bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrolyte-Dependent SEI Formation and Its Consequences on Mg Electrode Cycling
Authors: Holc Conrad , Hopkinson Emily , Dimogiannis Konstantinos , Johnson Lee R
Published: December 2020

Recently, there has been significant research into magnesium batteries due to their potential as a beyond Li-ion technology. This is due to a number of beneficial properties of the Mg negative electrode, including high volumetric capacity, twice that of metallic Li (Figure 1) and lack of dendritic growth on cycling.1,2 However, current electrolytes are insufficiently stable to the Mg electrode, leading to reduction of the electrolyte and formation of a solid electrolyte interphase (SEI), which is believed to be detrimental to performance.3-7 Furthermore, a majority of reports have used noble metal electrodes to assess the suitability of electrolytes with Mg, which is not representative of the conditions in a practical Mg battery.8,9

Here, we probe the cycling behavior of bulk Mg electrodes in two electrolytes, one Grignard-based (BuMgCl in THF) and the other glyme ether-based (Mg(TFSI)2 in TEGDME). Cyclic voltammetry identified different plating and stripping behaviour in each electrolyte, with the Grignard demonstrating plating/stripping typical for a bulk electrode, while Mg stripping in the glyme ether resulted in a finite peak in the cyclic voltammetry. This unexpected result suggests a protective SEI forms on the Mg surface in the glyme ether, which critically still allows Mg-ion diffusion. The nature of the SEI in both electrodes was characterised using FTIR spectroscopy and SEM imaging, confirming that the nature of the SEI is dependent on the electrolyte and that it affects the way in which Mg electrodes cycle. Our results suggest that it is possible to protect Mg electrodes with a stable SEI and allow the use of electrolytes with increased oxidative stability.

Reference
s
:

[1] M. Matsui, J. Power Sources 196 (2011) 7048–7055.

[2] J. Song, E. Sahadeo, M. Noked, S. B. Lee, J. Phys. Chem. Lett. 7 (2016) 1736–1749.

[3] M.-S. Park, J.-G. Kim, Y.-J. Kim, N.-S. Choi, J.-S. Kim, Isr. J. Chem. 55 (2015) 570–585.

[4] S. Y. Ha, Y. W. Lee, S. W .Woo, B. Koo, J. S. Kim, J. Cho, K. T. Lee, N. S. Choi, ACS Appl Mater Interfaces 6 (2014) 4063–4073.

[5] I. Shterenberg, M. Salama, H. D. Yoo, Y. Gofer, J.-B. Park, Y.-K. Sun, D. Aurbach, J. Electrochem. Soc. 162 (2015) A7118-A7128.

[6] O. Tutusaus, R. Mohtadi, N. Singh, T. S. Arthur, F. Mizuno, ACS Energy Lett. 2 (2017) 224-229.

[7] M, S. Ding, T. Diemant, R. J. Behm, S. Passerini, G. A. Giffin, J. Electrochem. Soc. 165, (2018) A1983-A1990

[8] K. Ta, K. A. See, A. A. Gewirth, J. Phys. Chem. C 122 (2018) 13790–13796.

[9] J. G. Connell, B. Genorio, P. Papa, D. Strmcnik, V. R. Stamenkovic, N. M. Markovic, Chem. Mater. 28 (2016) 8268–8277.

Figure 1
Ether-Based Electrolytes Enabling Long-Stability High-Voltage Lithium-Ion Batteries
Authors: Jia Hao , Zhang Xianhui , Xu Yaobin , Burton Sarah D , Engelhard Mark H , Gao Peiyuan , Wang Chongmin , Xu Wu
Published: December 2020

In the pursuit of longer driving range per charge, the electric vehicle industry has significantly raised the energy density demands for lithium (Li)-ion batteries (LIBs). Two of the most feasible approaches to increase the energy density of LIBs are increasing the specific capacity of the cathode material, normally by using nickel-rich LiNixMnyCozO2 (x+y+z=1) such as NMC811, and elevating the charge cutoff voltage. However, energy density increase through such approaches are usually achieved at the cost of battery cycle life, as the state-of-the-art LiPF6-organocarbonate electrolytes are not compatible with such cell chemistry and testing condition. Here, we developed ether-based localized high-concentration electrolytes (LHCEs) in response to such challenges. It has been reported that the LHCEs based on 1,2-dimethoxyethane (DME) are capable of enhancing the anodic stability of the electrolytes up to 4.5 V vs. Li/Li+ by reducing the number of non-coordinated solvent molecules and forming effective solid electrolyte interphase on Li metal anode.1,2 The incompatibility of the ether electrolytes can be solved by adding small amount of functional additives, thus long-term cycling performance of graphite||NMC811 cells in the voltage of 2.5-4.4 V can be achieved. For instance, after 500 charge/discharge cycles at ambient temperature, the capacity retention of the graphite||NMC811 cells using an appropriate DME-LHCE reached 86.8%, while that of the cell with LiPF6-organocarbonate electrolyte only amounted to 75.8%. More detailed results and analyses will be discussed at the presentation.

