bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparaison of Electrochemical Performances of Al Doped ZnO/Graphene Composites As Anode Materials for Lithium Ion Batteries
Authors: Benabdallah Omar , Edfouf Zineb , Lallaoui Abdelfettah , Abd-lefdil Mohammed , Saadoune Ismael , Cherkaoui El Moursli Fouzia
Published: February 2020

Recently, many efforts have been deployed to develop new electrode materials for lithium ion batteries (LIBs) in order to meet the growing demand for higher energy density and stronger cyclic stability. Among these materials, zinc oxide (ZnO) as anode has attracted a particular attention due to the natural abundance, low cost, facile preparation and chemical stability. Besides, it has a theoretical capacity of 987 mAh/g, much higher than that of the conventional graphite anode (370 mAh/g). However, ZnO suffers from large volume variations during charge/discharge processes resulting on a severe capacity degradation and reduced cycle life  [1]. To overcome these limitations, metal doping and composite synthesis with highly conductive matrix such as graphene have been used to improve the electrochemical performances of ZnO anode [2,3].

In this study, zinc oxide (ZnO), ZnO/Graphene composite (ZnO/G), aluminium doped ZnO (AZO) and AZO/Graphene composites (AZO/G) were prepared by sol gel method and utilized as anode material for lithium-ion batteries. Samples were characterized by several methods such as X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron spectroscopy (SEM), and transmission electron microscopy (TEM). Electrochemical properties were investigated by cyclic voltammetry and galvanostatic cycling tests.

The effect on the ZnO structure by aluminium doping with different concentrations is observed in the figure attached. This results in an advanced performance with reversible lithium storage capacities compared to the pure ZnO. Moreover, to improve its electrochemical performances, AZO was uniformly dispersed on graphene sheets and the electrochemical properties exhibit higher reversible capacities, better cycle performances and rate capabilities than ZnO, ZnO/G and AZO. The higher performances of this composite may be attributed to the graphene encapsulation, which enhances the electrical conductivity, avoids the aggregation and stabilizes the structure of AZO nanoparticles during cycling.

This communication will compare results obtained from the four samples and evidence the effect of aluminium and graphene added to ZnO anode material.  

References

[1] J.P. Liu, Y.Y. Li, R.M. Ding, J. Jiang, Y.Y. Hu, X.X. Ji, Q.B. Chi, Z.H. Zhu, X.T. Huang, J. Phys. Chem. C 113 (2009) 5336-5339. 

[2] G.L. Xu, Y. Li, T. Ma, Y. Ren, H.H. Wang, L. Wang, J. Wen, D. Miller, K. Amine, Z. Chen, PEDOT-PSS coated ZnOC hierarchical porous nanorods as ultralong-life anode material for lithium ion batteries, Nano Energy, 18 (2015) 253–264.

[3] L. Zhang, J. Zhang, Y. Liu, S. Guo, Effect of aluminium doping amount on the electrochemical properties of ZnO nanoparticles as anode for lithium ion batteries, Micro & Nano Letters, IET, 10 (2015) 217-219.

Figure 1
Research and Development of High Density Spherical Electrode Materials for Lithium Ion Batteries
Authors: Gao Jian , Li Jianjun , He Xiangming
Published: February 2020

The spherical electrode materials usually exhibit some outstanding advantages, such as high pile-density, high capacity density, easily modified and excellent manufacturing performance, and so on. Synthesis of spherical materials is expected as an important direction for lithium ion batteries. This paper reviews two approaches to the preparation of active electrode materials by controlled crystallization process and sol-gel process. The powders prepared by these two methods are spherical shape, dispersivity, good fluidity and high tap density. Recent work on the typical spherical materials of LiCoO2, LiNi0.8Co0.2O2, LiMn2O4, LiNixCoyMnzO2, LiMPO4, Li1+xV3O8, Li4Ti5O12 and their modification derivatives for rechargeable batteries is provided. The prospective application of the spherical cathode materials is also reviewed.
Reversible Li Insertion Studies on V4O3(PO4)3 As High Energy Storage Material for Li-Ion Battery Applications
Authors: Satyanarayana Maddukuri , Rao R.S , Varadaraju U.V , Pralongb Valerie
Published: February 2020

Lithium containing metal phosphate  LiFePO4, LiMnPO4, Li3V2(PO4)3 etc. were explored as a thermally stable electrode materials results from bonding of oxygen to phosphorous stabilizes the structure from oxygen evolution contradict to layered transition metal oxides at high charge voltages. Li2FeP2O7 and Li2MnP2O7 were explored for 2-electrons transfer at high voltage region. Lipscombite related family of Fe1.37(PO4)(OH) and Fe1.19(PO4)(OH)0.57(H2O)0.43 have been studied for lithium batteries by yanning song et al., which shows reversible capacity of 150 and 100 mAh/g respectively, at current density of 0.5 mA/cm2. In the Present study, we synthesized crystalline orthorhombic V4O3(PO4)3phase related to libscombite/lazulite structure family  by solid state reaction method. Reversible Li- insertion studies were performed on this phase in different voltage windows using galvanostatic and cyclic voltammetry unit.

Electrochemical insertion of lithium into V4O3(PO4)3 versus lithium metal as reference electrode was studied. 5.8 Li ions intercalation/f.u. and 4.2 Li ions de-intercalated/f.u. are obtained for 1st cycle with 3.9 Li ions reversible de-intercalation or intercalation/f.u. (195 mAh/g) up to 20 cycles at C/5 rate in the voltage window of 1 – 4 V.  In the voltage range of 0.5 – 4 V at C/3 rate reveals 9.8 Li ions intercalation/f.u. and 6.8 Li ions de-intercalated/f.u.  Ex-situ diffraction data conducted on discharged and charged electrode material in the voltage range of 1 – 4 and 0.5 – 4 V vs. Li+/Li indicates that phase change occurred after interaction of 2.5 lithium ions per formula unit which is corresponding to initial discharge voltage slope plateau obtained at 2.4 V vs. Li+/Li. On further interaction and de-interaction of lithium ions solid solution behaviour is observed. The obtained results will be presented in the presentation.
Applications of Calorimetry to Safety and Performance Testing of Lithium Batteries
Authors: Rachford Jeffrey , Montgomery Danny
Published: February 2020

The poster gives a brief oversight into several key areas of application of calorimetry in relation to safety and performance testing of batteries and modules.

