bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Electrochemical Performance of SnS2 for Li-Ion Battery Anode By Engineering Interlayer Spacing
Authors: Tjalsma Jessica Ann , Wei Ping , Yang Jihui
Published: February 2020

Keywords:
layered SnS2, organic-inorganic composites, lithium-ion batteries, polymer restacking

The unique layered structure of transition metal dichalcogenides (TMDs) has historically been of great interest for energy storage applications because of the feasible ion intercalation/deintercalation within the van der Waals (vdW) gaps. Tin disulfide (SnS2) is a TMD that approaches twice the theoretical reversible gravimetric capacity of carbon (645 mAh/g vs. 372 mAh/g),1,2 the current anode of choice for lithium-ion batteries.2 In the present study, pristine SnS2 nanoflakes were prepared using a hydrothermal reaction. Subsequent exfoliation was achieved by intercalating n-butyllithium into the vdW gaps and reacting the LixSnS2 with dimethylformamide and distilled H2O. Once exfoliated, polymer was introduced either by direct addition or by polymerizing monomer in solution. X-ray diffraction shows a modified d-spacing along the c-direction of the resultant powders, indicative of successful restacking. Coin cells were constructed as a cathode/electrolyte/Li-metal configuration, with LiPF6 as Li salt and EC/DEC as solvent. Electrochemical tests were conducted from 0.1 V to 3.0 V at 0.1C-rate. Galvanostatic Intermittent Titration Technique was also employed to determine the diffusivity of Li-ions in the active material during cycling. By selectively expanding the vdW gaps, we probed the structure-property relationship of this nanocomposite material, and correlated how this expansion affects the barrier to Li+diffusion.

References

[1] T. Momma, N. Shiraishi, A. Yoshizawa, and T. Osaka, J. Power Sources, vol. 97–98, 2001.

[2] J.M. Tarascon, M. Armand, Nature, vol. 414, no. 6861, 2001.
New Findings in the Degradation of LiNi1-x-yCoxMnyO2 Cathode Material By Transmission Electron Microscopy
Authors: Xu Zhongling , Lang Ye , Gao Pengfei , Liu Na , Wang Long
Published: February 2020

Phase transitions and the related phase identifications for the layered rhombohedral Li(Ni1/3Co1/3Mn1/3)O2 with different electrochemical experience have been studied by transmission electron microscopy. The preliminary results show the existence of two types of new phases: spinel and rocksalt phases. The phase transition from rhombohedral to spinel phase happened only after formation and distributed on the surface of the particles, while the layered rhombohedral structure was kept inside.Another rocksalt phase was also identified on the surface of cycled sample which may getting thicker with the number of cycles. The phase transition from layered rhombohedral phase to spinel and then the rocksalt phase may explain the increased DCR and the capacity loss during cycling and storage. The twinning domains of layered rhombohedral phase were also found on the surface of the crystallite after 60°C storage at discharged state. The twinning domains on the surface may block the Li+ diffusion  space between the layers of the bulk, and thus make contribution to the DCR increase during storage.
Simulation of Lithium Dendrite Growth: Surface Morphology Effect
Authors: Byun Seoungwoo , Park Joonam , Appiah Williams Agyei , Lee Taejoo , Lee Young-Gi , Ryou Myung-Hyun , Lee Yong Min
Published: February 2020

Li metal has been considered as an anode material for lithium secondary batteries (LSBs) for over four decades. However, its uncontrolled chemical reactivity towards organic solvents and dendritic growth at random in electrochemical cells delayed its commercialization in the secondary battery market. Thus, without developing stable Li metal electrode, we will not encounter lithium-oxygen (Li-O2) and lithium-sulfur (Li-S) batteries as well as lithium metal secondary battery forever. However, regardless of tremendous endeavour to control the Li metal, unfortunately, the dendrite formation and growth mechanism has not been fully understood owing to the limited analysis in operando.

Therefore, we try to contruct a mathematical model to study the current distribution upon the Li metal and the growth rate of dendrites with a simulation tool, COMSOL Multiphysics 5.2. Since this simulation contains a moving electrode surface during electrodeposition process, the deformed geometry should be considered carefully. From these simulated results, we can have different dendrite growth behaviours depending on initial Li metal surficial morphology.