References

X. Ren, et al., Joule, 2019, 3(7), 1662-1676.

X. Cao, et al., Nature Energy, 2019, 4(9), 796-805.
Slow Growth Approach for Lithium Ion Deposition on Lithium Metal Anode Surfaces
Authors: Angarita Gomez Maria , Balbuena Perla B.
Published: December 2020

Lithium metal anodes are indispensable for next-generation batteries including Lithium-Sulfur and Lithium-air batteries which show high promise for electric vehicles and other energy storage applications. Challenges such as extreme reactivity and lithium dendrite formation have kept lithium metal anodes away from practical applications. Lithium dendrite formation on anode surfaces during the charging process originates from the inhomogeneous deposition of metallic lithium during the electrochemical reduction of lithium cations. However, the underlying mechanisms of Li ion deposition from the electrolyte solution onto the anode surface are still poorly understood due to its inherent complexity. In this work, Density Functional Theory (DFT) simulations and thermodynamic integration calculations are conducted to study the electron and ion transfer between lithium metal slab and the electrolyte in absence of an external field. The slow growth approach allow the energy barriers on the diffusion and deposition pathway to be studied. This method illuminate the underlying mechanisms on lithium-ion deposition and provide a better understanding of the early stages of dendrite nucleation. We explore the effect of the solvent chemistry and structure, distance of the solvated complex from the surface, anion-cation separation, and concentration of Li-salts on the deposition of lithium ions from the electrolyte phase onto the surface. It is found that the structure and properties of the solvation shell around the lithium cation has a great influence on the ability of the cation to diffuse as well as on its surrounding electron environment.
A Multi-Analytical Approach for the Surface Reactivity Characterisation of Pristine NMC811: Towards Gassing Comprehension
Authors: Laurita Angelica , Cabelguen Pierre Etienne , Zhu Liang , Hamon Jonathan , Fernandez Vincent , Guyomard Dominique , Dupré Nicolas , Moreau Philippe
Published: December 2020

The urgent demand of the EV industry for high energy density cathode materials is currently leading the battery market towards Ni-rich NMCs. Despite that, the gassing phenomenon that affects these materials has huge impacts on their electrochemical properties and causes security issues that prevent the commercialization of 80% Ni-rich NMC.

In order to obtain a fundamental understanding of this gassing generation, we decided to focus on the surface reactivity of the pristine NMC811 provided by Umicore, with emphasis on the material surface’s and bulk’s changes during the native contamination layer formation. A multi-analytical approach is thus required to analyse all the aspects of such a complex system.

The sapient use of high field 7Li MAS-NMR allowed us to successfully filter the signal of the diamagnetic compounds at the surface of the material and to quantify the corresponding environments. The speciation of these compounds, not being possible by MAS-NMR, was defined by low temperature XPS experiments.

It was thence possible to characterise the reactive surface of the primary particles in contact with this contamination layer at the nanometric scale by STEM-EELS with both high energy and high spatial resolutions. The oxidation state and the crystalline phase were successfully determined crossing the high quality experimental spectra recorder with the K2 counting direct detector (Gatan) installed on our new Themis Z G3 (Thermo Fisher Scientific) and EELS edges simulations.

On the other hand, low field 1H MAS-NMR gave us a new insight on the proton environments enabling us to clearly see the presence of a proton chemically bonded inside the material for the first time and to correlate it with the surface reactivity investigated with the other techniques.

The combined use of these advanced characterisation techniques, all available in the IMN, allowed us to shed a new light on the understanding of the pristine industrial NMC811 with always the same material history.
Hard Carbon Ethylene Carbonate Interfaces – Atomic Scale Insight into Surface Termination, Defects, Functional Groups, and Roughness on Electrolyte Breakdown, Metal Adsorption, Intercalation and Nucleation
Authors: Olsson Emilia , Cai Qiong
Published: December 2020

In the search for post lithium ion batteries (LIBs), sodium ion batteries (NIBs) are gaining traction, but fundamental understanding of the atomic scale interactions at the anode electrolyte interfaces in NIBs remains poorly understood. In moving from LIBs, the LIB anode material graphite was found to be unsuitable for NIBs. Instead, hard carbon anode materials have arisen as one of the most promising electrode materials for sodium ion batteries (NIBs), which are also suitable for use with carbonate based electrolyte solvents. Hard carbons are complex amorphous carbon structures with randomly orientated, defective, and curved graphene nanosheets, and turbostratically stacked graphitic layers. This complex structure leads to a plethora of carbon structural motifs being present in the anode, leading to a large number of potential morphologies having to be taken into account when investigating the anode electrolyte interface.

In this study, we use ab initio molecular dynamics to investigate the effect of surface roughness, disorder, defects, and termination on the electrolyte anode interactions in the EC (electrolyte solvent) | hard carbon (anode) system. These simulations show that EC intercalation and breakdown is directly influenced by the carbon surface termination and surface roughness. Furthermore, defects were found to be more probable to form in terms of defect formation energies at strained and curved carbon morphologies. These defects were also found to have a direct impact on the sodium binding to the anode. The effect of all these different structural motifs on sodium adsorption, intercalation, and diffusion were simulated to form an understanding of the anode electrolyte interfacial reactions. One consequence of electrolyte molecule breakdown, but could also be an effect of anode synthesis method, is the presence of functional groups at the carbon surface. From density functional theory simulations of functional groups O, OH, NH2, and COOH at different carbon motifs (planar basal plane, H-terminated edges, and curved morphologies) we could show that O-functional groups from an energetical perspective are highly probable to form on these surfaces, and can act as favourable sodium storage sites. The hydroxyl group on the other hand were found to form inorganic NaOH compounds, which could contribute to irreversible capacity.

Acknowledgment

The financial support from EPSRC (Engineering and Physical Sciences Council) under the grant number EP/M027066/1, and EP/R021554/2, is acknowledged.
Molten Salt Electrolytes: Computational Analysis of Transport, Electrochemical Properties and Designing New Mixtures
Authors: Radhakrishnan Balachandran , Ravichandran Ashwin , Lawson John W
Published: December 2020

Electric aircraft propulsion has gained traction over the last decade due to possible high-energy density electrochemistries with reasonable cycle life and identification of non-flammable chemistries that can guarantee much better safety. Commercial Li-ion batteries cannot reach such high capacities because of weight limitations that arise from the widely used intercalation electrodes. Also, use of organic electrolytes make them highly susceptible to fire on exposure to air and humidity. Currently, use of Lithium metal anode along with conversion electrochemistries such as Li-O2 and Li-S are being pursued to achieve such high energy densities. Safer inorganic solid-state electrolytes, recently discovered Water-in-Salt electrolytes, molten salt electrolytes are some of the alternatives being pursued for a safer/non-flammable battery.

