bluuebunny/crossref_metadata_2025 huggingface dataset:
Invited Presentation: Ionic Liquid-Based Lithium/oxygen Battery
Authors: Arbizzani Catia , Monaco Simone , Soavi Francesca , Mastragostino Marina
Published: February 2020

In the last few years, much research effort is being focused on rechargeable lithium–air (O2) batteries which feature a theoretical specific energy comparable to that of gasoline. While these cutting-edge batteries are at their early stage of development with many challenges to be overcome, they are the most promising candidates to power electric vehicles with long driving range. In the frame of the European LABOHR Project we are investigating the use of hydrophobic ionic liquid (IL)-based electrolytes in these batteries. Basic studies of the oxygen redox reaction in N-butyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide at home-made catalyst-free porous carbon electrode demonstrated that O2mass transport in IL becomes crucial at the fastest battery discharge rates, which are of interest for automotive applications. The study also demonstrated that it is possible to overcome this limitation by new flow-cell designs, and the main achievements are reported and discussed.

Acknowledgement

Work funded by the European Commission in the 7th Framework Programme FP7-2010-GC-ELECTROCHEMICAL STORAGE, under contract no. 265971 “Lithium-Air Batteries with split Oxygen Harvesting and Redox processes” (LABOHR). All the partners of the LABOHR Project are acknowledged for the fruitful discussions on Li/O2 batteries with ionic liquids.

References

[1] www.labohr.eu

[2] S. Monaco, A. M. Arangio, F. Soavi, M. Mastragostino, E. Paillard, S. Passerini, Electrochimica Acta 83 (2012) 94–104.

[3] F. Soavi, S. Monaco, M. Mastragostino, Journal of Power Sources 224 (2013) 115 – 119.

[4] S. Monaco, F. Soavi, M. Mastragostino, J. Phys. Chem. Lett. 4 (2013) 1379−1382.
Invited Presentation: Air Batteries with Ionic Liquid Electrolytes: The Abile Project
Authors: Bresser Dominic , Elia Giuseppe Antonio , Hassoun Jusef , Kwak Won Jin , Lamp Peter , Mueller Franziska , Nuernberger Simon , Oberhumer Philipp , Paschos Odysseas , Passerini Stefano , Reiter Jakub , Scrosati Bruno , Sun Yang-Kook , Tsiouvaras Nikolaos
Published: February 2020

Electrification has been a major focus of BMW and large efforts have been initiated in order to investigate technologies of high potential to be integrated in future electric vehicles. Metal-air and particularly lithium-air batteries [1] are one of the possible solutions that may substantially enhance the electric drive range. The main challenges in Li-air batteries are related to the stability of the electrolyte and safety of the negative electrode. BMW, together with three scientific teams initiated a project focusing on the use of ionic liquids and alternative anodes as potential components for Li-air batteries.

Due to their excellent electrochemical and chemical properties, onium-based ionic liquids [2] were chosen as the first candidates. The presentation will describe the electrochemical behaviour of a Li-air cell comprising such ionic liquid-based electrolytes. The results prove the concept that the chosen ionic liquid may assure the proper lithium-oxygen cell operation and electrochemical stability during cycling.

In this presentation work towards system safety improvement will be also shown [3]. In this field, alternatives to the lithium metal anode were investigated. The latter include: i) tin-carbon composite, ii) carbon-coated Zn1-xFexO [4], iii) SiOx-carbon and SiOx-silicon materials. Electrochemical tests have shown reversible behaviour of all materials both in conventional organic electrolytes as well as in electrolytes based on ionic liquids.

References:

Girishkumar G., McCloskey B., Luntz A.C., Wanson S., Wilcke W.: Lithium-air battery: Promise and Challenges. J. Phys. Chem. Lett., 2010, 1 (14), p. 2193-2203.

Armand M., Endres F., MacFarlane D.R., Ohno H., Scrosati B.: Ionic-liquid materials for the Electrochemical Challenges. Nature Mat., 2009, 8 (8), p. 621-629.

Hassoun J., Jung H.G., Lee D.J., Park J.B., Amine K., Sun Y.K., Scrosati B.: A Metal-Free, Lithium-Ion Oxygen Battery: A Step Forward to Safety in Lithium-Air Batteries. Nano Letters, 2012, 12, p. 5775-5779.

Bresser D., Mueller F., Fiedler M., Krueger S., Kloepsch R., Baither D., Winter M., Paillard E., Passerini S.: Transition-Metal-Doped Zinc Oxide Nanoparticles as a New Lithium-Ion Anode Material. Chemistry of Materials, 2013, 25 (24), p. 4977-4985.
Invited Presentation: The Roles of Graphene in Lithium Batteries
Authors: Ren Wencai , Cheng Hui-Ming
Published: February 2020

Graphene attracts increasing interest in lithium storage because of the significant improvement in electrochemical performance of graphene-based electrode materials. Synergistic effects between graphene and electrode materials and the beneficial roles of graphene in composite electrodes are found. It is demonstrated that, when the composites are used as electrode materials for lithium storage, compared to their individual constituents, graphene composites with unique structures such as anchoring, wrapping, encapsulating, sandwiching, buffering, layering and mixing have a significant improvement in their electrochemical properties such as high capacity, high rate capability and excellent cycling stability. The roles of graphene are found mainly to form a conductive network, increase ion conductivity, anchor and trap electrode materials.
Anodic Tin Oxide Thin Films with Nano-Channeled Structure for Lithium Battery Anode
Authors: Kim Eun-Ji , Shin Heon-Cheol
Published: February 2020

One-dimensional (1-D) nano-channeled structure has attracted attention as electrode design for the high performance electrochemical devices. This is mainly because its 1-D nano porous structure would allow for the fast ionic transport through it and rapid interfacial reactions. One of the conventional preparation methods of 1-D nano-channeled structure is anodic oxidation. Since the first introduction of anodic aluminum oxide (AAO), different anodic metal oxides with 1-D structure have been reported for the past few decades.