This testing results presented specifically apply to secondary lithium-based cells, which due to their high energy density provide the best solution to electrical energy storage in electric vehicle and other high-demand applications.

Performance testing examines the thermal response of the battery while charging and discharging, as well as finding the fundamental thermal property of average heat capacity which can be used in computer modelling. Performance testing can also help establish the operational limits of the battery, such as minimum and maximum operating temperatures, charging rates or battery life.

Safety testing involves taking the battery beyond these safe operating limits and introducing conditions that will prevent further operation of the battery due to damage. The types of abuse are often based on standard protocols and are those that a battery might rarely be exposed to in the event of damage or system failure.

These abuse tests can be further divided depending on the type of abuse; physical such as crushing, piercing etc, electrical such as overcharging or short circuiting, or thermal, which is the “original” ARC method of increasing the temperature in steps until self-heating of the sample occurs.
Effect on Electrochemical Property of LiNi1/3Co1/3Mn1/3O2 By AlPO4 Nano-Coating
Authors: Li Jianjun , Gao Jian , Wang Li , He Xiangming
Published: February 2020

The performance of LiNi1/3Co1/3Mn1/3O2 cathode material is improved by AlPO4 nano-coating. AlPO4-coated LiNi1/3Co1/3Mn1/3O2 is obtained by suspension solution of nano AlPO4. Related characters are investigated by X-ray powder diffraction (XRD), scanning electron microscope imaging (SEM), transmission electron microscope imaging (TEM) and charge-discharge cycling test. The results show that the coating do not change the structure of LiNi1/3Co1/3Mn1/3O2, its surfaces are covered uniformly by nano AlPO4, and the thickness of coating layer is about 4nm. To the electrochemical performance, AlPO4-coated LiNi1/3Co1/3Mn1/3O2 is markedly improved capacity retention compared to pristine material upon cycling at 3.0- 4.5 V. Higher is the weight proportion of coating, better is the performance. However, high weight proportion of coating reduces the capacity. 0.2wt% coating is selected, because it not only improve capacity retention upon cycling at 3-4.5V, but also retain the best capacity of positive material.
NaxVxTi1-XO2 (x = 0.6 - 1.0) Phases for Na-Ion Battery Electrode Materials
Authors: Fielden Ryan I , Cole Laura , Obrovac Mark N
Published: February 2020

Introduction

Due to the high cost of lithium-ion batteries and potential limited accessibility of lithium reserves, sodium-ion batteries have emerged as an alternate battery chemistry [1].  Sodium-ion batteries trade lithium ions for sodium ions while retaining the rocking chair like mechanism for electrochemical transport.  The advantage of using sodium instead of lithium is its low cost, which is largely due to its widespread availability.  Titanates have been investigated for use as anode materials in Na and Li cells.  Recently and new family of titanates, NaxMyTi1-yO2 (M = Li, Ni, Co, or Cr), have been reported.  These materials show remarkable low voltage cycling stability [2-5]. Herein another member of this family, namely the NaxVxTi1-xO2 (0.6 ≤ x ≤ 1) series, was studied for use as an anode material in sodium-ion batteries. 

Experimental

Samples were synthesized via high energy ball milling of Na2CO3, V2O3, and TiO2 then heating pellets to 950 °C for 6 hours in an argon/H2:95/5 atmosphere. A 10 % Na excess was added due to the volatility of Na at these elevated temperatures.  Samples for X-ray diffraction measurement were loaded under argon into an air-tight sample holder with an aluminized Mylar window.  Electrodes comprising NaxVxTi1-xO2, carbon black and PVDF binder were cast using NMP as a solvent and dried at 120°C.  Electrodes were cycled in 2325 coin type cells at a rate of C/10 (assuming a 100 mAh/g capacity) using Na metal counter/reference electrodes and 1M NaPF6 in PC electrolyte. 

Results and Discussion

Figure 1 shows the XRD patterns of the as synthesized NaxVxTi1-xO2 (0.6 ≤ x ≤ 1) materials.  They all have layered type structures.  Electrochemical measurements showed that these materials can intercalate Na in bulk particles at low voltages and with very low hysteresis.  Figure 2 shows the voltage profile of the x = 0.66 material for the first cycle and a half.  These materials have substantial low voltage capacity and remarkably low hysteresis, as shown in Figure 2.  As such they are promising candidates for Na-ion battery negative electrodes.   Structural changes and stability during cycling, for different cut-off voltages, will be discussed.

References:

[1] D. Kundu et al., Angew. Chem. Int. Ed. Engl., 54 (2015) 3431-3448.

[2] R. Fielden, M.N. Obrovac, J. Electrochem. Soc., 161 (2014) A1158-A1163.

[3] Y. Wang et al., Nature Comm., 6 (2015) 6954-6962.

[4] H. Yu et al., Angew. Chem. Int. Ed. Engl., 53 (2014) 8963-8969.

[5] Y. Wang et al., Nature Comm., 4 (2013) 1-7.

