby show promise for a new-generation of positive grids.
References
[1] Detchko Pavlov, Lead-acid batteries: science and technology (Book), Elsevier 2011.
[2] Mo Shi, Guiping Dai, et al., Synthesis of Graphene and application in lead-acid battery, Chinese LABAT Man, 2015; 52(3): 142-145.
(Invited) Processing and Applications of Monodisperse Two-Dimensional Nanomaterial Inks
Authors: Hersam Mark C. 
Published: February 2020

Two-dimensional nanomaterials have emerged as promising candidates for next-generation electronics and optoelectronics [1], but advances in scalable nanomanufacturing are required to exploit this potential in real-world technology. This talk will explore methods for improving the uniformity of solution-processed two-dimensional nanomaterials with an eye toward realizing dispersions and inks that can be deposited into large-area thin-films [2]. In particular, density gradient ultracentrifugation allows the solution-based isolation of graphene [3], boron nitride [4], montmorillonite [5], and transition metal dichalcogenides (e.g., MoS2, WS2, ReS2, MoSe2, WSe2) [6,7] with homogeneous thickness down to the atomically thin limit. Similarly, two-dimensional black phosphorus is isolated in organic solvents [8] or deoxygenated aqueous surfactant solutions [9] with the resulting phosphorene nanosheets showing field-effect transistor mobilities and on/off ratios that are comparable to micromechanically exfoliated flakes. By adding cellulosic polymer stabilizers to these dispersions, the rheological properties can be tuned by orders of magnitude, thereby enabling two-dimensional nanomaterial inks that are compatible with a range of additive manufacturing methods including inkjet [10], gravure [11], screen [12], and 3D printing [13]. The resulting printed two-dimensional nanomaterial structures show promise in several applications including photodiodes [14], anti-ambipolar transistors [15], gate-tunable memristors [16], and heterojunction photovoltaics [17,18].
[1] D. Jariwala, et al., ACS Nano, 8, 1102 (2014).
[2] E. B. Secor, et al., Journal of Physical Chemistry Letters, 6, 620 (2015).
[3] A. A. Green, et al., Nano Letters, 9, 4031 (2009).
[4] J. Zhu, et al., Nano Letters, 15, 7029 (2015).
[5] J. Zhu, et al., Advanced Materials, 28, 63 (2016).
[6] J. Kang, et al., Nature Communications, 5, 5478 (2014).
[7] J. Kang, et al., Nano Letters, 16, 7216 (2016).
[8] J. Kang, et al., ACS Nano, 9, 3596 (2015).
[9] J. Kang, et al., Proc. Nat. Acad. Sci. USA, 113, 11688 (2016).
[10] E. B. Secor, et al., Journal of Physical Chemistry Letters, 4, 1347 (2013).
[11] E. B. Secor, et al., Advanced Materials, 26, 4533 (2014).
[12] W. J. Hyun, et al., Advanced Materials, 27, 109 (2015).
[13] A. E. Jakus, et al., ACS Nano, 9, 4636 (2015).
[14] D. Jariwala, et al., Proc. Nat. Acad. Sci. USA, 110, 18076 (2013).
[15] D. Jariwala, et al., Nano Letters, 15, 416 (2015).
[16] V. K. Sangwan, et al., Nature Nanotechnology, 10, 403 (2015).
[17] D. Jariwala, et al., Nano Letters, 16, 497 (2016).
[18] T. A. Shastry, et al., ACS Nano, 10, 10573 (2016).
Ionic Solutions of Two-Dimensional Materials
Authors: Cullen Patrick Linden , Cox Kathleen M , Bin Subhan Mohammed K , Picco Loren , Payton Oliver D , Buckley David J , Miller Tom , Hodge Stephen A , Skipper Neal T , Tileli Vasiliki , Howard Christopher A 
Published: February 2020

Typical methods for forming liquid dispersions of nanoparticles rely on physical forces being applied to a system in which the reaggrigation is minimised through surface modification. Here we present a scalable method for synthesising undamaged two-dimensional nanosheets in solution. This is done by first intercalating a layered material with alkali metals to form layered material salts, that when simply added to polar solvent, form ionic solutions. The nanosheets made in this gentle manner maintain the morphology of the starting material, are stable against reaggregation and can create liquids containing exclusively monolayers. Electroplating allows for the removal of the charge from the anionic nanosheets and allows for controlled deposition upon the electrode. This method allows for the scalable production and controllable manipulation of 2d nanosheets.
Nanowire Templated Growth of Three-Dimensional Fuzzy Graphene
Authors: Cohen-Karni Tzahi , Garg Raghav , Rastogi Sahil , Nuhfer Thomas 
Published: February 2020