Among the various 1-D metallic oxides reported in the literature, tin oxide might be utilized for various applications, such as catalysis, gas sensing, and electrochemical energy storage. In particular, when the nano-channeled tin oxide is used as the anode of the lithium battery, both of the lithia(Li2O) network and nano-channeled structure accommodate the volume change of the tin-lithium phase during the charging/discharging cycles. Although there are some attempts to use the anodic tin oxide thin film as the electrode material for lithium battery, the active material on the substrate was not pure tin oxide but tin - tin oxide bilayer. Since the tin layer underneath anodic tin oxide undergoes a significant reaction-induced volume change, 1-D structure of bilayer collapses during the cycling,

In this work, pure anodic tin oxide with well-defined 1-D structure was prepared for the use as the anode for rechargeable lithium battery. Anodic tin oxides with different pore sizes and wall thicknesses were fabricated under various anodizing conditions and their electrochemical properties were characterized by cyclic voltammetry and charge-discharge experiment.

In this presentation, cycling stability and rate capability of anodic tin oxides with different porous structures will be presented. Moreover, the feasibility of creating 1-D tin-based anodic oxide composite will be discussed for the further improvement of cycling stability.
Na2+XTi6O13 As Potential Negative Electrode Material for Na-Ion Batteries
Authors: Shen Kun , Wagemaker Marnix
Published: February 2020

Na-ion as a charge carrier is one of the most promising alternatives for Li-ion storage due to its high abundance and low cost. Here we show that the reversible capacity of the recently reported layered Na2Ti6O13 negative electrode material can be enhanced from 49.5 mAh/g (Na2+1Ti6O13) to 196 mAh/g (Na2+4Ti6O13) when the cut-off voltage is lowered from 0.3 V to 0 V. However, the lower cutoff voltage leads to a decrease in reversible capacity, most likely due to electrolyte decomposition. In-situ X-ray diffraction experiments in combination with DFT calculations reveal the structural changes, including the Na-ion positions, in Na2+xTi6O13. Up to Na2+2Ti6O13 a solid solution mechanism is demonstrated with small structural changes. Both DFT and X-ray diffraction indicate that Na2+2Ti6O13 is the upper limit of the Na-ion storage in the bulk of the material. The 196 mAh/g (Na2+4Ti6O13) capacity achieved at 0 V is suggested to be the consequence of a surface storage reaction. The combination of the large capacity and a solid solution mechanism with small structural changes make this material of potential interest for the use as negative electrode in Na-ion batteries.
High Voltage Pyrophosphate Cathodes for Li- and Na-Ion Batteries: Atomic-Scale Insights into Defects and Diffusion
Authors: Islam M. Saiful , Clark John , Barpanda Prabeer , Yamada Atsuo
Published: February 2020

Major advances in rechargeable batteries for electronics, electric vehicles and grid storage requires the development of new materials. Recently, it has been proposed that the pyrophosphate framework may provide a new platform for important electrode research. Li2FeP2O7 displays reversible reaction at 3.5 V vs Li/Li+ without nanosizing or carbon coating, which is the highest voltage for any Fe-based phosphate cathode [1]. There is growing interest in sodium-ion batteries largely due to the natural abundance of sodium and cost issues for grid-storage. The sodium pyrophosphate, Na2FeP2O7, has been found to be electrochemically active (3V vs Na/Na+) [2], which is the first pyrophosphate-type of cathode for Na-ion batteries.

This presentation highlights recent studies of both Li2FeP2O7 and Na2FeP2O7 using atomistic simulation techniques [3] to provide detailed insights into defect, dopant and ion migration properties relevant to their electrochemical behaviour [4]. Li/Fe and Na/Fe antisites were found to be the most favourable intrinsic defects suggesting significant disorder, which would be sensitive to synthesis conditions. In contrast to 1D diffusion in LiFePO4, fast Li+ transport in Li2FeP2O7 is predicted to be through a 2D network. Interestingly, the Na2FeP2O7 structure appears to support quasi-3D Na+ diffusion. Hence, a significant result is that alkali-ion diffusion within this framework is found to be either 2D or 3D with low energy barriers, which are important for good rates of charge/discharge.

References

[1] S. Nishimura, M. Nakamura, R. Natsui, A. Yamada, J. Am. Chem. Soc.
2010, 132, 13596.

[2] P. Barpanda, T. Ye, S. Nishimura, S.C. Chung, Y. Yamada, M. Okubo, H.S. Zhou, A. Yamada, Electrochem. Commun.
2012, 24, 116.

[3] M.S. Islam and C.A.J. Fisher, Chem. Soc. Rev.
2014, 43, 185.

[4] J.M. Clark, S.-I. Nishimura, A. Yamada, M.S. Islam, Angew. Chem. Int. Ed.
2012, 51, 13149.
Understanding the Redox Reaction Mechanism of Li2CoPO4f Cathode Material for Achieving Two Lithium Intercalation
Authors: An Jae Youn , Palanichamy Sennu , Lee Sol Nip , Samuthira Pandian Amaresh , Lee Yun Sung
Published: February 2020

Lithium ion batteries have attracted considerable attention as important energy storage and conversion systems for applications including electric vehicles (EVs) and hybrid electric vehicles (HEVs), owing to their high energy and power densities, as well as a long cycle life. Recently, lithium transition metal phosphates, such as LiFePO4, LiMnPO4, and Li3V2(PO4)3, have been considered as potential cathode materials for lithium ion batteries. It is well known that the phosphates display much better electrochemical and thermal stability compared to conventional lithium metal oxides [1]. However, recently, fluorophosphates are being developed as advanced cathode materials display higher operating potential, corresponding to the redox reaction of transition metal, when compared to the respective metal oxides and phosphates [2]. In addition, the highly electronegative fluoride ion helps to improve the cycle stability, which fluorophosphates make attractive materials for high energy batteries.

