bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation Study Between 3D Three-Phase Electrode Morphology and Li-Ion Battery Performance: A Case for LiFePO4
Authors: Wang Hongqian , Liu Zhao , Verhallen Tomas , Singh Deepak , Wagemaker Marnix , Barnett Scott A 
Published: February 2020

It is well known that the microstructure of the Li-ion battery (LIB) electrode can largely impact performance of LIBs. One approach to improve the performance of the LIBs is to gain insight in the correlations between the complex heterogeneous microstructure existing of active material, conductive additive and electrolyte, providing the required electronic and ionic transport. In a recent study we successfully demonstrated a simple and cost effective templating technique utilizing hydrogen carbonate salts to enhance the power density of LiFePO4electrodes without compromising the electrode density [1]. The applied templating method improves the capacity retention at high rates significantly. More importantly, the template only results in a slight increase in the porosity, leading to a combination of large tap density (high volumetric energy density) and large power density. The electrochemical data analysis indicates the better performance of templated electrodes may due to better interconnectivity and tortuosity within electrolyte induced by the template. However, direct evidence to correlate the microstructure of the templating electrode with LIBs performance is still needed.
In this work, by combining focused ion beam-scanning electron microscopy (FIB-SEM) and neutron depth profiling (NDP), we have obtained three-phase 3D electrode microstructure and Li-ion concentration profiles to better understand the improved rate performance of the templated LiFePO4 electrodes. Although it is proposed that the hierarchical interconnected porosity in the templated sample can enhance the electrode rate performance, no significant electrolyte tortuosity differences were found between the conventional and carbonate templated LiFePO4 electrodes. Surprisingly, although the same amount of CB was used in the two electrodes, a better electronic conductive CB network was observed for the templated sample (Figure 1 a, b), enhancing the activity of LiFePO4 at near the electrolyte-electrode interface as directly observed with NDP. Moreover, the CB structure in the templated electrode possesses a less tortuous pathway for electron transport, and the tortuosity distribution is less heterogeneous than in the conventional electrode, as shown in Figure 1 c-f. This results from 3D microstructure analysis is consistent with the NDP result where the templated electrodes show enhancing charging/discharging activity near the electrolyte-electrode interface than conventional LiFePO4electrode. The results demonstrate that the templated electrode has better charge transport network, which result in improved performance.
[1] Singh, D. P.; Mulder, F. M.; Abdelkader, A. M.; Wagemaker, M. Advanced Energy Materials
2013, 3, 572.

Figure 1
A New Thermally Stable and Conducting Electrolyte Based on Litdi As Lithium Salt for Li-Ion Batteries
Authors: Berhaut Christopher Logan , Schmidt Gregory , Timperman Laure , Lemordant Daniel , Anouti Mérièm 
Published: February 2020

Most of the LiBs used in electrical devices currently available contain lithium hexafluorophosphate (LiPF6) dissolved in a mixture of alkylcarbonates as the electrolyte. The main reasons for this [1] are the high conductivity of LiPF6 solutions, the formation of a protective SEI layer on graphite and its ability to passivate aluminum, a low-cost metal which can be used as a current collector. Other advantageous properties, which should also be observed by all LiB electrolytes, include low viscosity and a large life-span without safety risks, especially when damaged. However, the thermodynamic instability and moisture sensitivity of LiPF6 induce high risks of releasing HF and/or PF5 via its thermal decomposition or hydrolysis in the presence of traces of water. These drawbacks have been highly criticized justifying the importance in finding a replacement. Owing to (i) its high thermal stability, (ii) low sensitivity to the presence of water and (iii) its electrochemical stability [2], the lithium 4,5-dicyano-2-trifluoromethyl-imidazole (LiTDI) is seen as a promising substitute for LiPF6in LiBs.
In a previous study [3] the poor dissociation of ion pairs (IP) of LiTDI in electrolyte solutions was discussed and the IP dissociation coefficient was found to be around 30 % in an ethylene carbonate/dimethyl carbonate (EC/DMC) mixture. The power capability of LiTDI in EC/DMC with an added 2% FEC in half-cells, using either a NMC or a graphite electrode, and in full NMC/graphite systems was investigated and compared to that of LiPF6 in the same solvent mixture. It was noticed that both lithium salts performed equally within graphite half-cells but not in the NMC half-cells where a greater capacity loss was observed in the case of the LiTDI based electrolyte when increasing the NMC lithiation speed. The reason was attributed to the lower IP dissociation of LiTDI; LiPF6 being 85% dissociated in EC/DMC. Taking into account this observation a new solvent mixtures is proposed. We present here the results obtained using this new solvent mixture allowing a better dissociation of LiTDI (37 %), a higher conductivity (8.5 mS.cm-1 instead of 6.1 mS.cm-1in EC/DMC at 25°C) and a lower viscosity (2.4 mPa.s instead of 2.8 mPa.s in EC/DMC at 25°C). In addition a better power capability is achieved at higher current rates.
1. Eshetu, G.G., et al., LiFSI vs. LiPF6 electrolytes in contact with lithiated graphite: Comparing thermal stabilities and identification of specific SEI-reinforcing additives. Electrochimica Acta, 2013. 102(0): p. 133-141.
2. Niedzicki, L., et al., New covalent salts of the 4V class for Li batteries. Journal of Power Sources, 2011. 196(20): p. 8696-8700.
3. Berhaut, C.L., et al., LiTDI as electrolyte salt for Li-ion batteries: transport properties in EC/DMC. Electrochimica Acta, 2015. 180: p. 778-787.
Rational Design of 5V Electrolytes
Authors: Flamme Benjamin , Haddad Mansour , Phansavath Phannarath , Vidal Virginie , Chagnes Alexandre 
Published: February 2020

