bluuebunny/crossref_metadata_2025 huggingface dataset:
Invited Presentation: 4.7 V Li-ion cells: Nonsense or Possibility
Authors: Dahn Jeff , Downie Laura , Wang D. Y. , Aiken Connor , Ma Lin , Petibon Remi , Burns John Chris , Xia Jian , Camardese John , Li Sirong
Published: February 2020

One way to improve the energy density of Li-ion cells is to use high voltage positive electrode materials like LiNi0.5Mn1.5O4 [LNMO] or simply increase the upper cutoff potential when positive electrodes like Li[NixMnxCo1-2x]O2 [NMC] are used. This sounds simple, but there are numerous problems to overcome before high voltage Li-ion cells are a reality.

Many literature reports of Li/LNMO and LTO/LNMO cells present very promising behavior. However, most of the reports show charge discharge cycling at high rates, where many cycles can be accumulated in a short period of time. In such experiments, authors are able to “beat the clock” on parasitic electrolyte oxidation reactions which occur in cells. We recently showed using storage experiments on LTO/LNMO cells that electrolyte oxidation, as evidenced by rapid self discharge, is a huge problem [1, 2] that is ignored in most literature reports.

In this paper we discuss a number of the problems that occur in LTO/LNMO cells and high voltage graphite/NMC cells. These include:

1. Impedance increase at the positive electrode as the potential increases due to parasitic reactions.

2. Increases in parasitic heat as a function of cell voltage as measured using isothermal battery microcalorimetry

3. Increases in gas evolution as a function of cell potential, even when fluorinated solvents are used.

4. Decreases in coulombic efficiency as cell potentials increase.

5. Etc.

The results above paint a bleak picture about the future of Li-ion cells that can operate at 4.7 V.

Next, partial solutions to the problems above will be presented:

a) Electrolyte additives that can stabilize positive electrode impedance increases during high potential cycling will be discussed.

b) Electrolyte additives that can dramatically reduce parasitic heats evolved at high potentials will be discussed.

c) Materials that can dramatically lower electrolyte oxidation reactions at the surface of the positive electrode and are suitable as “shells” in core-shell materials will be discussed.

d) Electrolyte additives that can reduce gas evolution at high potential will be discussed.

e) Etc.

These encouraging results provide hope that real solutions can be found.
Iron Cyanides As a Cathode Material for Lithium-Ion Batteries
Authors: Shen Lian , Wang Zhaoxiang
Published: February 2020

Lithium ion battery is one of the most popular power sources for clean and efficient electrochemical energy storage and conversion. There are increasing interests for both the cathode and anode, in accordance with the development of portable electronic equipments, and automotive industry. As one of the potential alternatives, organic cathode1has advantages of low cost, environmentally friendly, easy fabrication compared to the inorganic cathodes. However, the low voltage plateau and poor cycle performance restrict its applications.

Iron cyanide and its analogs2
have been pursued as attractive materials for fundamental research and large scale industrial applications since its electrochemical activity was first reported in 1978. These zeolite-like compounds have perfectly 3D polymeric frameworks due to the asymmetric CºN anion. Its large open spaces can not only accommodate transition metal ions but also some small molecules. Redox reaction can also take place there thanks to the iron valence state for charge balance. These characteristics exactly offer the tunnels and spaces for the transport and storage of lithium ions.

Fe4[Fe(CN)6]33
is the foretype of prussian blue, its theoretical specific capacity is about 100 mAh/g with one charge transport of Fe2+/Fe3+. Here we synthesize this compound by a simple one-step precipitation method. The cell shows an initial specific capacity of 95.1 mAh/g and about 75% of its original capacity is retained after 50 cycles. In order to increase the specific capacity, Fe2+
was replaced with Fe3+ to provide more redox active sites. The as-prepared FeFe(CN)6 has a regular cubic structure with the particle size of 50 nm. Two redox peaks at 2.88V/3.19V and 3.81V/3.91V are observed by cyclic voltammetry, corresponding to the oxidation/reduction of the low spin Fe2+/Fe3+ adjacent to the carbon and the high-spin of Fe2+/Fe3+bonding to the nitrogen, respectively. Galvanostatic charge/discharge cycling shows that its initial discharge capacity is 137.3 mAh/g, and the capacity retention is 60% after 100 cycles. In addition, its rate performance is very excellent.

1. Y. Liang, Z. Tao and J. Chen, Advanced Energy Materials, 2012, 742-769.

2. A. A. Karyakin, Electroanalysis, 2001, 13, 813-819.

3. N. Imanishi, T. Morikawa, J. Kondo, R. Yamane, Y. Takeda, O. Yamamoto, H. Sakaebe and M. Tabuchi, J Power Sources, 1999, 81, 530-534.
One Pot Synthesis and Characterizations of Nanosize Lithium Metal Silicates and Lithium Metal Flurophosphates for Lithium Ion Battery Applications
Authors: Devaraju Murukanahally Kempaiah , Truong Quang Duc , Honma Itaru
Published: February 2020

Recently, orthosilicates and flurophosphates have been investigating for the cathode applications in lithium ion battery. Orthoslicate materials are built of abundant elements such as Si, Fe and Mn, which makes them cheap cathode materials for large scale high capacity batteries that can operate at higher temperatures1,2. Fluorophosphates have been considered as potential lithium insertion/ extraction cathodes3,4. Both, silicates and fluorophosphates have the ability of delivering two lithium ion discharge capacity (290-333 mAhg-1).