Figure 1
Mxene: Novel Negative Electrode Materials for Sodium-Ion Batteries
Authors: Okubo Masashi , Wang Xianfen , Kajiyama Satoshi , Iinuma Hiroki , Hosono Eiji , Oro Shinji , Moriguchi Isamu , Yamada Atsuo
Published: February 2020

Recently, urgent concerns over lithium resources have focused attention on Na-ion batteries owing to the abundance and low cost of sodium. However, the presently-considered negative-electrode materials for Na-ion batteries are Na-ion intercalation (carbon compounds, metal oxides and metal sulfides), alloying (phosphorus and tin) or conversion materials (metal oxides and metal sulfides), the energy and power densities of which are not satisfactory if the Na-ion batteries were to outperform the state-of-the-art Li-ion batteries. Hence, exploration for novel negative electrode materials of sodium system is primarily important.

 We have targeted MXenes as potential electrodes for sodium system. MXenes have been developed as a novel family of nanosheet compounds, which are chemically derived from layered Mn

+1
AXn
or MAX phases (M: early transition metal, A: A-group element, and X: C and/or N). As the MXene has both a high electrical conductivity and interlayer porous space, its application to Na-ion battery negative electrodes holds great promise.

 In this presentation, we report on Ti
n

+1C
n
T
x
as negative electrode materials for Na-ion batteries. Ti
n

+1C
n
T
x
consists of abundant and low-cost elements, enabling fabrication of sustainable energy sources. We demonstrate that Ti2CT
x
exhibits a reversible capacity of 175 mAh/g at the average potential of 1.3 V vs. Na/Na+. Furthermore, the prototype full cell consisting of alluaudite Na2Fe2(SO4)3-Ti2CT
x
delivers a high specific energy of 260 Wh/kg at a high specific power of 1.4 kW/kg based on the weight of Ti2CT
x
. Using various experimental and theoretical analyses, we clarify that the Ti
n

+1C
n
T
x
electrodes allow Na-ion batteries to be liberated from the trade-off between high energy and high power.

[Reference]

X. Wang, et al., M. Okubo, & A. Yamada, Nat. Commun., 2015, 6, 6544.

Figure 1
The Influence of Carbon Cathode in Rechargeable Li-O2 Batteries Based on a LiNO3-Litfsi/DMSO Electrolytes
Authors: Yoo Eunjoo , Zhou Haoshen
Published: February 2020

Rechargeable Li-O2 batteries have been considered one of the most promising candidates as the power source for electric vehicles due to their extremely high energy density [1,2]. In spite of this great prospect, there are still many obstacles such as the degradation of the electrode, huge polarization, low energy efficiency and poor reversibility [3]. Thus, developing stable and effective cathode catalysts is important as they can be utilized to decrease the polarization and increase the reversibility. Carbon materials are known to advantageous air electrodes for Li-O2 batteries with nonaqueous electrolyte due to their good conductivity and site of reversible electrode reaction. However, the influence of carbon materials on electrochemical performance in Li-O2 batteries is not clear. Furthermore, recent research focused on selecting a combination of lithium salt and electrolytes by challenge in improving the electrochemical performance of Li-O2 batteries. In this study, we select four different kinds of carbon materials such as multi-walled carbon nanotubes (MWCNTs), CMK-3, Graphene nanosheets (GNSs), and KB as air electrodes and further examine their electrochemical performance in Li-O2 batteries with 0.7 M LiNO3-0.3 M LiTFSI/DMSO electrolytes.

We find that the Li-O2 cell with a MWCNTs electrode in a 0.7 M LiNO3-0.3 M LiTFSI/ DMSO electrolyte demonstrates good rate performance and cycle stability comparison with other carbon electrodes. The result shows that the Li-O2 cell based on MWCNTs electrodes with a cut-off capacity of 1000 mAg-1 at 500 mAg-1 can undergo around 90 cycles without obvious capacity loss. Even when the discharge depth is increased to 2000 mAhg-1, stable cycling is maintained for 45 cycles with a charge potential below 4.0 V vs. Li/Li+. Moreover, when the rate performance of Li-O2 cell with MWCNTs electrodes is examined at different current densities from 200, 400, 500, and 1000 mAg-1 with a cut-off capacity of 2000 mAhg-1, interestingly, the discharge voltage is not drastically increased even the current density is 1000 mAg-1. And then, the chare voltage remains at around 3.85 V, which is similar to the current density of 200 mAg-1 (about 3.82 V). Therefore, these results demonstrate that the MWCNTs maintain excellent activity and stability of catalysts toward the reversible formation-decomposition of Li2O2.

Reference

[1] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J. M. Tarascon, Nat. Mater. 2012, 11, 172– 172

[2] J. Lu, L. Li, J.-B. Park, Y.-K. Sun, F. Wu, K. Amine, Chem. Rev. 2014, 114, 5611 –

5640.

[3] L. Grande, E. Paillard, J. Hassoun, J.-B. Park, Y.-J. Lee, Y.-K. Sun, S. Passerini,
Bifunctional Catalytic Activity of Sea Urchin Shaped α–MnO2/RuO2 Nanostructures on ORR and OER for Lithium Oxygen Battery
Authors: Jang HoSaeng , Zahoor Awan , Lee Yun Sung , Nahm Kee Suk
Published: February 2020