Graphene, a two-dimensional (2D) hexagonal arrangement of sp2
carbon, is gaining popularity as a material for electrochemical sensors. Graphene outstanding electrical properties has led researchers to develop three-dimensional (3D) atomic layer graphene materials with increased surface area as more efficient electrodes. Although 3D graphene materials such as foams and multilayered carbon nanowalls have already been synthesized, synthesis of 3D vertical atomic layer graphene still remains a challenge.
Here we demonstrate a novel synthesis of high density single to few layer vertical graphene on semiconductor nanowire mesh templates. The presence of graphene on the nanowires was confirmed by Raman spectroscopy. The progression of the templated growth of the 3D graphene flakes was verified by using scanning electron microscopy. Moreover, the growth of single to few layer crystalline graphene flakes that are vertically orientated with respect to the nanowire axis was validated by transmission electron microscopy. The sheet resistance of the new hybrid nanomaterial decreased with an increase in graphene flake size and density. Lastly, high electrochemically active surface area of the material was ascertained by cyclic voltammetry. These results pave way for the use of 3D vertical atomic layer graphene on nanowire mesh templates as electrodes for electrochemical sensing of biomolecules, quantification of fast-electron transfer reactions, and energy harvesting in fuel cells.
Excitonic Properties and Ultrafast Carrier Dynamics in 2D Hybrid Organic-Perovskites
Authors: Abdelbaki Katia , Diab Hiba , Lédée Ferdinand , Garrot Damien , Deleporte Emmanuelle , Lauret Jean-Sébastien 
Published: February 2020

Due to their high potentiality for photovoltaic applications or coherent light sources, a renewed interest in hybrid organic perovskites (HOPs) has emerged since 2012. HOPs can be arranged in such a way that carriers are free to move at 3D or at 2D. At 3D, the exciton binding energy has been shown to be of the order of tenth of meV. When they are arranged in two dimensions, these materials can be considered as hybrid multi-quantum wells [1], that lead to strong light-matter coupling regime when they are embedded in an optical microcavity [2-9]. Moreover, both quantum and dielectric confinement lead to a huge exciton binding energy of several hundreds of meV [1].
In this talk, we will focus on the excitonic properties of 2D HOP. In particular, we will report on ultrafast pump-probe experiments performed on (C6H5C2H4NH3)2PbI4 thin layers at room temperature [10]. The exciton dynamics is fitted with a bi-exponential decay with a free exciton life-time of ∼100 ps. The presence of a long tail in the pump/probe signal is attributed to trapped excitons on dark states, while an ultrafast intraband relaxation (tintra ≤ 150 fs) is reported. The analysis of the transient broadening and loss of oscillator strength demonstrates that 2D-HOPs share common behaviours with standard semiconductors quantum wells despite their huge exciton binding energy that is closer to the one reported for organic semiconductors.
References:
[1]K. Gauthron, JS Lauret, L. Doyennette, G. Lanty, A. Al Choueiry, S. J. Zhang, A. Brehier, L. Largeau, O. Mauguin, J. Bloch, and E. Deleporte, O Optic Express 18, 5912 (2010)
[2] A. Brehier, R. Parashkov, J.-S. Lauret and E. Deleporte, Appl. Phys. Lett. 89, 171110 (2006)
[3] G. Lanty, A. Bréhier, R. Parashkov, J. S. Lauret and E Deleporte New Journal of Physics 10, 065007 (2008)
[4] G. Lanty, J. S. Lauret, E. Deleporte, S. Bouchoule, and X. Lafosse Appl. Phys. Lett. 93, 081101 (2008)
[5] G. Lanty, S. Zhang, J. S. Lauret, E. Deleporte, P. Audebert, S. Bouchoule, X. Lafosse, J. Zuniga-Perez,
[6] F. Semond D. Lagarde, F. Médard, and J. Leymarie Phys. Rev. B 84, 195449 (2011)
[7] Zheng Han, Hai-Son Nguyen, Fabien Boitier, Yi Wei, Katia Abdel-Baki, Jean-Sébastien Lauret, Jacqueline Bloch, Sophie Bouchoule and Emmanuelle Deleporte, Optic Letters 37, 5061 (2012)
[8] Z. Han, HS Nguyen, F. Réveret, K. Abdel-Baki, J.S. Lauret, J. Bloch, S. Bouchoule, and E. Deleporte Appl. Phys. Express 6, 106701(2013)
[9] H. S. Nguyen, Z. Han, K. Abdel-Baki, X. Lafosse, A. Amo, J-S. Lauret, E. Deleporte, S. Bouchoule, and J. Bloch, Appl. Phys. Lett. 104, 081103 (2014)
[10] K. Abdel-Baki, F. Boitier, G. Lanty, K. Djemli, L. Galmiche, P. Audebert, E. Deleporte and J.S. Lauret
Journal of Applied Physics 119, 064301 (2016)