Herein, we present a supercritical fluid process to synthesize Li2MSiO4 and Li2MPO4F (M= Fe, Mn and Co) nanoparticles ranging from 5-50 nm and their electrode properties have been investigated. These cathode materials are synthesized via supercritical fluid process by controlling the size and shape. The supercritical synthesis was carried out at 300-450 oC for 5 min-30 min of reaction time using mixed solution of water, ethanol, EG as solvents and ascorbic acid, oleic acid and oleylamine as surfactants. The as-synthesized Li2MSiO4 and Li2MPO4F (M= Fe, Mn and Co) nanoparticles were characterized by XRD, TEM, TG-DTA and FTIR analysis. Further, the electrochemical property of Li2MSiO4 and Li2MPO4F (M= Fe, Mn and Co) cathode materials have been investigated by galvanostatic charge-discharge method.

Fig. 1 shows the TEM images of Li2FeSiO4 and Li2FePO4F nanoparticles synthesized by supercritical method at 300-450 oC for 5-30 min. The particles exhibited 5-50 nm in diameter with sphere like morphology. The different kind of morphology with variable size can be synthesized at supercritical conditions. The flower like morphology, rod like morphology and ultrafine particles were successfully synthesized and their electrochemical property was investigated. The charge-discharge curve of carbon coated Li2FeSiO4 and Li2FePO4F nanoparticles showed 180 mAhg-1 and 150 mAhg-1, respectively at 0.05C as shown in fig 1.

References

1) A. Nyten, et al. Electrochem.Commun., 2005, 7, 156.2) Y.X. Li, et al. J. Power Sources. 2007, 174, 528. 3) R. Dominko,.et al, J. Electrochem. Commun., 2006, 8, 217. 4) B.L. Ellis, et al. Nature Mater., 2007, 6, 749.

Fig.1 TEM image and charge discharge profile of Li2FeSiO4 and Li2FePO4F cathode nanomaterials
Study of Antisite Defects in LiCoPO4 Cathode Material and Their Change during Initial Charge/Discharge Cycle
Authors: Truong Quang Duc , Devaraju Murukanahally Kempaiah , Honma Itaru
Published: February 2020

Antisite cation exchange is the typical point defects in crystal lattices which have been the topic of extraordinary research interest in solid state physics and chemistry. The optical properties, electrical conductivity, ionic diffusion and resulting chemical properties, mass and charge transport behavior of the materials are heavily affected by the concentration and distribution of these defects in the crystal lattices, which has triggered considerable efforts in the control the exchange disorder to provide optimal performance in devices.

In lithium intercalation compounds, the lithium diffusion along the channel is highly anisotropic which is strongly depend on the cation ordering within the crystal lattices. The cation exchange disorder, namely the occupation of Li sites by transition metals, inevitably blocks the lithium ion diffusion pathway, thus directly affects the cathode performance in lithium-ion batteries. It has been clearly confirmed the presence of antisite defect in lithium-intercalated transition-metal oxides and phosphates by theoretical calculations, neutron diffraction and direct observation by advanced electron microscopy. It now turns to research on the local variations, transition metal relocation, structural change and their correlation to the voltage/capacity fading during the charge/discharge cycling. Many intensive investigation on the diffusion of transition metal ions on the layered metal oxides during the cycling process. However, the relocation of metal ions in ordered lithium metal phosphates during the intercalation-deintercalation reactions, remains unknown, although this relocation undoubtedly influence mass and charge transport behavior.

In this presentation, by a combination of high-angle annular dark-field (HAADF) and annular bright-field (ABF) STEM, we observed the local variation of cobalt ions from M2 sites to vacancy M1 sites in olivine lithium cobalt phosphates upon the delithiation process (Ref. 1). The finding provides the intrinsic evidence for the capacity fading of LiCoPO4 cathode materials.

1. Truong, Q. D., Devaraju, M. K., Tomai, T. & Honma, I. Direct observation of antisite defects in LiCoPO4 cathode materials by annular dark- and bright-field electron microscopy. ACS Appl. Mater. Interfaces 5, 9926−9932 (2013).
Snsb@CNT Nanostructures Rooted in Graphene and Its Application in Sodium Ion Batteries
Authors: Li Li , Seng Kuok Hau , Li Dan , Liu Hua Kun , Guo Zaiping
Published: February 2020

The uniform SnSb alloy core/carbon-shell nanotubes growing on the graphene sheets were synthesized as the potential anode for sodium ion batteries by two steps. Typically, SnSb nanoparticles were firstly decorated on reduced graphene oxide by the hydrothermal method, and then the precursors were reduced by thermochemical vapour deposition with C2H2/Ar gas. In order to obtain uniform SnSb-core/carbon-shell nanotubes, the precursors were optimized with different C2H2/Ar gas flow rates (10:400, 20:400 and 40:400 sccm/sccm), and different annealing temperature varying from 550 to 700 oC. The morphologies and structures were characterized by SEM and TEM. Under the annealing temperature of 650 oC and C2H2/Ar gas flow rate of 20:400, the nanotubes distribute on graphene sheets more uniformly compared to that obtained from other temperatures and flow rates, and the average diameter of the nanotubes is around 100 nm. Moreover, the SnSb-core/carbon-shell nanotubes were used as anode materials for sodium ion batteries. The electrochemical performance for sodium ion batteries is significantly affected by the electrolyte. In this work, different electrolytes such as 1M NaClO4 in PC, 1M NaPF6 in PC with or without FEC and 1M NaClO4 in PC/FEC have been applied in order to optimize the electrochemical performance of composite anode materials for sodium storage. It is found that cells using electrolyte without FEC exhibit a higher specific capacity compared to those using electrolyte with FEC, however, the coulombic efficiency of these cells is relatively lower. The cell delivers an initial reversible capacity of 500 mAh/g with a coulombic efficiency of 66% in the electrolyte of 1M NaPF6 in PC without FEC, but the capacity collapsed after about 15 cycles. When FEC is added in the electrolyte, however, the cycling performance is remarkably improved. Only slight decay can be observed after 80 charge/discharge cycles. The excellent electrochemical performances compared to other SnSb-based anodes can be attributed to the efficient prevention of graphene restacking by SnSb@CNT decoration, the protection role of CNT shell and the support of graphene sheets.
A Zero-Strain P2-Layered Na0.66[Li0.22Ti0.78]O2 As New Anode Material for Room-Temperature Sodium-Ion Batteries
Authors: Wang Yuesheng , Yu Xiqian , Xu Shuyin , Bai Jianming , Xiao Ruijuan , Hu Yong-Sheng , Li Hong , Yang Xiaoqing , Chen Liquan , Huang Xuejie
Published: February 2020