Li–O2 battery offers a dramatic increase in theoretical energy density relative to Li–ion cells, opening up the possibility of electric vehicles and renewable high energy systems. However, the sluggish kinetics at air cathode during discharge and charge processes requires the development of a promising bifunctional electrocatalysts to simultaneously improve the oxygen reduction and oxidation (ORR and OER) kinetics, resulting in increased reversibility of the battery. In this work, three dimensional (3D) α–MnO2/RuO2 mixed oxides at different ratios were synthesized using a simple hydrothermal method. The 3D mixed oxides were designed to be applied as suitable bifunctional electrocatalysts for Li–O2 batteries. The morphology of the mixed oxides changed from sea urchin shaped nanostructures to nanospheres with the increase of RuO2 content in the mixed oxides. The bifunctional catalytic properties were analyzed using oxygen reduction and evolution reactions (ORR and OER) in a rotating ring disc electrode system. It was found that α–MnO2 and RuO2 significantly served as ORR and OER catalysts, respectively, confirming that the mixed oxide is a suitable bifunctional catalyst for Li–O2 battery. Among the four different α–MnO2/RuO2 composition ratios, (75:25) appeared to be the optimum ratio for the mixed oxides with superior activity for both ORR and OER. The superior performance of α–MnO2/RuO2 (75:25) could be attributed to its structural and compositional design which aid in the better catalytic performance. When applied in Li–O2 battery system, the (75:25) ratio exhibited excellent performance with a maximum capacity of >8100 mAh g-1 with high columbic efficiency and cyclability.
On the Ambiguous Nature of the Discharge Products in Sodium-Oxygen Batteries: From Theoretical Considerations to Operando XRD Analyses
Authors: Pinedo Ricardo , Bender Conrad L. , Schröder Daniel , Bergner Benjamin J. , Weber Dominik , Adelhelm Philipp , Janek Jürgen
Published: February 2020

Rechargeable lithium-oxygen and sodium-oxygen cells are considered as promising systems for next-generation batteries, both scientifically and technologically [1,2]. While the desired cell reaction is clear in the case of non-aqueous Li/O2 batteries (Li2O2 formation), the situation is much less clear in the case of non-aqueous Na/O2 cells. Two discharge products, with almost equal free enthalpy of formation but different number of transferred electrons and completely different kinetics, appear to compete, i.e. sodium superoxide (NaO2, one-electron-transfer) and sodium peroxide (Na2O2, two-electron-transfer) [3]. In spite of the several fundamental studies published until now, the experimental control parameters for the exclusive formation of one or the other phase during discharge are still unknown.

Moreover, under certain conditions, dihydrated sodium peroxide has also been found. The formation of this product has been ascribed to undesired reactions, such as electrolyte degradation [4], which could provide the required water source. However, this hypothesis is not consistent with the results of the group of Nazar, who reported that Na-O2 cells cannot be discharged in absence of water, which acts as a proton source [5]. Consequently, if the proton source could be supplied by the electrolyte, Na-O2 cells with 0 ppm water could be also discharged.

This work tries to summarize and answer the major questions that propel research on Na/O2 cells at the moment. For this purpose, theoretical and thermodynamic considerations, together with operando XRD analyses are presented. In addition, the implications on the electrochemical performance of the different discharged products are also evaluated, shedding some light on the chemistry of these promising systems. Nevertheless, many questions remain open, and their precise answer will help to improve the understanding of further non-aqueous metal-oxygen systems and to propel the research efforts on their cell chemistry.

References

[1]. P. Hartmann et al., Nat. Mat.
2013, 12, 228-232.

[2]. B. Bergner et al. J. Am. Chem. Soc.
2014, 136, 15054-15064.

[3]. C.L Bender et al., Angew. Chem. Int. Ed.
2016, (accepted).

[4]. J. Kim et al. Phys. Chem. Chem. Phys.
2013, 15, 3623-3629.

[5]. C. Xia et al. Nat. Chem.
2015, 7, 496-501.
Sulfur/Multiwalled Carbon Nanotube Composite Cathode for High Performance Lithium/Sulfur Batteries
Authors: Zhang Yongguang , Yin Fuxing
Published: February 2020

Lithium/sulfur batteries have gained intense attention as one of the most promising candidates for high energy density rechargeable batteries due to their high theoretical specific capacity of 1672 mAh g-1 and theoretical energy density of 2600 Wh kg-1 based on cathode materials. In addition, sulfur has the advantages such as low cost, natural abundance, and environmental friendliness. Herein, we report on the preparation of the long-time stabilized MWNT aqueous suspension with the addition of sodium dodecylbenzene sulfonate (SDBS) surfactant, and a well-dispersed sulfur/multiwalled carbon nanotube (S/MWNT) composite synthesis via a simple stirring mixing of the resultant MWNT suspension with commercial nanosized sulfur aqueous suspension. This preparation method based on the suspension mixing possesses the advantages of simplicity and low cost. Homogeneous dispersion and integration of MWNT in the composite results in a porous, highly conductive and mechanically flexible framework with enhanced electronic conductivity and ability to absorb the polysulfides into its porous structure. The cell with this S/MWNT composite cathode demonstrates a high reversibility, resulting in a stable reversible specific discharge capacity of 708 mAh g-1
after 100 cycles at 0.1 C. Furthermore, the S/MWNT composite cathode with sulfur content of 62.5 wt% exhibits a good rate capability with discharge capacities of 946, 780 and 516 mAh g-1 at 0.5, 1 and 1.5 C, respectively.
High Electrochemical Performance of Hirechically Porous MnCo2O4 Microsphere As an Anode Material for Li-Ion Batteries
Authors: Thorat Gaurav M. , Jadhav Harsharaj S. , Seo Jeong Gil
Published: February 2020