The development of new technologies for electrochemical energy storage is one of the main challenges of the next decades. Many hopes now rely on lithium-ion batteries (LiBs) that have invaded the market of laptops and which appear to be the best choice with the short time for electric vehicles, and perhaps for network applications (electricity storage from wind turbines or solar cells for example). Many works concern the search for cathodes with high-energy density but only few studies focus their research on the synthesis of new dipolar aprotic organic solvents for LiBs electrolytes. Thus, there is a need to deviate from traditional approaches for identifying new electrolytes stable to high voltage that are based on "Trial and Errors" approaches. To alleviate this issue, a collaborative project funded by the French Research Agency (ANR) and reuniting multidisciplinary research groups that combines highly and specific complementary skills in organic chemistry, electrochemistry, solution chemistry, thermodynamics and theoretical chemistry was launched in October 2014. The present paper aims at presenting recent advances from this group on the design of new electrolytes for high-voltage batteries.
First, a critical review of the physicochemical and electrochemical properties of the electrolytes will be presented in this talk (boiling and melting points, viscosity, ionic conductivity in the presence of lithium salts, oxidation potential, etc.). This critical review highlights the lack of homogeneity in the literature data for performing rational design of electrolytes by means of quantitative structure-property relationship calculations (QSPR). Therefore, these data were completed and homogenized by performing new experiments. In particular, a set of 20 new dipolar aprotic organic solvents were synthesized and characterized.
Second, the physicochemical properties of these new dipolar aprotic organic solvents including viscosity, ionic conductivity and their electrochemical behaviors on graphite, LiCoO2, NMC and Lithium rich electrodes as well as platinum and glassy carbon electrodes will be presented and discussed. In particular, their anodic stability will be discussed based on DFT calculations giving interesting information at the molecular level.
Finally, this talk will give the main drawbacks and the next challenges in the design of new electrolytes for 5V lithium-ion batteries.
Ionic Liquid - Alkyl Carbonate Hybrid Electrolytes: Understanding Their Interfacial Electrochemistry in Lithium Batteries
Authors: Theivaprakasam Sowmiya , MacFarlane Douglas R , Mitra Sagar 
Published: February 2020