Room-temperature sodium storage technology has attracted more and more interest in the electrical energy storage field, particularly for large-scale applications in renewable solar and wind power as well as smart grid. However, the development of suitable anode materials remains a big challenging issue for long-life sodium-ion batteries.

In this presentation, we will introduce a new “zero-strain” anode, Na0.66[Li0.22Ti0.78]O2 with P2-layered structure, as a promising material for room-temperature long-life sodium-ion batteries. There are several significantly important results obtained in this work: the reversible capacity is ca. 110 mAh/g; the average sodium storage voltage is ca. 0.75 V; the volume change during sodium insertion and extraction is only 0.77%, showing the “zero-strain” characteristics; the material exhibits very long cycling performance, over 1200 cycles with a capacity retention of 75%; the measured apparent Na+ ion diffusion coefficient is ca. 1x10-10 cm2/s. It is also very interesting to find that the final discharge product is actually a mixture of several phases which also retain the P2-structure confirmed by in situ and ex situXRD. The difference in these several P2-phases lies in different sodium composition and occupation (2b, 2d) in the alkali layer.

This contribution demonstrates that P2-Na0.66[Li0.22Ti0.78]O2is a promising anode material for the development of rechargeable long-life sodium-ion batteries.

References:

[1] Y. S. Wang, X. Q. Yu, S. Y. Xu, J. M. Bai, R. J. Xiao, Y.-S. Hu, H. Li, X.-Q. Yang, L. Q. Chen, X. J. Huang,
Nat. Commun.
2013, 4, 2365.

[2] H. L. Pan, Y.-S. Hu, L. Q. Chen,
Energy &Environ. Sci.
2013, 6, 2338-2360.

Figure 1
a) P2-structure, b) Na+ ion diffusion, c) Volume change, d) Discharge/charge curves, e) Cycling performance, f) XRD refinement of final discharged product
Synthesis and Electrochemical Properties of Nano WO3/C Composite for Lithium-Ion Batteries
Authors: Feng Chuanqi
Published: February 2020

The WO3/C nano-belts composite was prepared through a hydrothermal synthesis method by using (NH4)10H2(W2O7)6, H2C2O4·2H2O and different proportions of glucose as reactants. The WO3/C samples were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the samples were investigated. The results show that the morphology of the samples was nano-belts with a width of about 5~15 nm structure. The electrochemcial testing showed that the WO3/C nano-belts with the 20 wt.% of the raw material weight of glucose exhibited good lithium storage properties, with a high reversible capability (700 mAh/g at current density of 50 mA/g) and stable lithium-ion insertion/de-insertion reversibility. Besides, the WO3/C nano-belts bahaved rate capacity and outstanding cycle performance. It is a promising anode material for lithium ion battery application.
Nanostructured Anatase TiO2 - from Lithium- to Sodium-Ion Anodes
Authors: Bresser Dominic , Wu Liming , Oschmann Bernd , Mueller Franziska , Buchholz Daniel , Tahir Muhammad Nawaz , Tremel Wolfgang , Zentel Rudolf , Passerini Stefano
Published: February 2020

Lithium-ion batteries are nowadays the energy storage device of choice for portable electronic devices due to their superior energy and power density. Consequently, they are considered also as most promising power source for large-scale applications as, for instance, electric vehicles [1–3]. However, for such applications further improvement of the existing technology is required in terms of energy, power, and particularly safety. Beside Li4Ti5O12, which is already used in commercial cells, anatase TiO2 – particularly in its nanostructured form - is seriously considered as alternative anode material to replace graphite due to its enhanced safety and rate capability [4,5].

Remarkably, anatase TiO2 was recently demonstrated to be highly promising as high power anode material for sodium-ion batteries [6,7], which are considered as low-cost alternative for lithium-ion batteries. These batteries are especially interesting for stationary energy storage applications in order to balance the energy supply provided by renewables, for which size and weight are less important, while cost are of major importance.

Herein we will report our latest results on the utilization of nanostructured anatase TiO2 for lithium- and sodium-ion batteries, including the importance of carbonaceous coatings and percolating networks, and highlight the major differences regarding the lithium- and sodium-ion storage mechanism.

References

[1] M. Armand, J.-M. Tarascon, Nature 451 (2008) 652.

[2] B. Scrosati, J. Garche, J. Power Sources 195 (2010) 2419.

[3] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 4 (2011) 3287.