Of these safer alternatives, molten-salt electrolytes offer some attractive properties: liquid at operating temperatures resulting in better electrode-wetting, stable interface with Li-metal anodes and good ionic conductivity; their only drawback being high operating temperatures. In this talk, we will discuss some of the computational studies, driven via atomistic simulations, of the properties of molten-salt electrolytes including transport mechanism and interface stability. We will also discuss predicting electrochemical properties of these high-temperature electrolytes. Further, we will discuss a thermodynamic approach to predicting new molten-salt eutectics with lower melting points.
Characterization and Modeling of Electrochemically Driven Natural Convection
Authors: Mohr Robert , Steingart Daniel A.
Published: December 2020

Natural convection arises in many types of fluid flow where a diffusive species causes a density change to the fluid. Electrochemical reactions are typically strong drivers of this flow given the combination of a large density change due to reaction and a relatively slow rate of species diffusion. Density stratification in lead-acid batteries is a well documented phenomenon, but the effect of density driven flow is not typically investigated in many electrochemical systems where it is a surprisingly important transport mode. Experiments and models show that a zinc-bromine cell's performance is dominated by this natural convection effect and results in a much higher utilization than would be expected based solely on a diffusive model. Finally we show how electrolyte composition can substantially modify the properties of this flow and how this can potentially benefit other systems.
Mg-Coated Si Thin Film As Model Electrode for Mechanistic Study of Li-Mg-Si Zintl Phase Formation in Lithium-Ion Batteries
Authors: Li Zhifei , Stetson Caleb , Teeter Glenn , Norman Andrew G , Ha Yeyoung , Tremolet de Villers Bertrand , Huey Zoey , Han Sang-Don , Jiang Chun-Sheng , Burrell Anthony , Zakutayev Andriy
Published: December 2020

Silicon (Si) is a promising anode material for high energy density lithium-ion batteries (LIBs) but its poor cycling performance prevents its large-scale adoption. Introducing Mg salt into the electrolyte has shown to form a ternary Li-Mg-Si Zintl phase upon lithiation of Si and improve the cycling stability; however, its formation mechanism and impacts on the solid electrolyte interphase (SEI) are not yet well understood. Herein, we demonstrate the formation of a ternary Li-Mg-Si Zintl phase via a Magnesium (Mg) coated Si thin film electrode, where Mg diffuses into the Si film upon deposition and in the lithiation process. The Zintl phase alters the nature of SEI, suppresses the excess decomposition of electrolyte and improves the capacity retention of the Si anode. This study provides insights into the formation mechanism of ternary Zintl phase and guidelines for the future design of Si anodes.
First Demonstration of the Improvement of Metal/High-K Interface Roughness Utilizing in-Situ NH3/N2 Remote Plasma Preferred: Poster
Authors: Huang Ping , Chang Edward Yi , Luc Quang-Ho , Ko hua Lun , Wu Jing Yuan , Hsu Che Wei , Tran Nhan Ai
Published: December 2020

In this work, we demonstrate a high-k/III-V gate stack interface treatment utilizing NH3/N2 in-situ remote plasma (RP). Through such treatment, the density of interface trap states (Dit) is dramatically reduced and the surface morphology of the Al2O3 is modified. Aside from the sharp decline in the Dit, the Al2O3 layer becomes smoother and thus results in a significant enhancement in the surface roughness mobility combining the observations from experiment as well as simulation results. From the Atomic Force Microscope (AFM) we observe an improvement of surface roughness from 0.332 nm to 0.252 nm. Also, we found a considerable enhancement in the surface roughness mobility from 7 x 1024 to 1.5 x 1026 cm2/Vs. Moreover, the mid-gap trap decreases from 5.7 x 1012 to 1.8 x 1012 cm-2/eV-1, which once again emphasis the achievements of this work.
The Importance of Competitive Solvent and Anion Coordination for Multivalent Battery Electrolytes
Authors: Hahn Nathan T , McClary Scott A , Zavadil Kevin R
Published: December 2020

Multivalent battery concepts based on magnesium or calcium metal anodes have the potential to provide higher energy density than traditional lithium ion batteries. However, current multivalent electrolytes possess less than optimal compatibility with these reactive metals and with desirable high voltage cathode materials. Understanding the origin of these issues requires an understanding of multivalent cation coordination environments in both the bulk and at the relevant interfaces. In this presentation, elucidation of the relative coordination strengths of “state-of-the-art” multivalent battery salts and solvents will be described. Moreover, the impact of these competitive coordination tendencies on metal deposition efficiency will be discussed along with the efficacy of tuning such interactions to improve magnesium and calcium electrolyte performance.