The electrolytes for lithium batteries, are an important area of research as it is believed that small changes in either the composition or the concentration is expected impact performance. Current electrolytes are limited in terms of their thermal stability, operation temperature window, metal dissolution and high potential operation. Room temperature Ionic liquids (RTILs) are potential electrolyte ingredients as they can exhibit better electrochemistry in a wider potential window and high thermal stability1. However their use is hampered by the interfacial issues with graphite electrodes and also their viscosity2. The current study is focused towards electrolytes being a mixture of ionic liquids in conventional electrolyte components3. The studies were carried out with an optimized amount of ~40% N-Methyl-N-Propyl Pyrrolidinium bis (trifluoromethanesulfonyl) imide[C3mpyr][TFSI] in a mixture of LiPF6and the alkyl carbonates, also known as Hybrid Electrolytes(HE), and was focussed towards understanding the synergistic benefits evolved at the interface upon ionic liquid addition. The viscous effects of ionic liquids were alleviated by the alkyl carbonates in the solution.
As the ionic liquids, are known for their thermal stability, their addition produces a positive impact on the thermal stability of the hybrid electrolytes. Lithium symmetric cell studies were carried out in the conventional electrolyte (LP30), pure ionic liquid and the hybrid combination to look into the synergy brought by this combination. The combination lowers the overpotential in the symmetric cells as shown in Figure 1a. The combination also widens the temperature of operation of these batteries both on the low and high temperature scales. Further studies were carried out of the electrochemical performance of hybrid electrolytes with commercial battery cathodes where the performance of these combination gives better performance than the conventional system. The effect of metal dissolution on LiFePO4cathodes on these electrolytes were compared upon storage, and a clear distinction was observed on the separators from the aged cells dismantled after 30 days as shown in the Figure 1b & 1c inset. The EDAX analysis of such separators also confirms the traces of iron as shown in Figure 1b&1c.
Further morphological studies were also carried out on delithiated cathodes and it appears that the ionic liquid forms a protective layer on the cathode which helps in achieving a better cyclic stability of the electrodes. On the whole, addition of ionic liquid in the alkyl carbonate system helps in the thermal stability, interfacial kinetics and better cyclic stability.
References
1. MacFarlane, D. R. et al,Acc. Chem. Res. 40, 1165–1173 (2007).
2. Navarra, M. A., MRS Bull. 38, 548–553 (2013).
3. Theivaprakasam, S., MacFarlane, D. R. & Mitra, S.,Electrochim. Acta 180, 737–745 (2015).

Figure 1
Atomic Layer Deposition of HfO2 at Anode/Electrolyte Interface for Stable Anodes in Li and Na Ion Battery Applications
Authors: Ahmed Bilal , Alshareef Husam 
Published: February 2020

Recently, atomic layer deposition (ALD) has emerged as a promising and powerful technique to fabricate nanostructured electrodes and improve electrode/electrolyte interface in energy storage devices such as Li and Na ion batteries. In this project, we have deposited an electrochemically inert oxide material, hafnium oxide (HfO2), on different anode materials. We demonstrate that a nanoscale layer of HfO2 on zero dimensional (0D) SnO2 nanospheres, one dimensional (1D) MoO3 nanorods and two dimensional (2D) MoS2 nanosheets significantly improves the cyclic stability, when these materials were applied as anode in Li ion batteries. Moreover, HfO2 coated MoS2 nanosheets were tested as anode material in Na ion batteries and, after 50 charge/discharge cycles, HfO2 coated MoS2 electrodes retained 91% of the initial capacity and bare MoS2 electrodes retained only 63%.
Most importantly, the mechanism of capacity retention was explained by ex situ high resolution transmission electron microscopy (HRTEM), electrical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray diffraction. We showed that capacity retention is directly related to the degree of crystallinity retention after charge/discharge process. For instance, in case of MoO3, ex-situ HRTEM analysis showed that after 50 charge/discharge cycles, the crystal structure of bare MoO3 electrodes degrades severely while HfO2 preserves the crystal structure during charge/discharge process. Furthermore, it was found that thickness and amorphous nature of HfO2 layer plays critical role because Li+ ions has to diffuse through this layer. In summary, a mechanistic insight into capacity retention after HfO2 coating has been provided by post – electrochemical ex-situ analysis.
Solid Electrolytes: Bulk and Grain Boundary Li Ion Conductivity of Li1.5Al0.5Ti1.5(PO4)3
Authors: Breuer Stefan , Prutsch Denise , Ma Qianli , Epp Viktor , Preishuber-Pflügl Florian , Tietz Frank , Wilkening Martin 
Published: February 2020