[4] C. Jiang, J. Zhang, J. Mater. Sci. Technol. 29 (2013) 97.

[5] D. Bresser, E. Paillard, E. Binetti, S. Krueger, M. Striccoli, M. Winter, S. Passerini, J. Power Sources 206 (2012) 301.

[6] Y. Xu, E. Memarzadeh Lotfabad, H. Wang, B. Farbod, Z. Xu, A. Kohandehghan, D. Mitlin, Chem. Commun. 49 (2013) 8973.

[7] L. Wu, D. Buchholz, D. Bresser, L. Gomes Chagas, S. Passerini, J. Power Sources 251 (2014) 379.
Synthesis and Characterization of Nanoporous NaMn2O4 electrode Material for Sodium-Ion Battery
Authors: Wei Yiying , Chen Shuangqiang , Wang Guoxiu , Zhu Jianguo
Published: February 2020

Lithium is relative expensive and will be exhaust one day due to the limitation of lithium resources on the earth. In contrast to lithium, sodium is more abundant and lower cost of sodium-containing precursors, leading to sodium-ion battery is a promising energy storage device for large-scale systems. 1-3

In the present work, we synthesized NaMn2O4 spheres with mesoporous structure via a revised microwave assisted high temperature solid-state reaction. As shown in Fig. 1a, the powders consist of plurality of NaMn2O4 spheres, ranging from 2 um to 5 um. The high magnification SEM image shows that the materials possess mesopores with the diameter around 20 nm. The uniform mesoporous structure optimizes the sodium ion diffusion path, and facilitates the transportation of ions. The electrochemical performances of the nanoporous NaMn2O4were investigated as the electrodes for sodium-ion battery. The three cycles of consecutive cyclic voltammogram (CV) at a scan rate of 0.1 mV/s are shown in Fig. 1c. The CV curve reveals the materials have excellent reversibility. It has five cathodic redox peaks at around 2.4 V, 2.5 V, 2.85 V, 3.47 V and 4.17 V in the voltage range 2.0 V to 4.5V, respectively, indicating the multi-step insertion of the sodium ion into NaMn2O4 nanostructures. Five anodic peaks were also observed at around 2.35 V, 2.6 V, 3.2 V, 3.5 V and 4.25 V are ascribed to the sodium ion deintercalation process, respectively. The five pairs of redox peaks demonstrate the excellent reverse capability of the materials. Furthermore, there are a bit of shifts with the increase of the cycles, leading to good cyclability.

References

1. M. D. Slater, D. Kim, E. Lee and C. S. Johnson, Advanced Functional Materials, 2013, 23, 947-958.

2. S. Wenzel, T. Hara, J. Janek and P. Adelhelm, Energy & Environmental Science, 2011, 4, 3342-3345.

3. A. Darwiche, C. Marino, M. T. Sougrati, B. Fraisse, L. Stievano and L. Monconduit, Journal of the American Chemical Society, 2012, 134, 20805-20811.
Virus-Enabled 3D Electrodes with Rapid Electronic Charge Transport
Authors: Ransil Alan , Burpo Fred John , Belcher Angela M
Published: February 2020

For 3D battery electrodes exhibiting extremely high rate capability (several hundred C), it is necessary to engineer rapid electronic conduction through the active matrix. In order to achieve this, we present a novel and highly tunable system employing an engineered M13 bacteriophage virus as a template for lithium-ion battery positive and negative electrodes. Genetically modified viruses are first cross-linked in order to form a hydrogel, then an electroless deposition process is used to form biotemplated nanoscale networks. We demonstrate control over the geometry of these networks viagenetic manipulation of the virus and through processing conditions, engineering tunable nanostructures with pore sizes and strut widths making them amenable for use as 3D current collectors. These networks are shown to be highly conductive, to retain a nanoporous architecture following heat treatments in excess of 450°C, and to be mechanically flexible. After fabricating such biotemplated nanostructures, both positive and negative electrodes were produced through subsequent processing steps. Electrodeposition was used to deposit manganese oxide onto nickel and tin was deposited onto copper through galvanic displacement, demonstrating the compatibility of these biotemplated current collectors with a wide range of active materials. Furthermore, as M13 bacteriophage have been engineered in our lab to bind a wide range of inorganic materials, the use of this surface functionality to directly embed active material particles into metallic current collectors is being explored. The high degree of control over nanostructural morphology inherent to this fabrication method combined with the mechanical flexibility of the resulting electrodes is expected to enable novel strategies for the integration of biotemplated batteries into vehicles ranging in size from automobiles to micro-robots.

Figure 1 (attached): Nanoporous nickel current collector fabricated through M13 virus-based biotemplating process
Electrochemical Performances of Si Nanocrystals Embedded SiOx Nanosphere As a High Capacity Anode Material for Lithium-Ion Battery
Authors: Park Eunjun , Park Min-Sik , Lee Jaewoo , Kim Young-Jun , Kim Hansu
Published: February 2020

Si has gained much attention as anode materials for lithium-ion battery due to its high theoretical capacity (3,580 mAhg-1) and low standard oxidation potential (0.4 V vs. Li/Li+). Despite these features, Si anode materials still have limits to commercial uses by poor cycle performance associated with their mechanical pulverization of Si due to severe volume change during alloying/dealloying with Li. To overcome this problem, various approaches have been suggested. In particular, the composites, which are composed of active Si and inactive buffer material, showed promising approaches for reducing the mechanical strain during cycles. On the other hand, nanostructuring of active materials would be helpful for further improvement of cycle performance. After heat treatment of Si/SiOx precursor at 1200 °C under inert atmosphere, we obtained Si nanocrystals embedded SiOx nanospheres with a size of 200 nm, in which about 10 nm sized Si nanocrystals are embedded in amorphous SiOx matrix. In order to improve electrical conductivity of Si/SiOx nanocomposites, carbon layer was coated on the surface of Si/SiOxnanocomposites.