References

1. V. Srinivasan and J. Newman, Journal of the Electrochemical Society, 151, A1530 (2004).

2. P. Arora, M. Doyle, A. S. Gozdz, R. E. White and J. Newman, Journal of power Sources, 88, 219 (2000).

Acknowledgements

This work was supported by the international Collaborative Energy Technology R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No. 20158510050020) and by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977).

Figure 1
Electrochemical Reduction from a Single Particle to the Systems Level
Authors: Marschilok Amy C , Kirshenbaum Kevin , Bock David C , Brady Alexander B , Zhong Zhong , Takeuchi Kenneth J , Takeuchi Esther S
Published: February 2020

Understanding electrochemical behavior requires inquiry of the material fundamental properties as well as the behavior of the material when configured into a fully functioning device.  Thus, the ability to use local electrochemical probes and integrate the results with system level behavior is needed.  In this work, quantitative electrochemistry was conducted on individual particles of vanadium phosphorous oxides, (specifically SVPO, AgwVxPyOz) cathode materials. Silver ions incorporated into the layered vanadium phosphorous oxide structure facilitated monitoring of the reaction progress through the formation of silver metal.  The results obtained from the single particle were related to the systems level through in-situ examination of the reduction progress in fully assembled cells probed through energy dispersive x-ray diffraction, EDXRD.

  At the particle level, individual particles of active material, Ag2VO2PO4, were electrochemically reduced to various depths of discharge.  After the material was reduced, the conductivity of the individual particles was determined using a nanoprobe integrated with a scanning electron microscope, Fig. 1.  The individual particles showed a drastic reduction in local resistance when discharged.

At the system level, in situ energy dispersive X-ray spectroscopy (EDXRD) was used to probe Li/ Ag2VP2O8 cells at several stages of reduction, allowing depth profile analysis of the discharge process. This technique enables micron scale spatial resolution of reduced Ag2VP2O8 and Ag0 discharge products in the bulk electrode.  Results suggest the formation of a 3-dimensional Ag0 percolation network that increases conductivity throughout the entire electrode, occurs concurrently with a substantial decrease in the charge transfer resistance. The resistance of the reduced cathode is dependent upon discharge rate even in the presence of conductive additives.

Development of the next generation of battery systems with improved energy utilization requires accessing all of the active material in an electrode.  The multiscale inquiry methodology described provides a template for future investigations of both particle level and system level properties of electrochemically discharged materials highlighting the importance of advanced instrumental techniques to gain insight into complex discharge processes.

Figure 1
LiCoO2 and Silicon Electrodes for Wide Operating Temperature Range All-Solid-State Thin Film Lithium-Ion Batteries
Authors: Wang Yihua , Chen Yuan , Tang Zhe , Chua Daniel
Published: February 2020

All-solid-state thin-film lithium-ion batteries are a potential replacement for liquid electrolyte-based Li-ion batteries owing to their superior cycle life, high energy and power densities with an extremely low self-discharge rate at a wide operating temperature range. However, the state-of-art all-solid-state Li-ion batteries mainly use thermal-evaporated lithium metal as anode, which considerably undermines their cost-effectiveness and raises safety concerns of Li explosion. In this study, a layer structure LiCoO2/lithium phosphorus oxynitride (LiPON)/Si-based all-solid-state Li-ion battery has been successfully developed using sputter-deposition technique. This electrochemical active Li-free all-solid-state Li-ion battery exhibited superior cycling stability from 3.0 to 3.6  V with a wide operating temperature range from -25 to 120ºC. The higher operating temperatures of the LiCoO2/LiPON/Si-based all-solid-state Li-ion batteries are being investigated and further optimization is currently under way.
Selectively-Etched Silicon/Graphite Nanocomposites As Anode Materials for Li-Ion Batteries: Towards the Reduced-Cost Battery
Authors: Ashuri Maziar , He Qianran , Emani Satyanarayana , Shaw Leon
Published: February 2020