Alternative active anode materials for graphite and its electrode designs for lithium ion batteries (LIBs) are under extensive investigation to meet the increasing energy storage demands. The rational design of three-dimensional (3D) hierarchical pore architectures of metal oxides and related hybrids possessing are advantageous to improved electrical conductivity and reduced volume change during charge–discharge processes. Manganese cobaltate (MnCo2O4) is considered as one of the most prospective anode material in LIBs due to its high reversible capacity and structural stability. In this work, hierarchically porous MnCo2O4 microspheres are synthesized via facile hydrothermal and chemical bath deposition methods followed by post –annealing treatment. FE-SEM and TEM analysis reveal that resulting microspheres consists of a smaller secondary nano-particles. Benefited from such mesoporous structure with much higher specific surface area, the LIBs assembled with MnCo2O4 microspheres as anodes material showed high specific capacity and excellent rate capability with superior cycle life. Such excellent electrochemical performance may originate from the reduced particle size and more active interfacial sites in the hierarchical structure. Also, the large volume variation of the anode material by the redox reactions occurs during Li+ insertion- extraction process can be effectively buffered due to the appropriate pore size of MnCo2O4 microspheres and as consequences the microsphere structure has become structurally robust which is important for enhanced electrochemical stability of  anode material. As obtained results indicate that MnCo2O4 is a finer material for Li storage and with the simplicity in synthesis route its mass-production can be easily achievable which makes MnCo2O4 as competent anode material for LIBs. The overall synthesis strategy in this work is simple, cost effective and inspires for the rational design of hierarchical porous structures with enhanced properties for other spinel transition metal oxide on the nanoscale, where these spinel structures may present potential applications in the field of energy storage. This work was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant number: NRF-2013R1A1A2060638 and No. 2009-0093816).
The Synthesis of Micrometer-Sized Spherical Li4Ti5O12/Reduced Graphene Oxide for High-Performance Lithium Ion Batteries
Authors: Kim Myeong-Seong , Lee Geon-Woo , Kim Kwang-Bum
Published: February 2020

With the expanding the market of lithium-ion battery (LIBs) from portable electronic devices to electric vehicles and energy storage system (EES), the improvement on their energy density, power density, safety, and cost should be highly necessary. Among the promising anoode materials for LIB, Li4Ti5O12 has various advantages, such as high theoretical capacity (175 mAh g-1), good Li-ion intercalation reversibility, and extremely small structural changes during charge–discharge cycling.

Despite these advantages, Li4Ti5O12 is limited for use of LIBs due to its low electronic conductivity (10-13 S cm-1), which leads to poor rate capabiltiy.1 Several effective ways to improve the rate capability of Li4Ti5O12 have been reported, including reduction of the particle size to the nanoscale, doping Li, Ti, or O sites with small amounts of metal or nonmetal ions, surface modification or carbon coating, and its incorporation into composites with carbonaceous materials.2

Among the various carbonaceous materials, reduced graphene oxide (RGO) or graphene nanosheets has attracted considerable interest as electrode materials for electrochemical energy storage because of their unique properties such as high electronic conductivity, large surface area, and good mechanical properties. Some recent studies have demonstrated the excellent rate capability and cycle stability of Li4Ti5O12/RGO nanocomposites.3 However, previously reported Li4Ti5O12/RGO nanocomposites mostly have 2-dimension morphologies with low tap density.3 The 2-dimentional Li4Ti5O12/RGO nanocomposites are not suitable for commercial use because their low tap density limits the volumetric energy density. Therefore, a simple and facile synthesis of micrometer-sized spherical Li4Ti5O12/RGO composites with a high tap density and superior rate capability is highly desirable. 

In this study, we report one-pot synthesis of micrometer-sized spherical Li4Ti5O12/RGO with high tap density, wherein the initial Li-Ti-O/RGO precursor is fabricated by the spray drying method in the presence of all precursors in a solution. Upon subsequent heat treatment, phase-pure micrometer-sized spherical Li4Ti5O12/RGO with high tap density was successfully synthesized. More detailed on the synthetic procedure, morpology, electrochemical and structural properties of micrometer-sized spherical Li4Ti5O12/RGO will be presented at the meeting.

References

[1] S. G. Doo et al, J. Am. Chem. Soc., 2008, 130, 14930

[2] N. Ohta et al, Adv. Mater., 2006, 18, 2226

[3] H. K. Kim et al, Electrochem. Commun., 2010, 12, 1768
Thermodynamics and Kinetics of Li Extraction from Li-Rich Layered Manganese Oxide Cathodes
Authors: Chen Hungru , Islam M. Saiful
Published: February 2020

Li-rich layered oxides Li1+xM1-xO2 (0<x<0.33), where M=Co, Mn, Ni, have emerged as promising cathode materials, because they can deliver much higher capacities (> 250 mAh/g) than the conventional LiCoO2 cathode. Important issues relate to what is the origin of the electrochemical activity and high capacity? In this work, possible charge compensation mechanisms upon lithium extraction from Li2MnO3 are studied by ab-initio density functional theory calculations: (a) Reversible oxidation of bulk O2- to other anion species such as superoxide or peroxide; (b) Loss of lattice oxygen (oxygen evolution). Both thermodynamic (reaction enthalpies and electrochemical potentials) and kinetic (ion migration) aspects are investigated.
Evolution of Nano-Crystalline Silicon Anode upon Cycling Probed By E
x Situ Raman Spectroscopy and Operando Synchrotron X-Ray Diffraction
Authors: Pavlenko Ekaterina , Quazuguel Lucille , Boniface Maxime , Tardif Samuel , Rieutord François , Marechal Manuel , Micha Jean-Sébastien , Mareau Vincent , Gonon Laurent , Lyonnard Sandrine
Published: February 2020

Silicon is being considered as one of the most promising anode materials for next generation lithium-ion batteries due to its high theoretical capacity (3580 mA h g-1 at room temperature) (1). Upon charging, Si and Li react via an alloying process with a sharp interphase separating the growing LixSi amorphous phase from the pristine crystalline Si. In case of spherical particles this leads to a core-shell structure captured in Figure1a. The alloying process leads to an enormous volume expansion of Si resulting in cracking of the electrode material and rapid fading of its performance that impedes the commercialization of Si-based anodes. Nevertheless below a critical particle diameter of 150nm volume expansion does not lead to cracking (2). In order to profit from silicon unique properties, the structural evolution along charging/discharging must be understood.