The Si/SiOx nanospheres and C-coated Si/SiOx nanospheres were characterized by a field emission scanning electron microscope (FESEM), a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) patterns, solid state 29Si magnetic angle spinning nuclear magnetic resonance (MAS NMR) and X-ray photoelectron spectroscopy (XPS) analyses.

The C-coated Si/SiOx composites showed a reversible capacity of 950 mAh/g-1 at current density of 200 mAg-1 with stable cycle performance over 100 cycles and high rate capabilities. In this presentation, the electrochemical properties of the C-coated Si/SiOx nanocomposites will be discussed in more detail.
Li Storage Properties of (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2 Solid Solution Cathode Materials
Authors: Li Jiangang , Wang Lei , Chen Jiuhua , He Xiangming
Published: February 2020

In view of cost and safety, some Fe-Mn based cathode materials such as LiFeO2-Li2MnO3 solid solution [1], Li(Li0.15Ni0.21Fe0.21Mn0.45)O2
[2] and Li1.2(Mn0.32Ni0.32Fe0.16)O2
[3] etc., were investigated in recent years. Our research group also developed a new cobalt free LiFeO2-Li2MnO3 based solid solution with a composition of Li(Li0.23Mn0.47Fe0.2Ni0.1)O2 to obtain high capacity of 277.4 mAh/g and better cycling stability [4]. In order to further optimize the solid solution composition to obtain the best electrochemical performance, the effects of solid solution composition on Li storage properties should be investigated thoroughly.

In this paper, a series of materials with the composition of (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2(x+y£0.5)were prepared by sol-gel method, and the effect of annealing condition on the structural and electrochemical properties of as-prepared materials were investigated. The results reveal that all of materials prepared at 600 oC ~800 oC show pure layered a-NaFeO2 phase. However, the electrochemical performance varies with the solid solution composition. As shown in Fig.1, as-prepared materials with x+y=0.3~0.4 exhibit better cycling performance, indicating that suitable amounts of composited LiFeO2 and LiNiO2 in the solid solution is benefit for reducing the transformation of layered Li[Li1/3Mn2/3]O2 to spinel phase, and suitable amounts of composited Li[Li1/3Mn2/3]O2 can also restrain cubic LiFeO2 formation. Obvious cooperative effects are observed. In addition, as-prepared samples with high capacity of >210 mAh/g also distribute in this composition range, as shown in shadow area of Fig.1. However, high capacity of above 240 mAh/g can only be obtained while the material with composition of x/y<0.6 and x/y>2 in the shadow range. Further detailed discussion will be presented in the meeting.

References

[1] M. Tabuchi, Y. Nabeshima, T. Takeuchi, K. Tatsumi, J. Imaizumi, Y. Nitta, J. Power Sources 195 (2010) 834.

[2] X. Zheng, L. Cao, W. Zhu, X. Qiu, Acta Chimica Sinica,65 (2007) 571.

[3] K. Karthikeyan, S. Amaresh, G.W. Lee, V. Aravindana, H. Kim, K.S. Kang, W.S. Kim, Y.S. Lee, Electrochim. Acta 68 (2012) 246.

[4] Jiangang Li, Li Wang, Lei Wang,et al., J. Power Sources 244 (2013) 652.

Fig.1 The investigated (1-x-y)Li[Li1/3Mn2/3]O2-xLiFeO2-yLiNiO2 solid solution cathode materials
Enhanced High-Temperature Storage Performance of Li-Ion Batteries Using Stoba Polymer Coated on a Lithium Transition Metal Oxide Cathode Material
Authors: Wu Hung-Chun , Li Yu-han , Su Joyce , PAN Jing Pin
Published: February 2020

ITRI in Taiwan has developed a polymeric cathode coating material, known as self-terminated oligomer with hyper-branched architecture (STOBA) can improve the safety and high temperature cycle ability, also can suppress the thermal runaway. In this research, the STOBA was coated on a mixture of NMC and LMO. 18650-type cells test show the capacity recovery ratio after storage for 30 days at 55°C, the batteries without STOBA-coating have large capacity deterioration than with STOBA. Furthermore, the batteries were dissemble after aging, the electrolyte was analyzed by ICP, dissoluted Mn ion was detected in the electrolyte solution. The Mn dissolution quantity of mixture electrode without STOBA coating almost 2 time larger than the sample with 2 wt.% STOBA coating electrode. Mn dissolution of mixture electrode restrained by STOBA coating. In the XPS analysis, the sample with STOBA has less percentage of LiF content compare to the sample without STOBA coating. STOBA coating can suppress the decomposition of LiPF6. In a word, the STOBA coating on the electrode not only can restrain the Mn dissolution but also suppress the LiPF6 decomposition. Then, to improve the high-temperature storage performance of Li ion batteries.
Production of Silicon Particles for High-Capacity Anode Material Yielding Outstanding Production Capacity
Authors: Andersen Hanne Flåten , Filtvedt Werner , Mæhlen Jan Petter , Mongstad Trygve Tveiterås , Kirkengen Martin , Holt Arve
Published: February 2020

Silicon is proven to have a great potential as an anode material in lithium-ion batteries due to its high theoretical electrochemical capacity. The standard, commercial graphite anode has a theoretical capacity of less than 400 mAh/g, whereas the silicon anode can potentially deliver a tenfold capacity as a result of multiple Li-ion incorporation in the structure. However, silicon anodes deteriorate quickly during cyclic charging and discharging, rendering them useless in only a few cycles. This has been attributed to stresses induced by the large volume change of the material during cycling. The methods explored in order to overcome these problems such as using lithography, advanced nanotechnology, incorporation of silicon in carbon nanotubes or similar methods are too slow and too expensive for commercial use.