This work was supported by the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
(Invited) Tailored Design of Polymer Electrolytes for Advanced High-Capacity and High-Voltage Lithium Batteries
Authors: Chen Zhen , Steinle Dominik , Nguyen Huu-Dat , Mayer Alexander , Liang Hai-Peng , Dong Xu , Paillard Elie , Iojoiu Cristina , Passerini Stefano , Bresser Dominic
Published: December 2020

For decades, the use of polymer-based lithium battery electrolytes has been restricted to cells containing low-voltage positive electrodes such as LiFePO4, which intrinsically limited the achievable energy density. On the other hand, the employment of polymer electrolytes allowed for the use of lithium metal negative electrodes, even though the operation remained limited to elevated temperatures due to the relatively low ionic conductivity at room temperature.1,2 Accordingly, if these two challenges, i.e., the limited stability towards oxidation and the poor ionic conductivity, could be overcome, polymer-based electrolytes may pave the way towards high-energy lithium-metal batteries – one of the main targets of global battery research activities.3,4

Herein, we report our latest achievements in this field, specifically for single-ion conductors, as they additionally provide highly homogeneous lithium deposition and suppress the detrimental occurrence of reversed cell polarization upon cycling.2,5 These achievements include the design of polymer electrolytes with enhanced single-ion conductivities of about 10-3 S cm-1 at 30 °C as well as excellent stability towards lithium metal and high-energy next generation cathode materials like Li(Ni0.8Mn0.1Co0.1)O2 – up to anodic cut-off potentials as high as 4.5 V. As a result, these new single-ion conducting polymer electrolytes allow for highly stable cycling of such cells at 20 °C and even 0 °C.6,7 We hope that this work will trigger further research efforts also in other labs to boost the development of advanced lithium-polymer batteries.

References

J. Kalhoff, G. G. Eshetu, D. Bresser, and S. Passerini, ChemSusChem, 8, 2154–2175 (2015).

D. T. Hallinan and N. P. Balsara, Annu. Rev. Mater. Res., 43, 503–525 (2013).

X.-B. Cheng, R. Zhang, C.-Z. Zhao, and Q. Zhang, Chem. Rev., 117, 10403–10473 (2017).

Y. Guo, H. Li, and T. Zhai, Adv. Mater., 29, 1700007 (2017).

H. Zhang et al., Chem. Soc. Rev., 46, 797–815 (2017).

H.-D. Nguyen et al., Energy Environ. Sci., 11, 3298–3309 (2018).

Z. Chen et al., submitted manuscript.
(Invited) Designing New Electrolytes for High-Energy Lithium Metal Batteries
Authors: Xu Wu , Ren Xiaodi , Cao Xia , Gao Peiyuan , Zhang Ji-Guang
Published: December 2020

Lithium (Li) metal batteries with conventional nickel-rich transition metal oxide cathodes have been regarded as one of the next-generation high-energy rechargeable battery systems because the Li metal anode has an ultrahigh theoretical specific capacity (3860 mAh g-1) and a very low standard electrochemical redox potential (-3.040 V). However, two major problems associated with Li metal anode ¾ Li dendrite growth during repeated cycling and low Li Coulombic efficiency still hinder the application of rechargeable Li metal batteries, although great progresses have been made in stabilizing Li metal anode in the past decade, including smoothening Li deposition morphology and increasing Li Coulombic efficiency. Among these progresses, the development of novel electrolytes is one of the most important things, which can not only enable Li metal anode to reach high Li Coulombic efficiency of 99.5%, but also stabilize high voltage cathodes up to 4.5 V. In this presentation, the designing principles of solvating solvents and diluents in a new class of electrolytes called localized high-concentration electrolytes for high-energy Li metal batteries will be reported. The mechanisms for the performance advancements by the new electrolytes will also be discussed, especially through the Li/electrolyte and cathode/electrolyte interphases.
Electrodeposition of Cobalt in a Pyrrolidinium-Based Ionic Liquid Under a Magnetic Field
Authors: Manjum Marjanul , Serizawa Nobuyuki , Katayama Yasushi
Published: December 2020

Cobalt (Co) is well-known as a hard-magnetic material for its tailorable magnetic properties. Nowadays, a pyrrolidinium-based ionic liquid, composed of 1-butyl-1-methylpyrrolidinium (BMP+) and bis(trifluromethylsulfonyl)amide (TFSA–), has drawn more attention for the electrodeposition of various transition metals because of its wide electrochemical potential window, acceptable ionic conductivity, and high stability against moisture. Although the redox reaction of Co species has been reported in BMPTFSA, the electrochemical behavior of Co species under a magnetic field has not been explored in this ionic liquid.1-3 In this study, the electrodeposition of Co has been performed in BMPTFSA under a static magnetic field.

Co(TFSA)2 was prepared by the reaction of CoCO3 with HTFSA. A Teflon made, double compartment cell was used for the electrochemical measurements using a glassy carbon (GC) as a working electrode, a platinum mesh as a counter electrode, and a silver wire immersed in BMPTFSA containing 0.1 M AgCF3SO3 as a reference electrode. A neodymium magnet (NdFeB) was attached to the back of the GC electrode. The diameter of the magnet was 6 mm and the magnetic flux density was 530 mT.

Potentiostatic cathodic reduction applying –1.6 and –2.0 V was conducted under the magnetic field in BMPTFSA containing Co(TFSA)2 at 25 °C. Nanowire-shaped deposits were obtained on the GC electrode after the electrodeposition at both potentials. The presence of Co in the deposits was confirmed by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. However, no diffraction peak was observed in the deposits by X-ray diffraction. The deposits were further examined by transmission electron microscopy. The lattice fringe corresponding to (111) plane of Co was found in the deposits, indicating the deposits were composed of metallic Co nanoparticles.

References

(1) R. Fukui, Y. Katayama, and T. Miura, Electrochemistry, 73, 567 (2005).

(2) Y. Katayama, R. Fukui, and T. Miura, J. Electrochem. Soc., 154, D534 (2007).