Using ex situ Raman spectroscopy we observed the gradual transformation of initially crystalline silicon into amorphous one upon cycling. The resulting stresses generated in the crystalline cores of the core-shell structures were probed as well as their evolution along lithiation/delithiation. The changes of the crystalline lattice during the initial cycles were also monitored using operando synchrotron X-ray diffraction (XRD). In addition we were able to further quantify the constrained/unconstrained state of the silicon core. We show that combined ex situ Raman spectroscopy and in situ XRD provide in-depth understanding of the nanoparticles evolution.

Figure
1
. Schematic representation of silicon electrodes: a) Formation of a core-shell structure upon cycling, b) Influence of the laser power on the Raman signal and c) Gradual amorphization of the electrode along cycling 
(All spectra were normalized to the maximum of the c-Si peak)

 1. Obrovac, M. N., and Leif Christensen. "Structural changes in silicon anodes during lithium insertion/extraction." Electrochemical and Solid-State Letters 7.5 (2004): A93-A96.

2. Liu, Xiao Hua, et al. "Size-dependent fracture of silicon nanoparticles during lithiation." Acs Nano 6.2 (2012): 1522-1531.

Figure 1
Study on Phase Transitions of Lithium-Nickel-Manganese Oxide Li1+XNi0.5Mn1.5O4.0 (0 < x < 1) As High-Voltage and High-Capacity Cathode Materials
Authors: Mancini Marilena , Axmann Peter , Gabrielli Giulio , Kinyanjui Michael Kiarie , Golla-Schindler Ute , Kaiser Ute , Wohlfahrt-Mehrens Margret
Published: February 2020

Rising demands for high-energy density Li-ion batteries require the development of new cathode active materials with enhanced specific capacity and energy, increased safety and reduced cost. Currently used high-cost metals, such as cobalt and nickel, need to be replaced with more abundant and less toxic elements.

A Co-free cathode material with high-voltage and high-capacity has been developed in our labs. The lithium‐nickel‐manganese oxide with composition Li1+xNi0.5Mn1.5O4.0 (0<x<0.5) was tailored with respect to morphology, particle size and shape distribution. The particles consist of densely packed nano‐sized primary crystallites and the free‐flowing powder shows a tap‐density of 2.4 g cm-3.

The cathode material shows a specific capacity of about 210 mA h g-1 in the potential window 2.4-4.9 V. The working mechanism involves two distinct voltage plateaus at 4.7 and 2.9 V vs. Li/Li+. Very good cycling stability is obtained for more than 200 cycles in half-cell.

Compared to other high-capacity materials, such as lithium-manganese-rich layered oxides, their spinel integrated variants and the cation disordered materials [1-3], this material does not need an activation cycle; it shows good rate capability and low voltage hysteresis.

In full-cell vs. graphite anode, a stable capacity of 160 mA h g-1 is reached.

For full-cell application no electrochemical pre-treatment or structural activation has to be applied in order to achieve the full capacity; therefore, the material can be directly assembled vs. graphite anode.

Cathode material features will be described, electrochemical performances in half- and full-cell will be presented and the influence of the operating voltage window will be shown. The effects of particle shape, grain architecture and structural features on the electrochemical behavior will be discussed.

Phase transitions in the low-potential region have been studied by HRTEM, EELS and XRD and the involved mechanism will be discussed.

Acknowledgements

This work was supported by the German Federal Ministry of Education and Research (BMBF) in the project Li-EcoSafe (03X4636A).

References

[1] Thackeray, M.M.; Kang, S.-H.; Johnson, C.S.; Vaughey, J.T.; Benedek, R. and Hackney, S.A., J. Mater. Chem., 17 (2007) 3112

[2] Park, S.-H.; Kang, S.-H., Johnson, C.S., Amine, K.; Thackeray, M.M., Electrochem. Comm., 9 (2007) 262

[3] Yabuuchi, N.; Takeuchi, M.; Nakayama, M.; Shiiba, H.; Ogawa, M.; Nakayama, K.; Toshiaki Ohta, T.; Endo, D.; Ozaki, T.; Inamasu, T.; Sato, K.; Komaba, S., PNAS 12 (2015) 7650
Organosilane Cathode Coatings for High-Voltage Lithium Ion Batteries
Authors: Peebles Cameron , He Meinan , Dogan Fulya , Hubaud Aude A. , Vaughey John T. , Liao Chen
Published: February 2020

One of the more promising cathode materials for high-energy high-voltage lithium ion batteries (LIBs) are Ni-rich layered cathode materials such as LiNixMnyCozO2 (where x + y + z = 1). Although these cathode materials are attractive from a high capacity standpoint, they commonly suffer from poor structural stability at highly delithiated (charged) states leading to poor electrochemical performance.1-3 To help aid these issues, surface coatings are becoming a widely adopted method to improve the cycling performance of high-voltage cathode materials. More widely investigated coating materials include oxide coatings (Al2O3, TiO2, etc.)4 while comparatively fewer studies have investigated organic monomer or polymer coatings (PEDOT, polyimide, etc.).5

In this work, the surface of LiNi0.5Mn0.3Co0.2O2 cathode materials were coated with organosilane reagents to investigate their effect on cell electrochemical performance. The impact of the weight percentage of organosilane used and the functionality of the organosilane used will be presented. Characterization of the organosilane coating using XRD, XPS and FTIR confirm the presence of a Si-containing coating. Cycling performance for half cells (Li/ LiNi0.5Mn0.3Co0.2O2) using the organosilane coated cathodes will be shown. In conclusion, a new type of organic coating was utilized on Ni-rich cathode materials and this research explores a new type of coating for high voltage cathodes.

1)      Son, I. H.; Park, J. H.; Kwon, S.; Mun, J. and Choi, J. W. Chem. Mat.
2015, 27, 7370-7379.

2)      Bak, S.-M.; Hu, E.; Zhou, Y.; Yu, X.; Senanayake, S. D.; Cho, S.-J.; Kim, K.-B.; Chung, K. Y.; Yang, X.-Q. and Nam, K.-W. ACS Appl. Mater. Interfaces
2014, 6, 22594-22601.