Our current work is focused on maximizing the deliverable discharge capacity of Li2CoPO4F cathode material and to reach theoretical capacity by achieving more than one electron intercalation. The redox couple Co2+/3+ and Co3+/4+ was closely followed during galvanostatic charge-discharge test by x-ray photoemission spectroscopy and x-ray diffraction (XRD) analysis. It was found that the incomplete reduction of cobalt ions during discharge initiated the irreversible capacity loss rather than the electrolyte decomposition being solely responsible. A novel approach was carried out to activate the transition metal ions which resulted in a discharge capacity as high as 230 mAh g-1 at a current rate of 20 mA g-1 for Li/Li2CoPO4F cell. A long plateau at 4.8 V has been observed in the charge cycle with an additional voltage plateau at ~5.0 V, which can be attributed to the two lithium intercalation reaction and has been validated using cyclic voltammetry studies. The detrimental cycle stability observed [3] in Li2CoPO4F has been replaced with a stable cycle performance of > 90 % capacity retention as shown in figure 1. A quasi single phase reaction was confirmed using gravimetric intermittent titration technique in addition to the results from ex-situXRD studies. A discussion based on the obtained results will be presented in detail.

References:

[1] S.K. Martha, J. Grinblat, O. Haik, E. Zinigrad, T. Drezen, J.H. Miners, I. Exnar, A. Kay, B. Markovsky, D. Aurbach, Angew. Chem. Int. Ed.48 (2009) 8559–8563.

[2] A. Kraytsberg, Y. E. Eli, Adv. Energy Mater.2 (2012) 922–939.

[3] X. Wu, Z. Gong, S. Tan, Y. Yang, J. Power Sources 220 (2012) 122–129.
Crystal Structure and Electrochemistry of Na2-XLixFePO4f (0≤x≤1) New Cathode Materials for Li- and Na-Ion Batteries
Authors: Kosova Nina V. , Podugolnikov Vladislav R. , Bobrikov Ivan A. , Balagurov Anatoly M.
Published: February 2020

Sodium-based cathode materials are interested both for sodium-ion and lithium-ion batteries application. In 2007, Ellis et al
. [1] synthesized a new sodium-based flourophosphate Na2FePO4F. This material operates at 3.3 V and has two-dimensional (2D) pathways for intercalation/deintercalation of alkaline ions and a single-phase (solid solution) mechanism of Li (de)intercalation.

In the present study, Na2-xLixFePO4F with 0≤x≤1 were prepared by mechanochemically assisted solid state synthesis. Na2FePO4F was synthesized via two-step approach including a covalent precursor formation (NaFePO4) and incorporation of ionic NaF into its framework. Both steps consist of preliminary mechanical activation (MA) using AGO-2 planetary mill and subsequent heat treatment in Ar flow. Na2-xLixFePO4F compositions were obtained from NaFePO4, LiFePO4, NaF and LiF with the correspondent ratio. Crystal and local structure was studied by X-ray, neutron diffraction (IBR-2 reactor of JINR, Dubna) using Rietveld refinement (Fig. 1); FTIR and Mössbauer spectroscopy. Phase transformations under heating and cooling of the NaFePO4+NaF activated mixture were investigated by in situ XRD, using a HTK 1200N temperature-controlled X-ray chamber. Particle size and morphology were studied by SEM and TEM. The samples were cycled in Swagelok-type half-cells with Li anode and LiPF6-based electrolyte at 2.0-4.2 V range and 0.1C-10C cycling rates. GITT method was applied for the evaluation of D
Li.

It has been shown that poor-crystalline Na2FePO4F was formed directly at the stage of MA. The completion of the synthesis and crystallization of the final product with Pbcn space group and average particle size of about 100 nm occur upon the subsequent heating of the activated mixture to 600°C. Refined cell parameters, presented in Table 1, well correlate with the literature data [1]. On contrast, the structure of as prepared Na2-xLixFePO4F (0.5≤x≤1.0) is well described in Pnma space group. Mössbauer spectra are fitted by one doublet indicating that all Fe ions are in 2+ state and octahedral coordination.

On galvanostatic charge-discharge curves, a solid solution-like sloping voltage profile was observed for all samples. When cycled with Li anode, Na/Li exchange in Na2FePO4F cathode with the formation of NaLiFePO4F was completed after the 4th cycle. The structure of the product was maintained (S.g. Pbcn), while its lattice parameters decrease. Discharge capacity was 115, 110 and 55 mAh×g-1 for Na2FePO4F, Na1.5Li0.5FePO4F and NaLiFePO4F, respectively (Fig. 2). The determined Li+ diffusion coefficient D
Li in NaLiFePO4F, prepared by electrochemical Na/Li exchange from Na2FePO4F, was 10-15 cm2×s-1 (Fig. 3), while it was only 10-17 cm2×s-1 for NaLiFePO4F and Na1.5Li0.5-xFePO4F (S.g. Pnma) prepared by solid state synthesis.