(3) Y. Katayama, R. Fukui, and T. Miura, Electrochemistry, 81, 532 (2013).
Rational Design of Electrolyte and Interphase Formation for Solid-State Batteries
Authors: Deng Tao , Zhang Ji-Guang , Wang Chunsheng
Published: December 2020

Solid-state batteries (SSBs) using inorganic solid-state electrolytes (SSEs) are widely regarded as the next-generation energy storage system, which may replace the state-of-the-art Li-ion batteries with flammable organic electrolytes. However, the interfacial issues, including large interfacial resistance and dendrite generation, have always frustrated the development of high-energy SSBs. For the first time, we report that infusing the garnet-type Li-ion solid electrolytes (GSEs) with air-stable electrolyte Li3PO4 (LPO) dramatically reduces the interfacial resistance to ~1 Ω cm2 on anode side and achieves a high critical current density of 2.2 mA cm-2 under ambient condition due to enhanced interfacial stability to Li metal anode. The coated and infused LPO electrolytes not only improve the mechanical strength and Li-ion conductivity of grain boundaries, but also form a stable LPO-derived solid-electrolyte interphase between Li metal and GSEs, which eliminates the Li dendrites growth and prevents the direct reduction of GSEs by Li metal over a long cycle life.

Relying on the gained interface mechanisms, we further designed a new type of low-temperature beta-alumina solid electrolyte-based Na metal battery which has low interfacial impedance and extremely high critical current density for fast charging and discharging, outperforming all other types of solid or semi-solid state batteries to date. Overall, the interface engineering approaches together with grain-boundary modification on SSEs represent the promising strategy to revolutionize the electrode-electrolyte interface chemistry for SSBs and provides new design strategy for other-types of solid-state batteries.

References:

[1] T. Deng, X. Ji, Y. Zhao, L. Cao, S. Li, S. Hwang, C. Luo, P. Wang, H. Jia, X. Fan, X. Lu, D. Su, X. Sun, C. Wang, J.-G. Zhang, Tuning the anode-electrolyte interface chemistry for garnet-based solid-state Li metal batteries.
Adv. Mater.
, (2020), 2000030.

[2] T. Deng, X. Ji, H. Chang, L. Zou, X. Fan, L. Cao, H. Wang, B. Li, X. Li, C. Wang, D. Reed, J.-G. Zhang, V. Sprenkle, C. Wang, X. Lu, in revision.
Enhanced Performance of All-Solid-State Na-Ion Batteries
Authors: Tanaka Ayumu , Tsunoda Kei , Ikejiri Junich , Yamauchi Hideo , Sato Fumio , Sakamoto Taichi , Ikeuchi Yuuta , Tanaka Hideaki , Senoh Hiroshi , Honma Tsuyoshi , Komatsu Takayuki
Published: December 2020

All-solid-state Na-ion batteries (Na-ASSBs) with an oxide solid electrolyte have been successfully developed using crystallized glass as the cathode active material. Melt flow during the crystallization of the precursor glass enables the cathode to be integrated with a solid electrolyte. Such a effectively integrated cathode/solid electrolyte shows excellent battery performance and high cycling stability.

All-solid-state batteries with an oxide solid electrolyte are more thermally stable and safer than conventional lithium-ion batteries with an organic liquid electrolyte. In addition, owing to the use of Na, which is abundant natural resources, Na-ASSBs can be manufactured stably without the risk of resource shortage. Therefore, we believe that Na-ASSBs are among the most promising next-generation energy storages with high safety and large capacity. β”-alumina is a common oxide solid electrolyte with high ion conductivity comparable to the organic liquid electrolyte. If β”-alumina can replace organic electrolytes, safer Na-ASSBs operating over a wide temperature range can be fabricated. However, it is difficult to establish effective contact between the cathode material and the oxide solid electrolyte.

In this work, we focused on Na-ASSBs using Na2FeP2O7 crystallized glass as the cathode. [1,2] Na2O-Fe2O3-P2O5 precursor glass powder, β”-alumina powder, and acetylene black were mixed to prepare a cathode mixture, which was applied on a β”-alumina substrate, followed by heating to sinter and crystallize the glass. As a result, the solid electrolyte and cathode were successfully integrated. Then, Na metal was attached to the counter side as the anode. The Na-ASSB with such effective integration showed rapid charge/discharge performance (10C) even at room temperature, which in turn enabled the motor to be operated at room temperature (Fig. 1). Furthermore, the cycle performance test at 10C rate and 30°C showed that the capacity retention after 1000 cycles was 94%. The excellent battery performances allow for the practical application of Na-ASSBs. This presentation will focus on the performance of Na-ASSBs and the manner in which it can be realized.

References

[1] T. Honma et al., J. Ceram. Soc. Jpn. 120 (2012) 344-346.

[2] T. Honma et al., J. Power Sources 227 (2013) 31-34.

[3] H. Yamauchi et al., J. Am. Ceram. Soc. 102 (2019) 6658-6667.

[4] H. Yamauchi et al., (In press). Enhanced rate capabilities in a glass-ceramic-derived sodium all-solid-state battery. Sci. Rep.