3)      Lin, F.; Markus, I. M.; Doeff, M. M.; Xin, H. L. Sci. Rep., 2014, 4, 5694.

4)      Xu, S.; Jacobs, R. M.; Nguyen, H. M.; Hao, S.; Mahanthappa, M.; Wolverton, C.; Morgan, D. J. Mater. Chem. A, 2015, 3, 17248.

5)      Zhang, J.; Lu, Q.; Fang, J.; Wang, J.; Yang, J. and NuLi, Y. ACS Appl. Mater. Interfaces
2014, 6, 17965-17973.
Self-Healing Lithium-Based Batteries
Authors: Roumi Farshid
Published: February 2020

We are proposing a novel approach to enable rechargeable lithium metal anode batteries. The scientific merit of our approach is based on the effect of electric field manipulation in the vicinity of the lithium metal on the electrodeposition of lithium metal. We demonstrate how the spatial gradient of the electric field in the cell can be controlled and its effect on the electrodeposition of lithium metal during charging is studied. More than 200 cycles at C-rate in Li-metal- LTO cells with commercial electrolyte is achieved.

For the first time we show that it is possible to control the electric field inside the battery cell with addition of a porous metallic layer in the middle of the cell. The metallic layer significantly reduces the spatial gradient of the electric field, if any shorts reaches this layer. We will discuss how different metallic materials affect the dendrite destiny. Specifically, we show how an aluminum based layer can react with a lithium dendrite, consumes the available energy, and eventually burns out the lithium dendrite, such that the cell can keep functioning as a fresh cell with no indications of a short in its past cycling. Numerical and theoretical studies accompany our experiments to shed life on this interesting physical observation. The approach may give us an understanding of unprecedented methods to enable safe rechargeable lithium metal batteries.

Figure 1
Tailoring Nickel-Rich LiNi0.8Co0.1Mn0.1O2 Cathode Material with LiNi0.
4Co0.
2Mn0.
4O2 Surface Composition
Authors: Shin Youngho , Kahvecioglu Feridun Ozgenur , Krumdick Gregory
Published: February 2020

Nickel-rich cathode material, LiNi0.8Co0.1Mn0.1O2, exhibits high specific capacity of approximately 200 mAh/g-oxide and potential for use in plug-in hybrid electric vehicles. However, significant challenges remain to improve the cycle life and thermal-abuse tolerance of this material. To improve the stability of this material, several researchers have investigated a core-shell approach resulted in a nickel-rich LiNi0.8Co0.1Mn0.1O2 core and a manganese-rich LiNi0.5Mn0.5O2shell for surface stabilization [1]. However, the structural mismatch between the core and shell compositions leads to large void formation at the core-shell interface which triggers a sudden drop in capacity after long-term cycling. To overcome the volume change between the core and shell compositions, concentration gradient shell was investigated [2] and full concentration gradient material was suggested which shows the gradual decrease of nickel concentration and increase of manganese concentration from the centre towards the outer layer of the particle [3].

Even though many researchers showed the promising high energy, long calendar life and excellent abuse tolerance of core-shell, core-concentration gradient shell and full concentration gradient materials by their synthesis optimization, the compared nominal composition of LiNi0.8Co0.1Mn0.1O2 was not well-optimized. Here, we report the optimized synthesis condition of a nominal composition of LiNi0.8Co0.1Mn0.1O2, core-shell and core-concentration gradient shell materials with LiNi0.4Co0.2Mn0.4O2 surface composition. The detailed comparison of the physical and electrochemical properties of the prepared materials will be discussed.

References

Y.-K. Sun, S.-T. Myung, M.H. Kim, J. Prakash and K. Amine, J. Am. Chem. Soc. 127(38), 13411 (2005).

Y.-K. Sun, S.-T. Myung, B.-C. Park, J. Prakash, I. Belharouak and K. Amine, Nature Mater. 8, 320 (2009).

Y.-K. Sun, Z. Chen, H.-J. Noh, D.-J. Lee, H.-G. Jung, Y. Ren, S. Wang, C.S. Yoon, S.-T. Myung and K. Amine, Nature Mater. 11, 942 (2012).
Next-Generation Li[Ni0.8Co0.06Mn0.14]O2 Positive Electrode Material with a Dual Concentration Gradient for High-Energy Li-Ion Batteries
Authors: Park Kang-Joon , Jung Hun-Gi , Sun Yang-Kook , Haro Marta , Vicente Nuria , Bisquert Juan , Garcia-Belmonte Germa
Published: February 2020

To increase the reversible capacity of layered lithium nickel-cobalt-manganese oxide, a Li [Ni0.8Co0.06Mn0.14]O2 positive electrode with a two-sloped full concentration gradient (TSFCG) was successfully synthesized via co-precipitation. The TSFCG maximizes the Ni concentration in the particle core and the Mn concentration on the particle surface. The TSFCG Li[Ni0.8Co0.06Mn0.14]O2 positive electrode showed improved overall electrochemical properties (i.e., reversible capacity, cycle life, and rate capability) and thermal stability compared to a conventional positive electrode (CC) Li [Ni0.8Co0.06Mn0.14]O2 without a concentration gradient. Electrochemical impedance spectroscopy showed that the high stability of the outer surface composition of Li[Ni0.64Co0.06Mn0.30]O2 is responsible for reduction in surface resistance and charge transfer resistance by decreasing the parasitic reaction with the electrolyte. These reduced resistances explain the superior rate capability of TSFCG positive electrodes.
Doped TiNb2O7 with Enhanced Lithium-Ion Storage Performance
Authors: Li Shuang
Published: February 2020