This work presents results from using a silane-based decomposition reactor in order to produce silicon particles with a suitable nanostructure for use in lithium-ion battery anodes. The silane gas is decomposed in a controlled environment at a temperature of 500-600 °C. The current pilot reactor has demonstrated production of up to 350 g/hour in an easily up-scalable lab version. Particles of diameter ranging from 50 nm and up to 500 nm have been produced with relatively narrow size distribution. This method may produce both amorphous and crystalline particles and the surface of the particles can be terminated by hydrogen or other elements if desired.

The silicon particles were mixed with an organic binder in an aqueous slurry and coated on a Cu-foil, The electrochemical performance was tested with CR-2032 coin cells. In the course of the presented work studies of cyclic voltammetry, cycling stability (Figure 1), voltage profiles and electrochemical impedance were performed. Besides electrochemical methods, SEM (Figure 2), XRD, ICP-MS and particle size distribution measurements were implemented. The silicon particles achieved a high capacity, relatively good stability, as well as a high yield and production capacity. Further developments on the silicon particles, such as doping of Si and in-line surface coating, are feasible.
Studies of Si-Fe-C Electrode Materials Prepared By Combinatorial Sputter Deposition
Authors: Al-Maghrabi M A , Dahn Jeff , Dunlap Richard A
Published: February 2020

Introduction

Based on our previous studies (e.g. [1]) and other work [2], it is our opinion that silicon-based amorphous alloys are promising for use as a negative electrode. This is due to the fact that the volume expansion of amorphous silicon (a-Si) upon Li insertion is homogeneous and causes less pulverization as compared to the crystalline material. In addition to the homogenous expansion, the two-phase regions are inhibited once a-Si is used.

Herein, a combinatorial study, on Si-Fe-C sputtered films covering a wide range of compositions is presented. The intention is to study the effect of both Fe and C within the electrode on the electrochemical performance. Carbon was added in the hope that some carbon would remain “free” and could transport intercalated Li effectively to the interior of the particles, whereas iron can form an inactive matrix that reduces the overall volume expansion.

Experimental

Four combinatorial libraries in the Si-Fe-C system were produced using a Corona Vacuum Coaters model V3-T multi-target sputtering system described in [3]. Different targets, two inches in diameter, were used: a Si target, an Fe target and a C target. The targets and a plasma scrubber were mounted on magnetrons. The desired deposition profile was be achieved by using different stationary masks placed over the targets. Figure 1 summarizes the produced compositions.

X-ray diffraction was used to study the structure of these libraries and Mossbauer spectroscopy was employed to probe the atomic environment. Cyclic voltammetry measurements were performed using a multichannel pseudopotentiostat to study the behavior of these materials as negative electrodes for Li-ion batteries

Results and Discussion

Structural Studies:

X-ray patterns obtained from all compositions produced in this study were amorphous or nanostructured and no Bragg peaks indicative of any crystalline phases.

In order to understand the microstructure, as XRD measurements provide little detailed structural information, room temperature Mössbauer spectroscopy was performed on two libraries denoted by solid triangles and circles. The formation of Si-Fe phases were evident.

Electrochemical Analysis:

Figure 1(b) shows the potential versus capacity of the library denoted by the solid circles in Figure 1(a). Data for 64 electrode material are shown. Our combinatorial measurement setup allows for a simultaneous and rapid measurement. The impact of adding iron and carbon on the resulting capacity is illustrated clearly in Figure 1(b).

Through a combined consideration of Mössbauer effect measurements and electrochemical data, the formation of nanoscale regions of inactive Si-Fe and SiC phases was evident.
Organic Electrode Materials, a New Opportunity for Low Cost and High Power Lithium Battery?
Authors: Gutel Thibaut , Bataillé Sonia , Solan Sébastien , Maurel Vincent , Picard Lionel , Chapuis-Rey Marlene
Published: February 2020

Nowadays electrodes of lithium batteries are mainly constituted by inorganic compounds based on transition metals such as cobalt, nickel or manganese. Although their performances are satisfying, these materials present several important drawbacks. Indeed these compounds are expensive because they are prepared due to energy-consuming techniques from rare mineral precursors. Moreover, some metals are toxic and often hard to recycle. Eventually their reactivity leads to safety issues in abusive conditions.

Organic compounds such as nitroxide based polymers offer a cost-effective and environmental friendly alternative to conventional active materials for high power batteries.1,2Interestingly these polymers can be prepared from low cost precursors using classical organic and polymer chemistry techniques. Moreover these compounds are easy to recycle or reuse at their end of life. But until now, their use in electrodes is still challenging due to their solubility in common electrolytes and their very low electronic conductivity.

Our work is focused on the synthesis and the grafting of nitroxide radical on a polymer backbone to prepare poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-ylmethacrylate) [PTMA]. Various functional crosslinker have been introduced in order to decrease the solubility and improve the ionic conductivity of these organic materials. These polymers have been fully characterized by Gel Permeation Chromatography, UV spectroscopy and Electron Spin Resonance. Electrolytes compositions have also been optimized in order to prevent the active materials from leaching into the solvent of electrolytes during cycling. In addition, our development of specific formulation allows us to implement these types of materials in electrodes of lithium batteries and some impressive electrochemical performances, especially at high C-rate, have been obtained.