Figure 1
Enhancing Electrode/Electrolyte Interfacial Stability in Solid State Lithium Batteries By Surface Coating
Authors: Yang Yuan
Published: December 2020

Interfacial stability is critical to the performance of solid-state batteries. Various promising solid electrolytes are unstable with either cathode or anode, such as polyethylene oxide (PEO) electrolyte with 4 V layered oxides, and sulfide electrolyte / LATP / LAGP with lithium metal. Such incompatibility limits the performance and commercialization of solid state batteries. In this talk I will present recent studies on improving interfacial stability of 4 V cathode/PEO interface and LATP/Li interface. At the 4 V cathode/PEO interface, by modifying the surface with LAGP nanoparticles and using LiBOB salt, PEO oxidation is suppressed. 85% capacity retention after 200 cycles is achieved in LCO/PEO/Li cell with a voltage range of 3-4.3 V. Compatibility with NCM523 (~94%/100 cycles) is also demonstrated. At the LATP/lithium interface, a nanoscale boron nitride coating blocks electron transfer and can significantly enhance the stability between LATP and lithium. Long cycle life of 500 cycles is achieved in LiFePO4/LATP/BN(PEO)/Li cells.
Room-Temperature Cycling of 4 V Hydroborate-Based All-Solid-State Sodium Battery Stabilized By a Self-Forming Cathode/Solid Electrolyte Interphase
Authors: Asakura Ryo , Reber David , Duchêne Léo , Remhof Arndt , Hagemann Hans , Battaglia Corsin
Published: December 2020

Room-temperature operation of high-voltage all-solid-state batteries requires solid electrolytes that combine high cation conductivity (≥1 mS cm−
1), a wide electrochemical stability window, and intimate electrode/solid electrolyte interfaces. However, none of the solid electrolytes has fulfilled these material properties so far. Hydroborates, a yet underexplored class of solid electrolytes,1 are highly conductive at room temperature and compatible with lithium and sodium metal anodes; however, the discharge cell voltage was limited up to 3 V in previous reports,2,
3 mainly due to the electrochemical oxidative stability of the solid electrolytes.4

Here we show that a hydroborate solid electrolyte, consisting of two kinds of hydroborate anions with different oxidative stability limits, can be effectively stabilized in contact with a 4 V-class cathode.5 At high voltages, the less stable anions tend to form a passivating interphase layer upon electrochemical oxidation at the cathode/solid electrolyte interface, while the more stable anions remain intact in the interphase layer, maintaining cation conduction. The self-forming interphase enables the first stable cycling of a 4 V-class hydroborate-based all-solid-state battery employing a sodium metal anode and a cobalt-free, high-voltage cathode. The cells exhibit a discharge capacity of 100 mAh g−1 at C/5 and an excellent (>85%) capacity and energy retention after 500 cycles at room temperature. Applying external pressure enables a discharge capacity of >110 mAh g−1 at C/10 with a high areal capacity close to 1.0 mAh cm−2. This work records the highest discharge cell voltage and specific energy (>440 Wh kg−
1) among all reported all-solid-state sodium batteries, demonstrating the attractive material properties and potential of hydroborates which surpass well-investigated oxides and sulfides as solid electrolytes for high-voltage all-solid-state batteries.

References

L. Duchêne, A. Remhof, H. Hagemann, and C. Battaglia, Energy Storage Mater., 25. 782–794 (2020).

L. Duchêne, D. H. Kim, Y. B. Song, S. Jun, R. Moury, A. Remhof, H. Hagemann, Y. S. Jung, and C. Battaglia, Energy Storage Mater., 26, 543–549 (2020).

S. Kim, H. Oguchi, N. Toyama, T. Sato, S. Takagi, T. Otomo, D. Arunkumar, N. Kuwata, J. Kawamura, and S. Orimo, Nat. Commun.
10, 1081 (2019).

R. Asakura, L. Duchêne, R.-S. Kühnel, A. Remhof, H. Hagemann, and C. Battaglia, ACS Appl. Energy Mater., 2, 6924−6930 (2019).

R. Asakura, D. Reber, L. Duchêne, A. Remhof, H. Hagemann, and C. Battaglia, submitted
Electroanalytical Characterization of the Interphase between the Solid Electrolyte Lipon and Li Metal
Authors: Westover Andrew S , Sacci Robert , Dudney Nancy J.
Published: December 2020

Solid-state electrolytes have the potential to enable high energy density batteries with Li metal anodes. The interphase between the Li metal and the electrolyte is one key to realizing Li metal anodes. One of the most successful solid-state electrolytes is lithium phosphorus oxynitride or Lipon which enables thin film Li metal batteries with high cycle life, energy density and power density. Despite its success, the interphase has not been well characterized. In this study we present a careful electroanalytical characterization of the Li metal-Lipon interphase formation. This interphase forms when Li first contacts the solid electrolyte. Using a Li metal/Lipon/Ni foil cells we determine that less than 5.0 ± 0.8 nm of Li is lost when it first contacts Li metal forming the interphase. Assuming all this Li is lost to the formation of a dense interphase, the thickness would be ~4.7 nm. We also show that this technique can be utilized to characterize the interphase that forms between Li metal and a variety of solid-state electrolytes.

This work was supported by the ARPA-E IONICS program, U.S. Department of Energy, award DE-AR0000775 and the U.S. Department of Energy Vehicle Technology Office US-German research program
High-Performance Solid-State Lithium-Ion Battery with Mixed 2D and 3D Electrodes
Authors: Ashby David , Choi Christopher S , Edwards Martin A. , Talin A. Alec , White Henry S. , Dunn Bruce S.
Published: December 2020

It is well established that the miniaturization of batteries has not kept pace with the miniaturization of electronics. Three-dimensional (3D) batteries, which were developed with the intent of improving microbattery performance, have had limited success because of fabrication challenges and material constraints. Solid-state, 3D batteries have been particularly susceptible to these shortcomings. In this paper we demonstrate that the incorporation of a high conductivity, solid electrolyte is the key to achieving a non-planar solid-state battery with high areal-capacity and high power-density. The model, 2.5D platform used in this study is a modification of the more typical 3D configuration in that it is comprised of a cathode array of pillars (3D) and a planar (2D) anode. This 2.5D geometry exploits the use of a high conductivity, ionogel electrolyte (10-3 S cm-1) which interpenetrates the 3D electrode array. The 2.5D battery offers high areal energy densities from the post array while the high-conductivity, solid electrolyte enables high power densities (3.7 mWh cm-2 at 2.8 mW cm-2). The reported solid-state 2.5D device exceeds the energy and power densities of any 3D solid-state system and the derived multiphysics model provides guidance for achieving significantly higher energy and power densities.
Effectively Suppressed Short Channel Effects Use Nitrogen-Passivated of Ingaas Gate-All-Around Mosfets for High Switching Speed Logic Application
Authors: Ko hua Lun , Luc Quang Ho , Chen Si-Meng , Huang Ping , Wu Jing Yuan , Hsu Che-Wei , Tran Nhan Ai , Chang Edward Yi
Published: December 2020