[1] B. Ellis, W.R.M. Makahnouk, Y. Makimura, K. Toghill, L.F. Nazar // Nat. Mater. 6(2007) 749–753.
Quenching Thermal-Runaway in Lithium Ion Battery By Hyperbranch Cathode Additives
Authors: Chu Po-Jen , Chuang Chih-Yuan
Published: February 2020

One major issue in lithium ion battery is the safety where numerous explosion events created public concern and prevented it from wider application to transportation sector. The safety issue is primarily originated from the use of volatile organic solvent such as,EC, PC, and DMC.etc that contains thermally decomposible lithium salts (LiPF6, LiClO4 etc.). Few approaches are explored to improve the lithium battery safety:, (a). The use of electrode materials without oxygen release (LiFePO4). (b). use of non- volatile solid-state electrolytes (ionic liquids). (c). use of non-flamable or fire retardant separator material (ceramic) (d). External electronic circuit protection, and (e)Shut down the thermal run-away by the use of additives. This paper disclosed results of a hyperbranch additive which can be thermally triggered to quench the oxyge release, block the combustion chain reaction, and accomplished successfully an active protective shut down. Furthermore, the additive forms porous protective layer (less than few nm) which hinders thick SEI formation and prevent direct electrolyte contact with the active material thus improves cycle-life. Finally, the hyperbranched layer with flexible side chain created fast lithium ion transport path across/from the active materials, and improves high rate performance. Details of the structure of the hyperbranched additives will be discussed.
Synthesis of Graphene-Supported Nano-Na3MnCO3PO4 for High Rate and High Capacity Sodium Ion Batteries
Authors: Daneshvar-Fatah Farhad , Wang Chualong , Shaw Leon
Published: February 2020

It has been predicted via ab-initio calculations that Na3MnCO3PO4 possesses a high specific capacity of 191 mAh/g, due to its potential to deliver two-electron transfer redox reactions per formula via Mn2+/Mn3+ and Mn3+/Mn4+ redox reactions (Hautier, et al. 2011). To improve battery performance for high power applications such as hybrid electric vehicles and electric grid systems, it is necessary to enhance the electronic conductivity. Graphene has been reported to be a suitable conductive substrate to grow active materials for energy storage applications owning to its superior electrical conductivity, chemical stability, high mechanical strength, high surface-to-volume ratio, and light weight. In this study, Na3MnCO3PO4, one of the most promising materials for Na-ion batteries, has been synthesized on a graphene sheet surface via hydrothermal method. The cathode material was characterized by FE-SEM, XRD, and electrochemical tests. It is shown that by having the total graphene content as low as 5.1wt%, specific capacity improves 40%. With this improvement in specific capacity, Na3MnCO3PO4 has a great potential to be a viable cathode material for Na-ion batteries.
Magnesium Sulphide As Anode Material for Lithium-Ion Batteries
Authors: Maria Joseph Helen , Fichtner Maximilian
Published: February 2020

There is a great interest for alternative high capacity, low voltage anode materials in Li ion batteries. In an attempt towards this we report the investigation of magnesium sulphide (MgS) as sustainable anode material for lithium-ion batteries. The theoretical reaction potential of MgS with lithium is 0.5 V. It has a theoretical specific capacity of 951 mAh g-1 assuming the following reaction.

MgS + 2Li   --->   Li2S + Mg

In addition, lithium can react with magnesium to form alloys of lithium by further increasing the theoretical capacity. The high capacity combined with low reaction potential makes MgS an interesting anode material for Li-ion batteries in principle. Hence we synthesized MgS-carbon nanocomposites and evaluated them as anode material for lithium-ion batteries. A possible lithiation and delithiation mechanism for MgS is proposed based on electrochemical and ex-situ XRD studies. The electrochemical reaction of MgS with lithium results in the formation of Li2S and Mg, the as-formed Mg simultaneously reacts with lithium and forms LixMg alloy further contributing to the capacity. A stable reversible capacity of 530 mAh g-1 was achieved after 100 cycles within the voltage window of 0.001 - 2.5 V (Figure 1). The compatibility of MgS anode was tested in full cell using lithium nickel manganese cobalt oxide (LNMC) and lithium iron phosphate (LFP) as cathodes.

Figure 1
Liquid-Free Lithium-Oxygen Battery
Authors: Balaish Moran , Peled Emanuel , Golodnitsky Diana , Ein-Eli Yair
Published: February 2020

Non-aqueous Li-O2 batteries are considered as most advanced power sources, albeit they are facing numerous challenges concerning almost each cell component. Herein, we diverge from the conventional and traditional liquid-based non-aqueous Li-O2 batteries to a solid polymer electrolyte (SPE) Li-O2 system, operated at a temperature higher than the melting point of the polymer electrolyte, where useful and most applicable conductivity values are easily achieved. The proposed SPE-based Li-O2 cell is compared to glyme-based Li-O2 cells through potentiodynamic and galvanostatic studies, showing higher cell discharge voltage by 80mV and most significantly, a charge voltage lower by ∼400mV. The solid state battery demonstrated a comparable discharge specific capacity to glyme-based Li-O2 cells when discharged at the same current density. The discharge products were identified as lithium peroxide by XRD analysis and FT-IR combined with quantitative 1H and qualitative 13C NMR spectroscopies identified lower molecular PEO as the main degradation products, as well as in-chain ester and formates in negligible amounts. The results shown here demonstrate that safer PEO-based Li-O2 battery is highly advantageous and can potentially replace liquid-based cells contingent upon further investigation. While safety is a prime concern in Li-metal based battery, it is of greater challenge once a viable Li-O2 battery development is being considered. A polymer-based system, which is liquid electrolyte-free, seems to be another and important step towards resolving this issue.

* Balaish, M., Peled, E., Golodnitsky, D. and Ein-Eli, Y. (2014), Liquid-Free Lithium–Oxygen Batteries. Angew. Chem. Int. Ed.. doi: 10.1002/anie.201408008
High Performance NiO and NiO/Graphene Composite Thin Film Electrode Via Electrostatic Spray Deposition for Lithium Ion Batteries
Authors: Chen Chunhui , Pedro Perdomo J. , Fernandez Melisa , Barbeito Andres , Wang Chunlei
Published: February 2020

NiO has been widely studied due to its high theoretical capacity of 718 mAh g-1 when it is used as anode material for LIBs. However, it shows poor cycling performance due to the low electrical conductivity and large volume change during charge/discharge. In the present research, NiO thin film electrode was synthesized by electrostatic spray deposition (ESD) technique and investigated as anodes for lithium ion batteries. 10% weight percent graphene nanoplates were added to form NiO/graphene nano-composite. We expect that additional graphene will provide a high conductive medium for electron transfer during the conversion reaction of NiO with lithium ions. In addition, the porous structure generated through ESD process will be benefical to buffering the volume expansion/constriction during the cycling.