Lithium aluminium titanium phosphate (LATP) belongs to the class of materials exhibiting very high Li+ ionic conductivities. While many impedance studies can be found in literature that report on overall ion conductivities, a discrimination of bulk and grain boundary electrical responses via conductivity spectroscopy has rarely been reported so far. Here, we took advantage of impedance measurements that were carried out at low temperatures to separate bulk contributions from the grain boundary response. It turned out that bulk ion conductivity is by at least three orders of magnitude higher than ion transport across the grain boundary regions. At temperatures well below ambient long-range Li ion dynamics is governed by activation energies ranging from 0.26 to 0.29 eV, depending on the sintering conditions. As an example, at temperatures as low as 173 K, the bulk ion conductivity, measured in N2 inert gas atmosphere, is in the order of 8.1 x 10−6 S cm−1. Extrapolating this value to room temperature yields ca. 3.4 x 10−3 S cm−1 at 293 K. Interestingly, exposing the dense impedance pellets to air atmosphere over a long period of time causes a significant decrease of bulk ion transport. The effect can be reversed if the phosphate is calcined at elevated temperatures again.
How Crystallographic Evolution of Sodium within Electrodes during Sodium-Ion Battery Function Can be Used to Make Better Electrodes?
Authors: Sharma Neeraj 
Published: February 2020

A large proportion of the function of batteries arises from the electrodes, and these are in turn mediated by the atomic-scale perturbations or changes in the crystal structure during an electrochemical process (e.g. battery use). Sodium insertion and extraction into/from electrodes during charge/discharge can lead to dramatic changes in the crystal structure and these are typically detrimental to performance. By understanding how and when large structural changes occur, electrochemical limits and solid state chemistry can be invoked to provide solutions. Therefore, to understand battery function and improve performance it is critical to probe the crystal structure evolution in situ or operando - while an electrochemical process is occurring inside a battery.
This presentation will showcase some of our recent work on tracking the structural evolution of electrodes during battery operation with a particular emphasis on the sodium location and distribution. Examples will include studies on the Na3V2O2x(PO4)2F3-2x system, Fe[Fe(CN)6]1-x.yH2O framework materials, layered P2 and O3 polymorphs of Na2/3Fe2/3Mn1/3O2 at varying current rates and layered P2 Na2/3Mn0.8Ti0.1Fe0.1O2 and Na2/3Mn0.8Mg0.2O2materials. The relationship between electrochemical parameters such as current rate, number of cycles and battery history will be tied with phase transitions and sodium site occupancy evolution. Such detailed relationships will help to build an atomic scale picture of electrode functionality.
The message in the presentation will be the ability to literally “see” how sodium behaves in such electrodes and thus build a sodium-centred picture of battery function. For room temperature sodium-ion batteries based on intercalation chemistry to become a reality the insertion/extraction process needs to be understood and manipulated.
Development of MnCo2O4 Microspheres Based Air Electrode for Rechargeable Sodium - Air Batteries
Authors: Shang Mengshi , Liu Yu 
Published: February 2020

Rechargeable metal-air batteries have been gained much attention because of their high energy densities. As a newly developed member of metal-air batteries,great efforts have been devoted to sodium-air batteries(SABs). SABs are still in an infant stage and many problems needs to be solved.As well-known, cathode is the key of oxygen reduction reaction (ORR) and oxygen evolution reduction(OER). In this work, MnCo2O4 microspheres have been synthesized and demonstrated as a highly efficient electrocatalyst for the air cathode of sodium-air cell. The cell shows an initial discharge capacity of 7709.4 mAh/g(based on the carbon mass vs. Na). The crystal structure and phase purity of MnCo2O4 are confirmed from powder XRD patterns shown in Fig.1. The diameter of MnCo2O4 varies from 1 to 2 μm and the morphology has a high dependence on the synthesis temperature, as shown in Fig. 2. The electrochemcial performance of the MnCo2O4@ carbon black was compared with the carbon black as air electrode in oxygen evolution reduction(OER) and oxygen reduction reaction (ORR). For the first discharge profiles shown in Fig.3a, the discharge capacity of the MnCo2O4 microspheres is 4882.6 mAh/g, nearly about 10 times over carbon black. By the modification of the morphology, MnCo2O4 microspheres exhibited much greater discharge and charge abilities, as shown in Fig. 3b. The cycling stability of the as-proposed MnCo2O4 electrode was shown in Fig.3c.