In this paper, we have fabricated an In0.53Ga0.47As gate-all-around field-effect-transistor (GAAFET) used N2 remote-plasma passivated. Transistors with Nitrogen passivated effectively suppressed short channel effect compared the controlling sample. We not only used the Nitrogen passivated but also fabricated the 9 nm top width and the near vertical sidewall of the GAA structure to enhance the gate controllability efficiency. In our results, subthreshold swing (SS) decreases from 81 to 66 mV/dec, drain induced barrier lowing (DIBL) reduces from 100 to 42 mV/V. In-situ N2 post remote plasma passivated is implemented to improve the interface of the high-k and semiconductor to suppress the short channel effect. In0.53Ga0.47As GAA FET with the Nitrogen-passivated is a promising candidate for low-power high switching speed logic application.
Completely Additive Manufactured and Reusable Microfluidic Device As Enzymatic Glucose Biofuel Cell
Authors: U S Jayapiriya , Rewatkar Prakash , Goel Sanket
Published: December 2020

Energy devices using electrochemical reactions are emerging as essential power sources, paving the way towards renewable and sustainable energy harvesting. Among various electrochemical energy devices (ECD), enzymatic biofuel cells (EBFC) are gaining more attention due to the production of green energy using biocatalysts such as enzymes and physiological fluids as fuel. These devices are of prime importance because of their unique features, such as high energy density, long-life, portability, and cost-effectiveness. However, they still have some drawbacks including precise and customized designing of devices at the microscale dimensions. This can be overcome by additive manufacturing techniques such as fused deposition modeling (FDM) driven 3D printing to produce accurate micro-devices using conductive filaments with tailored design. In this work, the development of a completely additively manufactured (AM) microfluidic device for the application of enzymatic biofuel cells has been described. The micro-device was 3D printed with ABS filament, whereas the electrodes using conductive graphene/polylactic acid filament using a desktop 3D printer. The design of the electrodes (Figure 1a) (35 mm × 1.5 mm × 1 mm) and microchannel were carried out using Autodesk Fusion 360 software with the required dimensions. Surface modification of the electrode was accomplished using dimethylformamide (DMF) for an optimized time of 10 mins (Figure 1b) and left to air dry overnight. The anodic (glucose oxidase) and cathodic (laccase) enzymes were immobilized on the bioelectrodes by the EDC-NHS coupling mechanism (Figure 1c and 1d). The substrate (glucose) concentration and DMF treatment time were optimized by various trials using electrochemical techniques. The microfluidic device was designed in a way that the device can be reused by inserting bioelectrodes into the respective compartments. The anolyte and catholyte consisted of mediators for enhancing the electron transfer rate during electrolysis. Co-laminar flow was maintained in the device to make it membraneless. This was done by varying the device design parameters and flow rates of the electrolyte with the help of a peristaltic pump. The sequential steps of integration of the bioelectrodes into the microchannel is shown in Figure 1e. Polarization performance of the fabricated bioelectrodes incorporated in the AM microfluidic EBFC was recorded using Chronoamperometry technique at the room temperature. The device was capable of generating a benchmarked power density of 7.95 µW/cm2 with an open circuit voltage of 312 mV. This method of device fabrication for EBFC will help in development of highly efficient ECD by different conductive electrode materials for increasing the efficacy of the micro-device.

Figure 1
PtRu Nanoparticles on Nitrogen-Doped Carbon Nanotubes As Efficient Anode for High Performance Direct Methanol Fuel Cells
Authors: Sekar Archana , Metzger Nathaniel , Elangovan Ayyappan , Li Xianglin , Li Jun
Published: December 2020

Growing energy demand has attracted the investigation of renewable energy conversion devices such as Direct Methanol Fuel Cells (DMFCs). It has several advantages as energy conversion device due to the low cost, higher energy density (6.08 kWh/kg) and easy handling of methanol. In DMFCs, methanol is oxidized to CO2 at the anode and oxygen is reduced to water at the cathode to produce electricity. Platinum (Pt) supported on Vulcan carbon is the state-of-the-art electrocatalyst for Methanol Oxidation Reaction (MOR). Conventionally, DMFCs cannot be fed with pure methanol as fuel, owing to the methanol crossover through polymer electrolyte membrane to the cathode side. However, using dilute methanol solutions causes the deliverable power density substantially lower than the theoretical value. In addition, the high cost of Pt, sluggish MOR kinetics and CO poisoning also hinder the commercialization of DMFCs. Therefore, design and development of robust anode materials are of compelling necessity. To address these issues, typically an oxophilic metal like Ruthenium (Ru) is alloyed with Pt, which replenishes the CO poisoned Pt surface by providing OH species which accelerates the oxidation of CO to CO2. Here, we demonstrate PtRu nanoparticles deposited on Nitrogen-doped Carbon Nanotube (N-CNT) supports by microwave-assisted synthesis. The N-CNTs possess conically stacked graphitic nanostructured side walls, which can strongly anchor PtRu nanoparticles. The 3D N-CNTs support was utilized to improve the methanol mass transport at the anode side. The PtRu/N-CNTs showed enhanced CO oxidation and durability comparing to commercial PtRu/C. A DMFC prototype (5 cm2 MEA) fabricated with PtRu/N-CNTs anode, showed a power density of 102 mW/cm2 with < 4 mg/cm2 of catalyst loading using 1M methanol with 50 kPa backpressure at 90°C and maintained nearly the same power density as the methanol concentration was increased to 3M. The prototype maintained good performance up to 8M methanol.
Fabrication and Evaluation of an Anode-Supported Honeycomb SOFC with Built-in Catalytic Partial Oxidation Micro-Reformer
Authors: Higa Tasuku , Nakajima Hironori
Published: December 2020