Silicon with more than 4000 mA h g-1 theoretical specific capacity is one of the most promising candidates for replacing conventional graphite anodes in Li-ion batteries. However, due to the huge volume change in cycling, the specific capacity fades fast. Several strategies have been proposed, but the best results were obtained by special designs (such as core-shell, yolk-shell, etc.) along with reducing grain size to nm scale. These strategies have improved the specific capacity dramatically, but most of them do not have the potential for mass production. Here, we report a facile synthesis method which is based on the idea of making composites of silicon and graphite, which are abundant and cheap. Silicon and graphite were mixed together with the weight ratio of 90:10 and high-energy ball milled before carbon coating via carbonization of pyrrole. The carbon-coated powder was then etched with 0.5 M NaOH solution to create carbon-encapsulated Si/graphite composites with engineered void (i.e., Si/graphite@void@carbon). For comparisons Si/graphite@void@carbon was also synthesized via carbon coating with polydopamine (PODA) as the precursor. Both Si/graphite@void@carbon powders were utilized to fabricate CR2032 coin cells with Li chip as the counter electrode. Electrochemical results of Si/graphite@void@carbon were compared to those of both micron- and nano-sized silicon particles and discussed.
Functional Electrolyte Additives for Improved Performance and Gas Suppression in Li4Ti5O12 / LiMn2O4 Li-Ion Battery Systems
Authors: Hoffmann Jennifer , Milien Mickdy S , Lucht Brett L , Li Jing , Payne Martin
Published: February 2020

Li4Ti5O12 (LTO) as a material for lithium ion batteries has garnered attention from industry and academia due to its increased safety properties, high rate capabilities, and exceptional cycling stability. The main concern arises in that cells using LTO anodes produce gas especially at elevated temperatures leading to swelling and decreased performance. It has been reported that this gassing is associated with the electrolyte and salt decomposition on the catalytic surface of the LTO anode1,3. In the open literature, efforts have been made to address the gassing issue through either coating on LTO materials2,4 or electrolyte technology3. In this work, we investigate the impact of various additives to the LTO-based cell performance in an electrolyte stabilization approach. Additives presented, including an electrolyte stabilizer, improved the electrochemical performance and reduced the gassing of pouch cells using LTO as anode and LiMn2O4 (LMO) as cathode.  These results of electrochemical tests, surface analysis of the anode and cathode through XPS and FTIR will be discussed in the meeting. The results presented prove that electrolyte stabilization through use of functional additives can allow the benefits of LTO to be harnessed and the gassing behavior to be controlled. 

References

Y. He, B. Li, M. Liu, C. Zhang, W. Lv, C. Yang, J. Li, H. Du, B. Zhang, Q. Yang, J. Kim, F. Kang, Sci. Rep. 2, 913 (2012)

L. Wang, K. Nakura, M. Imazaki, N. Kakizaki, K. Ariyoshi, and T. Ohzuku, J. Electrochem. Soc., 159, A1710 (2012)

J. Liu, P. Bian, J. Li, W. Ji, H. Hao, A. Yu, J. Pow. Sour., 286 (2015)

W. Li, X. Li, M. Chen, Z. Xie, J. Zhang, S. Dong, M. Qu, Elect. Acta., 139 (2014)
Evaluation of Electrolyte Resolution Behavior of 18650 Type Lithium Ion Battery By NMR Measurements
Authors: Haruna Hiroshi , Takamatsu Daiko , Hirano Tastumi , Takahashi Shin , Tanaka Yasutaka
Published: February 2020

Li-ion batteries are currently used in portable electronic and power tool and electric vehicles and grid energy applications due to their high energy density. The development of higher power, higher capacity and longer life batteries becomes more pressing. Current cycle life may be insufficient. One method to developing longer life cells is to use electrolyte additives such as vinylene carbonate to electrolyte solution which has been shown to significantly increase lifetime [1].In this report, the effects of vinylene carbonate an electrolyte additive were studied to improve battery life. VC was added to electrolyte solution to examine the impact in the solution structure change before / after cycling tests by 18650-type battery cells. All solutions were extracted from cycled 18650- type cells to detect solution composition by nuclear magnetic resonance (NMR) techniques.Compared with the case of no additives, VC that was included at 1 wt% concentration in the electrolyte at the initial state was reduced to half after only one cycle. Then it was completely consumed after 100 cycles due to be reacted at the interphase of positive/negative electrodes. Then the electrolyte composition change in until 100 cycles was slightly different with the addition of VC detected by NMR measurement. However, after 1000 cycles both electrolytes showed substantially the same composition. Ethyl methyl carbonate (EMC) which was one component of the electrolyte solution was decomposed and degradation products were produced in electrolyte solution. And the products were detected dimethyl carbonate and diethyl carbonate as the ester exchange reaction of EMC [2]. Furthermore NMR results showed poly-carbonate species from the polymeric reaction ethylene carbonate with non cyclic carbonate. Those were revealed by 1D as 1H or 13C NMR and 2D HMQC techniques. We will discuss relations of the resolution mechanism of the electrolyte with the degradation of the battery.