This work is part of the ROPAS project and has been sponsored by the 7thframework of the EC.

1) Nakahara, Chem. Phys. Lett., 2002, 359, 351-354

2) Nishide, Electrochimica Acta, 2004, 50, 827-831
Nanostructured Porous Silicon - Carbon Anodes for Lithium-Ion Batteries: Two Novel Approaches
Authors: Biserni Erika , Xie Ming , Brescia Rosaria , Scarpellini Alice , Hashempour Mazdak , Mohaved Pooria , Bestetti Massimiliano , Li Bassi Andrea , Bruno Paola
Published: February 2020

Silicon-based electrodes for Li-ion batteries (LIB) have recently attracted much attention because of their high theoretical capacity (~4000 mAh/g) and low average voltage (0.2 V) versus Li. However, the large volume change (~300%) due to Li-Si alloy formation results in poor cycling performance due to mechanical cracking and pulverization. It is believed that nanostructuring can help alleviate the effects of volume change and lead to improved cycling behaviour.

In this work, two novel approaches for composite Si-C anodes for lithium ion microbatteries are presented, based on the deposition of nanostructured porous Si films by Pulsed Laser Deposition (PLD) at room temperature and its coupling to a C layer.

In detail, the one approach is based on covering the as-deposited PLD porous Si films by a disordered graphitic C layer deposited by CVD that promotes the formation of a stable solid electrolyte interphase (SEI) layer, which is a critical step for an effective use of Si in LIB. In addition, the annealing effect induced by the CVD process on the anode is thought to be beneficial for its stability.

In the second approach, nanostructured Si is deposited by PLD on a foil made of carbon nanotubes (CNTs) that acts also as a current collector, thus making the underlying standard copper collector unnecessary. This dramatically reduces the thickness of the overall electrode, thus addressing the requirements for application in innovative microbatteries.

Introducing voids at the nanoscale in the Si film by nanostructuring is meant to accommodate the large volume expansion associated with silicon lithiation with no losses in film continuity (in contrast, for example, with films made of Si nanoparticles), while C is well known to be the standard material for LIB anodes for its good cycle life and capability of forming stable SEI layer with commonly used electrolytes. Moreover, the as-deposited Si film exhibits an amorphous structure in high-resolution TEM (HRTEM) and this avoids its amorphization during the first cycles, turning into lower internal mechanical stresses. Structure and morphology of the C-coated porous silicon samples have been widely investigated by suitable microscopic and spectroscopic techniques and their electrochemical behaviour characterized for different current densities.

With CVD carbon coating, porous silicon promisingly performs in a very stable way, showing areal capacity of ~175µAh/cm2 at 54 µA/cm2, and no decay for at least 1000 cycles.

On the other hand, also porous nanostructured silicon deposited on CNTs performs promisingly, showing areal capacity of ~150µAh/cm2 at 1080µA/cm2 with no decay for at 1000 cycles.
Addressing the Limitations of Layered LiMO2 Electrodes: Structural, Compositional and Electrochemical Control of Integrated ‘Layered-Layered-Spinel’ Cathode Structures
Authors: Thackeray Michael M. , Croy Jason R. , Long Brandon R.
Published: February 2020

Lithium- and manganese rich xLi2MnO3•(1-x)LiMO2 composite structures (M=Mn, Ni, Co) are currently one of the most promising classes of cathode materials for advanced Li-ion batteries. When charged below 4.3 V, and when used in low concentration (typically 0.03<x<0.1), the electrochemically inactive Li2MnO3 component acts as a structural stabilizer to enable modest improvements in electrochemical properties. When higher concentrations of Li2MnO3 are embedded in the matrix (typically 0.3<x<0.5), and when the cells are electrochemically-activated above 4.5 V, significantly higher capacities (250 mAh/g or more) can be achieved. Unfortunately, these high capacity electrode structures are unstable when charged repeatedly to such a high cell voltage. On cycling, the transition metals (M) migrate into the lithium layers; this migration leads to hysteresis, voltage fade, rate impairment and energy inefficiency - despite the retention of electrode capacity. We have addressed these limitations by strategically introducing a small amount of LiM2O4 spinel (M=Mn, Ni, Co) to form ‘layered-layered-spinel’ composite structures. The advantage of this approach is that the M cations of the spinel component occupy alternate layers of an oxygen array, which is structurally compatible with the LiMO2 component, in a 3:1 ratio, thereby imparting stability to the parent ‘layered-layered’ structure. This presentation will provide our recent results in tailoring and improving the structural, compositional and electrochemical properties of structurally-integrated electrode materials that mitigate the voltage fade phenomenon and energy decay of lithium cells.
New Fluorinated Separators for High Power Lithium-Ion Batteries
Authors: De Giorgio Francesca , Arbizzani Catia , Bolloli Marco , Sanchez Jean-Yves , Mastragostino Marina
Published: February 2020

The development of high power Li-ion batteries is of great relevance for hybrid electric vehicles (HEVs) technology. Electrochemical performance of high voltage cells operating with new fluorinated separators and ethylene carbonate - dimethyl carbonate 1M LiPF6 electrolyte with additives was evaluated according to the FreedomCAR DOE protocols to simulate the dynamic functioning of batteries in plug-in HEVs. The results compared to those of cells with commercial separators evidence the beneficial impact of the new fluorinated separators.