The cycling of NiO electrode results show that it can deliver a reversible capacity of 708 mAh g-1 under the current density of 0.5 A g-1. The number is near the theoretical capacity of NiO which indicates the complete reaction of NiO with lithium ions. As the current density increases, the capacity gradually decreases to 80 at 5 A g-1. For the NiO/graphene composite electrode, capacity decreased from 683 to 125 mAh g-1 as the current density increased from 0.5 to 5 A g-1. Comparing these two electrodes, it shows that additional graphene is not beneficial to the capacity testing under low current densities. Whereas, it has a positive synergistic effect towards the capacity testing under high current densities. It is probably because of two reasons: one is that graphene itself has lower theoretical capacity than NiO; another one is that the porous thin film structure can satisfy the kinetics requirement of the reactions under low current densities. In addition to rate capability tests, material characterization (such as SEM, XRD, FTIR) and additional electrochemical tests (cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), etc.) were performed to evaluate the performance of such electrodes. Detailed discussion will be provided during the meeting.
Biomimetic Porphyrin Aggregation for Developing Novel Phase Change Photonic Materials
Authors: Zheng Gang
Published: February 2020

Porphyrins are aromatic, organic, light-absorbing molecules that occur abundantly in nature, especially in the form of molecular self-assemblies. Mimicking such highly efficient self-assembled systems has a vast potential in a variety of applications, from sensing, photomedicine to nanomedicine. Our recent discovery of porphysome provides a glimpse of this potential as the self-assembly of porphyrin-lipid building blocks enables intrinsic multimodal properties including photothermal/photoacoustic (intact state), photodynamic/fluorescent (disrupted state), and PET and MRI (metal chelating of porphyrin building blocks). To broaden its utility, we are looking for ways to create phase change porphysomes that could be developed into photonic molecular sensors that are capable of detecting environmental stimuli through alterations of optical absorption. Photosynthetic organisms have evolved ingenious strategies to optimize light absorption through nanoscale ordered dye aggregation. Learning from these nature’s self-assembly principles, we have recently succeeded in making the first phase change porphyrin nanoparticle, a tuneable, reversible and stimuli-responsive photoacoustic nanoswitch based on the change in aggregation-induced large absorption shift. Using this new photonic material, we non-invasively determined a localized temperature change in vivo, relevant for monitoring thermal therapies of solid tumors. Similar strategies may be applied alongside photoacoustic imaging, to detect other stimuli such as pH and enzymatic activity.
Electrochemical Properties of a New Class of Europium Sandwich Triple-Decker Complexes with Corrole and Phthalocyanine Macrocycles
Authors: Lu Guifen , Yan Sen , Shi Mengying , Li Jing , Ou Zhongping , Zhu Weihua , Kadish Karl M.
Published: February 2020

The electrochemical properties of a new class of sandwich (phthalocyaninato)(corrolato) europium triple-decker complexes were synthesized and characterized by cyclic voltammetry in CH2Cl2 containing 0.1 M tetrabutylammonium perchlorate (TBAP) as supporting electrolyte. Two of the compounds described in the current paper are shown in the figure, and represented by HEu2[Pc(R)8]2[Cor(ClPh)3], where R = OC5H11 or OC8H17, Pc represents the dianion of phthalocyanine and Cor represents the trianion of corrole. Both triple-decker complexes exhibit five reversible oxidations and three reversible reductions, all of which are attributed to ligand-based redox processes. The half-wave potentials for the first oxidation and first and second reduction of the two europium triple-deckers are close to E
1/2 values for the double-decker species Eu[Pc(OC8H17)8]2, while half-wave potentials for the second to fifth oxidations are close to E
1/2 values for the triple-decker Eu2[Pc][Pc(OC8H17)8]2. The synthesis and electrochemical properties of the new compounds will be described.

Acknowledgment: This work was supported by the Natural Science Foundation of China (No. 21001054, 21071067) and the Robert A. Welch Foundation (K.M.K., Grant E-680).

Figure 1
Hexabenzocoronene-Porphyrin Conjugates
Authors: Jux Norbert , Lungerich Dominik
Published: February 2020

Hexabenzocoronene (HBC) is a very interesting building block in terms of structural and electronic properties.[1] We have recently started to look into conjugates with the HBC moiety directly linked to a meso-position of the porphyrin.

Here, we wish to report on the synthesis, characterization, and properties of some of these novel systems.[2,3]

 

References

[1]        S. Ito, P. T. Herwig, T. Böhme, J. P. Rabe, W. Rettig, K. Müllen, J. Am. Chem. Soc. 2000, 122, 7698 – 7706; b) J.Wu, M. D. Watson, N. Tchebotareva, Z. Wang, K. Müllen, J. Org. Chem. 2004, 69, 8194 – 8204.

[2]        J. M. Englert, J. Malig, V. A. Zamolo, A. Hirsch, N. Jux, Chem. Commun. 2013, 49, 4827 – 4829.

[3]        D. Lungerich, J. F. Hitzenberger, M. Marcia, F. Hampel, T. Drewello, N. Jux, Angew. Chem. Int. Ed..
2014,
53, 12231-12235.