Honeycomb solid oxide fuel cells (SOFCs) can achieve high power density with improved thermo-mechanical durability at high temperatures [1]. In this study, a compact SOFC with catalytic partial oxidation (CPOX) reforming catalyst [2, 3] embedded in the flow channels of the porous honeycomb anode support was fabricated and evaluated. I-V measurements and gas chromatography analyses for the outlet gas were carried out while methane/air mixture gas was fed as fuel. The gas chromatograph detected hydrogen in the reformed gas. Temperature distribution in the cell was also measured.

Acknowledgments

The authors are indebted to Professor Kohei Ito of Kyushu University for valuable discussions.

References

H. Nakajima, S. Murakami, S. Ikeda, and T. Kitahara, Heat and Mass Transfer, 54, 2545 (2018).

A. J. Santis-Alvarez, M. Nabavi, B. Jiang, T. Maeder, P. Muralt, and D. Poulikakos, Chemical Engineering Science 84, 469 (2012).

W. Matsunaka, H. Nakajima, A. J. Santis-Alvarez, D. Poulikakos, and K. Ito, The Proceedings of Conference of Kyushu Branch, The Japan Society of Mechanical Engineers, 71, F21, 2018.
Niobium-Zirconium Oxynitride Nanotube Arrays Forphotoelectrochemical Water Splitting
Authors: E. Salem Kholoud , Khaled Abdelrahman M. Mokhtar , Abdelhafiz Ali , K. Allam Nageh
Published: December 2020

We report on the first fabrication of vertically oriented niobium-zirconium oxynitride nanotube arrays and their use

as an attractive and robust material for visible-light-driven water oxidation. These nanotube arrays with an average diameter of ∼120

nm and very short length ∼90 nm were synthesized via one-step anodization of Nb-Zr alloy sheet in NH4F-containing electrolytes.

Ammonolysis of the nanotubes resulted in narrowing the bandgap energy from 3.23 to ∼2.67 eV. The Nb-Zr oxynitride nanotube

arrays showed approximately an enhancement of about 1900% over that reported for thin film electrodes made of niobium

oxynitride and 3700% greater than that recorded for nitrogen-doped mesoporous Nb2O5. Mott-Schottky and the valence band XPS

analyses revealed the favorable band positions of the fabricated oxynitride nanotubes with respect to the water redox potentials with

very high charge carriers density. The photocurrent transient measurements revealed the remarkable stability of the fabricated

oxynitride nanotubes.
Development of PPO-SEBS Anion Exchange Membrane with Robust Mechanical Properties and Alkaline Stability
Authors: Kim Tae-Hyun , Sung Seounghwa
Published: December 2020

The anion exchange membrane fuel cell is being studied as an alternative for the cation exchange membrane fuel cell. Since the anion exchange membrane is one of the main components of an anion exchange membrane fuel cell, it is important to develop an anion exchange membrane having high ion conductivity, good mechanical properties, and stability under alkaline conditions.

For this, this study attempted to develop AEMs with high physicochemical stability and excellent cell performance by preparing a crosslinked membrane using two polymers of PPO having high strength and SEBS having high elasticity among commercially available polymers. We observed changes in physical and chemical properties by changing the crosslinking density of the two polymers.
Oxygen Reduction Reaction Activity of Nanocolumnar Pt Thin Film Electrocatalyst Deposited on Carbon Support By High Pressure Sputtering
Authors: Basurrah Assem Omar , Ergul Busra , Yang Zhiwei , Hariharalakshmanan Ranjitha , Karabacak Tansel
Published: December 2020

Proton-exchange membrane fuel cell (PEMFC) is one of the most important sources of clean energy especially for automotive applications, which currently utilizes platinum nanoparticles dispersed on carbon (Pt/C) as a catalyst. However, the catalyst activity and durability need to be improved and the cost of the fuel cell need to be reduced for successful commercialization. Extensive research has been done to improve the catalyst activity and durability, reduce the amount of platinum used and reduce its manufacturing cost. Continuous thin film layer approach is a promising candidate for non-conventional catalysts to address these challenges. For this purpose, nanocolumnar Pt thin film (Pt-TF) layers supported on carbon was fabricated by high pressure sputtering (HIPS) and investigated as oxygen reduction reaction (ORR) electrocatalysts for PEMFCs. HIPS is a simple physical vapor deposition method that is scalable and easily applicable to industrial sputter deposition systems, in which atoms come to the substrate surface with oblique angles and form columnar structures. Different Pt-TF/C weight ratios ranging from 5% to 20% and Pt:Ni (1:3) TF/C were studied. Weight loading was controlled by changing the sputter deposition time. X-ray diffraction analysis revealed the existence of Pt and formation of the Pt:Ni alloy on carbon support. Electrochemical characterization of the carbon-supported Pt-TF samples was conducted by cyclic voltammetry and rotating disk electrode measurements in an aqueous perchloric acid electrolyte. The electrochemically active surface area, mass activity and specific activity of the Pt-TF/C samples were found to be increasing as the Pt-TF/C ratio was increased.