Acknowledgments

Work partially funded by the European FP7 (AMELIE Project n.265910). AMELIE Partners CEA, KNUTD and SOLVAY are acknowledged for providing some cell components and for useful discussions.
In-Situ SEM Study on Lithium Oxygen Battery
Authors: Zheng Hao , Xiao Dongdong , Li Xing , Liu Yali , Gu Lin , Wei Xianlong , Hu Yongsheng , Chen Qing , Wu Yang , Wang Jiaping , Jiang Kaili , Li Hong
Published: February 2020

Rechargeable nonaqueous lithium-oxygen batteries have attracted wide attention recently due to its high theoretical energy density. Numerous challenges hinder its practical applications, including low round-trip efficiency, poor rate capability, cycle life on the side of the oxygen electrode, safety issue at lithium side, suitable and stable electrolytes. Among them, the reaction kinetics (ORR and OER) and the transport kinetics (ion transport and electron transport) are essential problems. Great efforts have been paid on fundamental understanding on the morphology, structure and composition of the products under various discharging and charging conditions. Obviously, direct in-situ investigation on the products during ORR and OER processes are desirable. Recently, a facile micro-scale solid state lithium-oxygen battery has been constructed in the environmental scanning electron microscope (ESEM). Based on the design, direct visualization of discharge and charge process of the lithium-oxygen battery has been achieved. Different discharge product morphology has been observed including sphere, conformal films and toroids. And the particles with the size up to 1.5 mm are formed upon discharge, while upon charge, the decomposition initiates at their surface and continues along certain direction. This new findings indicates that the transport kinetics of the electron and lithium ion seem faster on the surface than in the bulk of Li2O2, and the growth and decomposition process of Li2O2is supposed to be anisotropic.

Acknowledgement: Financial support from CAS project "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA01020304) and National project 973 (2014CB932300,2012CB932900) are appreciated.
Role of the Lithium Salt in the Performance of Lithium–Oxygen Batteries: A Comparative Study
Authors: Elia Giuseppe Antonio , Park Jin-Bum , Sun Y-K. , Scrosati Bruno , Hassoun Jusef
Published: February 2020

Due to its high energy density, largely exceeding that of conventional lithium-ion batteries,[1–2] the Li/O2 battery is presently considered as a very promising energy storage system. However, the practical development of this battery is still hindered by several issues, such as: 1) the limited cycle number, affecting its life; 2) the high charge–discharge polarization, resulting in low energy efficiency, and 3) the occurrence of side processes due to moisture and carbon dioxide contamination that preventing its use in open air.

The choice of solvent and of electrolyte salt is expected to play a key role in influencing the cell behavior. To further investigate this important aspect, in this work we have examined the response of a Li/O2 cell using a tetraethylene glycol dimethyl ether electrolyte solutions, with four different salts, that is, LiPF6, LiClO4, LiCF3SO3, LiN(SO2CF3)2. This comparative study demonstrates that LiCF3SO3 salt is the best choice for assuring low cell polarization [3].

[1] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287 –3295.

[2] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193– 2203.

[3] Giuseppe Antonio Elia, Jin-Bum Park, Yang-Kook Sun, Bruno Scrosati, Jusef Hassoun, ChemElectroChem, DOI: 10.1002/celc.201300160.
Alternative Anode Materials for a Highly Stable Lithium Sulfur Battery
Authors: Brückner Jan , Thieme Sören , Althues Holger , Kaskel Stefan
Published: February 2020

The lithium-sulfur battery system is expected to achieve more than double the gravimetrical energy density as state-of-the-art lithium-ion systems. At the same time the material costs can be significantly decreased due to the abundance and low price of sulfur.

What has kept the lithium-sulfur battery from commercialization is its low cycle stability of the system. In our work we demonstrate that the main problem is the metallic lithium anode, which is currently used in most of the publications. The aprotic solvent molecules of the electrolyte are instable versus lithium. When a low amount of electrolyte is used, the cell runs dry and reversible cycling is limited to less than 200 cycles.

Using hard carbon anodes we are able to demonstrate that prolonged, reversible cycling can be achieved for more than 1000 cycles. This system enables balanced lithium-sulfur full-cells with a lithium excess of only 10% and a low amount of electrolyte. The sulfur utilization can be increased to 1470 mAh g-1
sulfur (720 mAh g−1
cathode) by tuning the porosity of the cathode.[1] Our current generation hard carbon anodes achieve a stable areal capacity of 3 mAh cm-2 enabling a combination with high capacity cathodes. Dry processed sulfur cathodes exhibiting an areal loading of 2.5 to 3 mgsulfur cm-2and sulfur mass loading in the cathode of 68 wt% (including carbon matrix, conductive additive and binder) were applied and resulting full cell results will be discussed.

In addition the stable hard carbon anodes can be used to investigate degradation mechanisms in the lithium sulfur battery system. We present results that point toward the fact that nanometer-sized carbon host materials on the cathode side may suffer from increased mechanical degradation. In contrast micrometer-sized porous particles exhibit outstanding cycling performance.

Finally new approaches to transfer these results to high capacity anodes, based on Si/C composites will be discussed.

FIGURE1

Fig. 1: Cycle stability for a metallic lithium and all-carbon anode versus the same carbon-sulfur cathode at 836 mA g-1
sulfurand a limited amount of electrolyte.

[1] J. Brückner et al., Adv. Funct. Mater., 2013. DOI: 10.1002/adfm.201302169.