Figure 1
Electrochemically Controlled Multistability of Ultrathin Films of Double-Decker Lanthanides Phthalocyanines
Authors: Gorbunova Yulia G. , Selektor Sofiya L. , Shokurov Alexander V. , Arslanov Vladimir V. , Tsivadze Aslan Yu.
Published: February 2020

Molecular-scale systems that exhibit intramolecular electron transfer (IET) induced by various external stimuli occupy a special place among the systems whose behaviour is determined by charge transfer processes. Such redox-isomeric materials are indeed promising for applications in the development of nanoscale information storage devices. Complexes in which both metal and ligand are redox-active are target objects for the study of redox isomerism phenomenon (reversible intramolecular metal−ligand electron transfer). From this standpoint, tetrapyrrole complexes of metals with variable oxidation states are one of the most promising compounds. Lanthanides phthalocyaninates proved to be very promising objects for the development of “molecular switches” and memory devices.

Herein, we report on the electrochemical properties of Langmuir-Blodgett films of series of lanthanides complexes with bis-tetra-15-crown-5-phthalocyanines1,2. A previously unknown phenomenon of orientation-induced redox isomerism in a Langmuir monolayer is revealed in the case of cerium bis-[tetra-(15-crown-5)-phthalocyaninate] – (Ce[(15C5)4Pc]2)3,4 (Fig.1). The mechanism of genuine redox isomerism was confirmed by the results of in-situUV-Vis spectral measurements performed on monolayers and Langmuir-Blodgett films, AFM, and XPS studies of Langmuir-Blodgett films transferred at different surface pressures. The understanding of this reversible IET mechanism is especially important due to possible applications of such redox-isomeric systems in the development of nanoscale multibit information storage devices.

1.         Selector, S. L.; Arslanov, V. V.; Gorbunova, Y. G.; Raitman, O. A.; Sheinina, L. S.; Birin, K. P.; Tsivadze, A. Y. Journal of Porphyrins and Phthalocyanines
2008, 12, 1154.

2.         Selector, S. L.; Shokurov, A. V; Arslanov, V. V; Gorbunova, Y. G.; Raitman, O. A.; Isakova, A. A.; Birin, K. P.; Tsivadze, A. Y. Rus. J. of Electrochemistry
2012, 48, 218.

3.         Selektor, S. L.; Shokurov, A. V.; Raitman, O. A.; Sheinina, L. S.; Arslanov, V. V.; Birin, K. P.; Gorbunova, Y. G.; Tsivadze, A. Y. Colloid J.
2012, 74, 334.

4.         Selektor, S.L.; Shokurov, A.V.; Arslanov, V.V.; Gorbunova, Y.G.; Birin, K.P.; Raitman, O.A.; Morote, F.; Cohen-Bouhacina, T.; Grauby-Heywang, Ch.; Tsivadze, A.Yu. J. Phys.
Chem. C
.,    2014, 118, 4250.

Figure 1
(Energy Technology Division Graduate Student Award) All-Graphene Energy Storage Device for High Energy and Power Density
Authors: Kim Haegyeom , Lim Hee-Dae , Hong Jihyun , Kang Kisuk
Published: February 2020

The prime importance in the energy storage field is to develop a new system that can combine high energy and power density. While lithium-ion batteries (LIBs) have become scientifically and commercially important because of their high energy densities, their power densities are not sufficient for emerging large-scale applications. Supercapacitors, on the other hand, are capable of delivering very high power due to their intrinsically fast surface-reaction mechanism, but they fail to meet high energy density requirements.

This presentation proposes a new type of battery that adopts the fast surface reaction mechanism mimicking the supercapacitor without sacrificing energy density: an all-graphene energy storage device. The key advantages of an all-graphene energy storage device are that (i) both electrodes (a functionalized graphene cathode and a reduced graphene anode) exhibit fast surface reactions instead of intercalation while maintaining high energy density, and (ii) simple chemical modification of graphene yields either the anode or the cathode in a one-pot synthesis. Combined with controlled porous morphology and high electrical conductivity of graphene, the all-graphene energy storage device was capable of delivering a high energy of 195 Wh/kgtotal electrode, which is comparable to the energy density of conventional LIBs. The newly developed all-graphene energy storage device also retains 8.5 Wh/kgtotal electrode (energy) and 3,300 W/kgtotal electrode (power) at charge/discharge rates of just a few seconds. This energy and power performance perfectly spans the region that conventional LIBs and supercapacitors cannot reach. The performance and operating mechanism of an all-graphene energy storage device resemble those of both supercapacitors and batteries, blurring the conventional distinction between the two. This work sheds new light on the development of advanced energy-storage devices that bridge the performance gap between LIBs and supercapacitors.

Presenting author: H. Kim

E-mail: kimhaegyeom1@gmail.com

Corresponding author: K. Kang

E-mail: matlgen1@snu.ac.kr
3D Zinc Sponge Anodes: Towards Next-Generation Ni-Zn Batteries
Authors: Parker Joseph F. , Pala Irina R. , Chervin Christopher N. , Nelson Eric S. , Long Jeffrey W. , Rolison Debra R.
Published: February 2020

Zinc-based batteries (e.g., Zn–air, Ag–Zn, Ni–Zn) are endowed with high specific energy (up to 400 Wh kg–1), high specific power, nonflammable alkaline electrolytes, and an earth-abundance of active materials. The advantages of zinc-based batteries make them the ideal energy storage solution to address the pitfalls of its battery-chemistry competitors—from the toxicity and low specific energy of Pb-acid to the flammability of Li-ion. The historical failure of zinc to be recognized as a worthy competitor to other technologies lies in its bedeviled non-rechargeability and modest zinc utilization (typically <60% of theoretical discharge capacity), especially when constructed as an ad-hoc powder composited electrode. Traditionally, when Zn is oxidized to Zn2+ during discharge, it forms zincate complexes (e.g. Zn(OH)4
2–