Figure 1
Synthesis, Structure, and Properties of the New Intercalation Cathode Material MoO2.8F0.2
Authors: Incorvati Jared T , Wustrow Allison , Poeppelmeier Kenneth 
Published: February 2020

The widespread adoption of multivalent batteries is hampered by the lack of stable, reliable, high voltage cathodes that can reversibly intercalate divalent cations. In lithium-based systems, molybdenum trioxide has been studied for several years as a high capacity cathode material. Although its voltage is lower than other systems, e.g. V2O5, it has advantages including crystallographic stability on cycling. A key issue that is believed to limit its performance is that, as a d0 metal oxide, it has limited electronic conductivity at top of charge.1 In this poster we will be discussing the role of fluoride incorporation into the layered charged cathode MoO3 and its effect on the materials physical properties. Utilizing synthetic methodologies developed in our lab we have studied the fluoride solubility in the host material as a way to induce electronic conductivity across the whole range of use. We have shown that the maximum fluoride incorporation in the material yields a stoichiometry of MoO2.8F0.2. Incorporation above this value results in isolation of the perovskite phase MoO2.6F0.4. We have evaluated the material using multiple intercalating cations and compared it to the undoped parent material. While the electrochemical activity of the material using a lithium-based electrolyte is similar, remarkable differences have been observed when Mg is used as the cation. While the undoped material has little or no activity, the fluorinated materials shows excellent cycleability and structural reversibility.2

References:
(1) Spahr, M. E.; Novák, P.; Haas, O.; Nesper, R., Electrochemical insertion of lithium, sodium, and magnesium in molybdenum(VI) oxide. J. Power Sources
1995, 54, 346-351.
(2) Incorvati, J. T.; Wan, L. F.; Key, B.; Zhou, D.; Liao, C.; Fuoco, L.; Holland, M.; Wang, H.; Prendergast, D.; Poeppelmeier, K. R.; Vaughey, J. T., Reversible Magnesium Intercalation into a Layered Oxyfluoride Cathode. Chemistry of Materials
2016, 28, 17-20.

Figure 1
How New Advancements Enable a Position Change in the Science of Magnesium Batteries
Authors: Mohtadi Rana , Tutusaus Oscar , Arthur Timothy S. , Mizuno Fuminori 
Published: February 2020

Driven by the need to access higher energy densities beyond those offered by Li-ion batteries, rechargeable Mg batteries have been receiving increased interests. Although Mg metal is not competitive with Li metal on both specific capacity (2205 mAh g-1 vs. 3862 mAh g-1 for lithium) and redox potential levels (-2.3 V compared to -3.0 V for Li vs. NHE), it was found to be non-dendritic. In addition, Mg metal has a high volumetric capacity (3833 vs. 2046 mAh cm-3 for Li), and offers an opportunity for battery cost reductions owing its abundance in the earth crust (5th most abundant element). However, several technical challenges that hamper realizing practical rechargeable Mg batteries are currently present. For example, the absence of robust and practical high voltage/high capacity cathodes currently limits the energy density which could be harnessed using these systems.[1] Another major hurdle is caused by the type of electrolytes currently used in Mg batteries. At its very core, is the limitation induced by the incompatibility of Mg metal with simple ionic salts and non-ethereal solvents. This has limited the working electrolytes options to a handful of complex halogen systems which are corrosive. We have been pioneering the development of a new family of electrolytes based on a novel bottom-up design strategy to create highly performing simple type highly compatible Mg salts. Herein, we will explain our design concepts that guided the development of a new paradigm using boron-hydrogen salts and resulted in demonstrating the only ionic simple-type salts known to date that are highly compatible with Mg metal.[2,3]

References

[1] a) R. Mohtadi, F. Mizuno Beilstein J. Nanotechnol.
2014, 5, 1291–1311, b) H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci. 2013, 6, 2265-2279.
[2] a) R. Mohtadi, M. Matsui, T. S. Arthur, S.-J. Hwang, Angew. Chem. Int. Ed.
2012, 51, 9780 –9783; b) T. J. Carter, R. Mohtadi, T. S. Arthur, F. Mizuno, R. Zhang, S. Shirai, J. W. Kampf, Angew. Chem. Int. Ed.
2014, 53, 3173-3177, c) O. Tutusaus, R. Mohtadi, ChemElectroChem.
2014DOI: 10.1002/celc.201402207;
[3] O. Tutusaus, R. Mohtadi, T. Arthur. F. Mizuno, Angew. Chem. Int. Ed.
2015, DOI: 10.1002/anie.201412202R3.