Pure and doped TiNb2O7 nanoparticles were synthesized from niobium ethoxide (Nb(OC2H5)5) and titanium isopropoxide ( C12H28O4Ti). The resulting material has been subjected to systemic structural and property characterization such as X-ray diffracttometry (XRD), scanning and transmission electron microscopies (SEM/TEM), nitrogen sorption isotherms, electrochemical impedance spectrum (EIS), and capacitance measurements. Different ratio materials including TiNb2O7, TiNb1.9O7, Ti09Nb2O7, and Ti0.95Nb2O7 with defects and oxygen vacancy were obtained in this study. Ti0.95Nb2O7 and  TiNb1.9O7 have demonstrated specific capacity much greater than both pure TiNb2O7 and Ti09Nb2O7 counterparties. The relationship between processing condition, micro- and porous structure, electrochemical properties of pure and defective TiNb2O7 electrodes will be discussed.
Polydopamine-Coated Current Collector: Improving the Electrochemical Performance of Si Anode By Raising the Interfacial Adhesion Strength
Authors: Kong Seokhyeon , Cho Inseong , Hwang Suyeon , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

The high theoretical capacity of Si has made it a promising candidate for high energy density and large-scale lithium ion battery (LIB) anode. However, this system exhibits rapid capacity decay and hence poor cycling performance due to huge volume expansion of about 300% when Li-ion inserts into the Si particle during charging. Experimental observations suggest the formation of cracks at the early stages of cycling due to this volume expansion. The continuous mechanical stressing and fracturing of Si particles lead to the pulverization of the electrode and formation of dead Si particles. In particular, dead particles detached from current collector can mainly occur decay of electrochemical performance of lithium ion batteries.[1,2]

  Hence, we tried to improve the interfacial adhesion between the Si electrode layer and the current collector by making a hydrophilic layer on the current collector through polydopamine coating and induce cross-linking of polydopamine (PD) and polyacrylic acid (PAA) binder. The contact angle and the interfacial adhesion between the electrode and the PD coated and bare current collector were analyzed using Phoenix 300 Touch and the Surface And Interfacial Cutting Analysis System(SAICAS), respectively.

  From the SAICAS analysis, the adhesion strength between PD-coated current collector and Si electrode layer was improved comparing to the bare system. (Bare current collector: 0.2455 kN m-1 and PD-coated current collector: 0.3532kN m-1). The PD-coated current collector showed a higher hydrophilicity to the electrolyte than the bare current collector. The cycle performance of the cell was greatly enhanced by the PD coating on the anode current collector. The present studies suggest that, the coating of PD and induced cross-linking of PD and PAA improves the electrochemical performance of the Si anode.

Acknowledgement

  This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea(NRF-2014H1C1A1066977)

 

References

1. J. Choi, M.-H. Ryou, Y. M. LEE, Journal of Power Sources 252 (2014) 138-143

2. J. Choi, K. Kim, M.-H. Ryou, Y. M. LEE ACS Appl. Mater. Interfaces 2015, 7, 14851−14858
Effect of Highly Surface-Roughened Copper Foil on Electrochemical and Adhesion Properties of Silicon Anode
Authors: Cho Inseong , Lee Seonhyeong , Song Kideok , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

Electrically well-contacted state between electrode coating layer and current collector in lithium rechargeable batteries is very important because their insufficient interfacial contact can occur degradation of electrochemical performance.[1] To enhance adhesion property between silicon electrode and copper current collector, in this work, surface-roughened Cu foil (roughness: 4-5μm) is employed as a new current collector. Its physical and electrochemical performances are compared with the commercial smooth Cu foil (roughness: 1-2 μm) for lithium rechargeable batteries. The silicon anode on the surface-roughened Cu foil showed not only higher the adhesion strength, but also improved cycle performance. We verified this issue by measuring adhesion force during the peeling test (Versatile Peel Analyzer, SUNGMOON SYSTECH Corp.) and checking capacity retention ratio during galvanic cycling with 2032 coin half-cells. In addition, scanning electron microscope (SEM) and confocal optical microscope (VertScan, SUNGMOON SYSTECH Corp.) are employed for their morphological analysis.

References

[1] J. Choi et al., JPS, 2014, 252, 138

Acknowledgements

This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977)
Lithium Ion Thin-Film Electrodes for All-Solid-State and Electrochromic Applications
Authors: Röder Manuel , Posset Uwe , Buensow Johanna , Guntow Uwe , Lorrmann Henning , Guerfi Abdelbast , Zaghib Karim , Sextl Gerhard
Published: February 2020

Establishing thin-film technologies for lithium ion batteries is an important step towards all-solid-state batteries. Solid thin-film electrodes expose significantly higher charge and discharge rates than standard composite electrodes, thus have the potential to increase the power density of thin-film batteries.

Sol-gel procedures are established in battery research for synthesizing active material powders with controlled particle sizes. Here, we prepared single- and multi-layer films of active materials viadip-coating method. Both electrode single-layer systems exhibit excellent electrochemical properties such as high reversibility and low polarization in long-term CV measurements and show almost full capacity retention at charge and discharge currents up to 100 C.

Furthermore, applied on transparent conducting oxides, the electrodes were of high optical quality and showed intense color changes upon charging and discharging which positions them as interesting electrochromic compounds. Both materials are well known for their high reversibility and low cost compared to commonly known electrochromic metal oxides such as tungsten oxide.

The combination of their highly stable and very fast cycling capabilities with their color switching properties, make the presented transparent thin film electrodes promising candidates for high-power all-solid-state and electrochromic applications.

This paper shows transparent Li4Ti5O12 and LiMn2O4 thin film electrodes characterized by the above mentioned electrochemical measurements and their optical properties with the help of UV-vis spectroscopy. Additionally, material characterization is demonstrated via X-ray diffraction, XPS and SEM imaging.

Figure 1