(aq)
) that are soluble in the alkaline electrolyte. These mobile Zn-carriers can diffuse beyond the site of generation but eventually supersaturate and precipitate as poorly conductive ZnO. The reverse step (charging) is initiated by re-dissolution of the ZnO to zincate prior to reduction back to Zn0. Multiple iterations of the above processes eventually lead to electronic isolation of portions of the electrode, hotspots of high-current density, and growth of short-inducing dendrites. To circumvent these problems, we design and fabricate 3D zinc "sponge" anodes that are monolithic and comprise an interpenetrating, co-continuous network of solid and void [1]. The electrode—now wired in 3D—enables low cell resistances throughout discharge that allow access to >90% of the zinc [2]. The morphology of the discharged sponges reveals a uniform deposition of ZnO on the inner walls of the sponge electrode, providing a core–shell 3D structure with an 3D-wired inner Zn metallic core that is ideal for electrochemical recharge with 100% capacity retention. We have identified the Ni–Zn battery system, with its established and rechargeable NiOOH cathode, as a prime candidate to begin implementing 3D-Zn sponge electrodes towards next-generation alternatives to Pb-acid, Ni–Cd, Ni–MH, and Li-ion batteries. We present the design and fabrication of 3D-Zn sponge anodes and their cycling performance in Ni–Zn full cells, with specific emphasis on cell fabrication, electrolyte composition, and post-mortem analysis.

The information, data, or work presented herein was funded in part by the Office of Naval Research and by the Advanced Research Projects Agency–Energy (ARPA–E), U.S. Department of Energy, under Award Number DE-AR-0000391; the work has been Approved for Public Release, Distribution Unlimited.

[1] J.F. Parker, C.N. Chervin, E.S. Nelson, J.W. Long, D.R. Rolison, Energy Environ. Sci.
7 (2014) 1117–1124.

[2] J.F. Parker, E.S. Nelson, M.D. Wattendorf, C.N. Chervin, J.W. Long, D.R. Rolison, ACS Appl. Mater. Interfaces, in the press.
Lithium Overpotential and Dendrite Formation
Authors: Heine Jennifer , Bieker Peter , Winter Martin
Published: February 2020

Lithium metal has a higher theoretical capacity compared to graphite, which is the most commonly used anode material in a lithium ion battery (LIB).[1] Nevertheless, secondary lithium metal batteries have plenty of challenges to overcome, before they could replace the well established LIBs. One main challenge of these batteries is the lithium dendrite formation during cycling. In the presence of an appropriate organic electrolyte, lithium is kinetically stable against corrosion due to the formation of a solid electrolyte interphase (SEI).[2] If the SEI is locally different in morphology and composition, the current density distribution on the lithium electrode during charging can be inhomogeneous. This leads to an inhomogeneous lithium plating process and results in a needle-like deposition, which is frequently called dendritic lithium deposition.[3] Figure 1 depicts needle-like lithium deposition on the lithium electrode after cycling. During cycling, dendrites can grow from the anode to the cathode and can cause a short circuit or a thermal runaway.

Different types of lithium deposition morphologies are known: needle-like, mossy and granular lithium.[4-5] The needle-like lithium (Figure 1b), with its high surface area, has most detrimental impact on cycling and safety performance of lithium metal cells. A novel method to monitor the changes of the surface morphology during cycling is the continuous observation of the development of lithium overpotential during cycling (Figure 1a).

In this work, we will explain how the overpotential occurs and how the lithium overpotentials correlate with the change of the surface structure. Furthermore, it is demonstrated that by increasing the surface area of the lithium metal electrodes and, in parallel, using a highly concentrated electrolyte, the formation of dendritic lithium can be reduced.

References

[1] von Sacken, U.; Nodwell, E.; Sundher, A.; Dahn, J. R., J. Power Sources
1995,
54(2), 240-245.

[2] Winter, M., Zeitschrift für Physikalische Chemie
2009,
223(10-11), 1395-1406.

[3] Aurbach, D.; Zinigrad, E.; Cohen, Y.; Teller, H., Solid State Ionics
2002,
148(3–4), 405-416.

[4] Gireaud, L.; Grugeon, S.; Laruelle, S.; Yrieix, B.; Tarascon, J. M., Electrochem. Commun.
2006,
8(10), 1639-1649.

[5] Sano, H.; Sakaebe, H.; Matsumoto, H., J. Power Sources
2011,
196(16), 6663-6669.

Figure 1 a) Overpotential of lithium during cycling, b) needle-like dendrites.

Figure 1
3,7-Bis(trifluoromethyl)-N-Ethylphenothiazine: A Highly Soluble, Highly Stable Redox Shuttle and Electro-Active Material for Non-Aqueous Redox Flow Batteries
Authors: Odom Susan A , Ergun Selin , Elliott Corrine F , Kaur Aman Preet , Holubowitch Nick
Published: February 2020

3,7-Bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) is one of several derivatives of phenothiazine prepared in our laboratory for evaluation as redox shuttles for overcharge protection in lithium-ion batteries.  We varied alkyl substituents at the N position and incorporated electron-withdrawing substituents at the 3 and 7 positions. Derivatives with ethyl and iso-propyl groups at the N position were the most stable, and those with chloro and trifluoromethyl substituents were the most robust in overcharging lithium-ion batteries. BCF3EPT showed the highest rate performance when dissolved at 0.5 to 1.5 M in 1.2 M LiPF6 in EC/EMC in graphite/LFP coin cells. At 0.08 M BCF3EPT, batteries lasted over one year in overcharge at a charging rate of C/10. When compared to dimoethoxybenzene-based redox shuttles, the radical cation of BCF3EPT – generated by chemical oxidation with tris(2,4-dibromophenyl)aminium hexachloroantimonate – was more stable in battery electrolyte. The stability of the radical cation form of redox shuttles is critical to overcharge protection and limited effects of the redox shuttle on SEI formation, so the stability of the radical cation of BCF3EPT may explain its extended performance in side-by-side overcharging experiments. In addition to overcharge protection studies, we also studied BCF3EPT as an electron-donating electro-active material in non-aqueous redox flow batteries including one example in which BCF3EPT and trimethylquinoxilane (TMeQ) were incorporated into 1 M LiBF4 in PC and tested in a stationary coin cell following a setup used by Brushett’s group, testing concentrations up to 0.4 M of both species, the anolyte being the limiting factor in high concentration batteries. Lastly, we have focused on the scale-up of BCF3EPT, which we prepare in three steps from commercially available phenothiazine. So far the first and second transformations have yields of more than 95%, and the last step - the trifluoromethylation – can be conducted in over 90% yield.

Figure 1
Hollow Carbon Nanosphere/Germanium Nanoparticle Composite Li-Ion Anode
Authors: Banek Nathan A , Hays Kevin Alan , Wagner Michael J
Published: February 2020

Since their introduction, lithium ion batteries have become ubiquitous for powering portable electronic devices. However, the charging rate of graphite (by far the most common anode material) is relatively slow due to long lithium diffusion pathlengths. Highly graphitic hollow carbon nanospheres (HCNS) have a tremendous advantage over micron-sized graphite particles as the diffusion path length is on the nanoscale, 3 orders of magnitude shorter than graphite’s, facilitating rapid charging within a few minutes, rather than many hours. In addition, HCNS anodes cycle stably in inexpensive low melting point electrolytes, cycling with excellent capacity retention and high rate at temperatures as low as -50 ˚C.  Unfortunately, HCNS anodes have lower specific capacity compared to those made with graphite (~220 mAh/g vs. 372 mAh/g).(1)  However, the high surface area, good electrical conductivity and excellent electrochemical stability of HCNS make it a promising support material for other high capacity lithium alloying materials, suggesting the possibility of significantly higher specific capacities, much better low temperature performance and charging rates than graphite-based anodes. Here we present our studies to date on the incorporation of germanium metal, second only to Si in gravimetric capacity as a Li alloying material (1385 mAh/g) and nearly equal to it in volumetric capacity (7372 mAh/mL), into HCNS anodes.

Syntheses were performed at room temperature by solution phase reduction of germanium precursors in the presence of the HCNS to produce conductive composites of Ge nanoparticles supported on HCNS. When cycling from 1.5 to 0.02 V vs. Li, a stable capacity of ~600 mAh/g electrode ( ~1200 mAh/g Ge) was obtained with average capacity fade of 0.03% per cycle. Long-term coulombic efficiency values were 99.9 and 99.6% for 20 and 40% Ge/HCNS, respectively. Owing to the high volumetric capacity of Ge and porous structure of the HCNS, areal capacities of ~2.5 mAh/cm2
could be obtained by slurry casted techniques. Performance comparisons of multiple Ge/HCNS compositions with differing cycling environments will be presented.

(1) Michael J. Wagner, J. Thomas McKinnon, J. Cox and K. Gneshin, “Hollow Carbon Naonsphere Based Secondary Cell Electrodes”, United States Patent 8,262,942, September 11, 2012.

Figure 1
Three-Phase 3D Reconstruction of Li-Ion Batteries Electrodes Via FIB-SEM Tomography
Authors: Liu Zhao , Wang Hongqian , Singh Deepak P. , Wagemaker Marnix , Faber Katherine T , Barnett Scott A
Published: February 2020

Three-dimensional (3D) reconstructions of lithium-ion battery electrodes provide quantitative microstructural characteristics and input for 3D computational modeling of electrode lithiation and de-lithiation (1-3).  In much of the work reported to date, it was not possible to identify all three electrode phases – oxide particles, carbon, and electrolyte – because there was little or no image contrast between the carbon-based epoxy used to fill the pore regions of the electrode (after electrolyte removal) and the carbon phase (4).  Recently, it was shown that filling with a silicone resin allows good electrolyte/carbon contrast, although the high viscosity of the resins may make effective pore filling difficult (5).  

In this work, three-phase 3D reconstructions of a commercial LiCoO2 cathode and lab-made LiFePO4 cathodes (6) are demonstrated using a low viscosity silicone resin as a filling material.  As illustrated in Figure 1, contrast among oxide, carbonaceous materials (conducting carbon and binders, CB) and resin-filled porosity (electrolyte space) is obtained using focused ion beam-scanning electron microscopy tomography. Structural parameters including, phase volume fraction, surface area, particle size distribution, pore connectivity and tortuosity are extracted for electrode microstructure-performance correlation analyses. For the commercial LiCoO2 cathode, the electrolyte tortuosity within the electrode is found to be inhomogeneous. For LiFePO­4 cathodes, the microstructure characteristics are compared with conventional electrodes and those with additional large-scale pores added using a sacrificial templating technique. The improved high rate performance found in the templated LiFePO4 electrode can be explained by 3D microstructural characteristics created by the sacrificial template.  The present study demonstrates the importance of obtaining all three phases for accurate analysis of microstructure-performance correlations.

1.      Z. Liu, J. Scott Cronin, Y.-c. K. Chen-Wiegart, J. R. Wilson, K. J. Yakal-Kremski, J. Wang, K. T. Faber and S. A. Barnett, Journal of Power Sources, 227, 267 (2013).

2.      Andreas H. Wiedemann, Graham M. Goldin, Scott A. Barnett, Huayang Zhu and R. J. Kee, Electrochemica Acta, 88, 580 (2013)

3.      T. Hutzenlaub, S. Thiele, N. Paust, R. Spotnitz, R. Zengerle and C. Walchshofer, Electrochimica Acta, 115, 131 (2014).

4.      J. R. Wilson, J. S. Cronin, S. A. Barnett and S. J. Harris, Journal of Power Sources, 196, 3443 (2011).

5.      M. Ender, J. Joos, T. Carraro and E. Ivers-Tiffee, Journal of the Electrochemical Society, 159, A972 (2012).

6.      D. P. Singh, F. M. Mulder, A. M. Abdelkader and M. Wagemaker, Advanced Energy Materials, 3, 572 (2013).

Figure 1