[1] J. Self, C.P. Aiken, R. Petibon, J.R. Dahn, J. Electrochem. Soc. 162(2015) A796-A802. [2] E. S. Takeuchi, H. Gan, M. Palazzo, R. A. Leising, S. M. Davis, J. Electrochem. Soc. 144(1997) 1944-1948.
Role of 1, 3-Propane Sultone and Vinylene Carbonate in Solid Electrolyte Interface (SEI) Formation and Gas Generation
Authors: Zhang Bo , Metzger Michael , Solchenbach Sophie , Payne Martin , Meini Stefano , Gasteiger Hubert A. , Garsuch Arnd , Lucht Brett L
Published: February 2020

Due to the uprising demand of energy storage in consumer electronics and electric vehicles, tremendous effort and interest have been drawn into the development of novel electrolyte additive blends in lithium-ion batteries (LIBs). However, the applications of LIBs have several critical limitations, including elevated temperature performance, calendar life performance, and safety. The solid electrolyte interface (SEI), generated from the electrolyte reduction on the anode surface during the first few cycles, is believe to be one of the key players improving LIBs thermal stability. Various attempts to screen ultimate electrolyte additive blends and produce robust SEI layer for better cyclability in lithium-ion batteries operations at elevated temperature have been widely reported. The graphite/LiNi1/3Co1/3Mn1/3O2 coin cells containing electrolytes with and without 1, 3-propane sultone (PS) and vinylene carbonate (VC) have been prepared and investigated. The electrochemical performance of the cells is correlated with ex-situ surface analysis of the electrodes conducted by FTIR and XPS, and in-situ gas analysis by on-line electrochemical mass spectrometry (OEMS). The results suggest that incorporation of both PS and VC results in improved capacity retention upon cycling at 55 °C and lower impedance. Ex-situ surface analysis and OEMS confirm that incorporation of PS and VC alter the reduction reactions on the anode inhibiting ethylene generation and changing the structure of the solid electrolyte interface (SEI).  Incorporation of VC results in CO2 evolution, formation of poly(VC), and inhibition of ethylene generation.  Incorporation of PS results in generation of lithium alkylsulfonate (RSO2Li) and inhibition of ethylene generation.  The combination of PS and VC reduces the ethylene gassing during formation by more than 60 %.
Critical Limiting Factors for High Performance Sodium Ion Batteries
Authors: Li Xin
Published: February 2020

The critical factors that limit the performance of layered sodium ion cathode materials are analyzed by a combination of theoretical simulation and experiments. These materials include quaternary, ternary, binary and single transition metal (TM) NaTMO2 layered structures. The capacity and cyclability are different among these layered structures depending on the various combinations of the transition metal ions, i.e. the transition metal combination based performance engineering. This work elucidates these critical factors that control the battery performance in terms of electrochemical structural and microstructural evolutions, and pointing out the engineering direction to high performance sodium ion batteries.
Investigation of NaxMgx/2Mn1-x/2O2 (1.0 > x > 1/3) for Na-Ion Battery Positive Electrodes
Authors: Zheng Lituo , Nguyen Peter , Obrovac Mark N
Published: February 2020

Introduction

Manganese-based layered oxide materials are promising positive electrode for sodium ion batteries. It has been shown that the partial substitution of Mn with Mg can smooth the voltage curve and improve the cycling stability.1 Mg substitution can also induce the activation of the redox reaction of oxide ions.2 In this study, the NaxMgx/2Mn1-x/2O2 (1.0 ≥ x ≥ 1/3) series of layered oxides were synthesized and characterized in Na cells.

Experimental

Stoichiometric amounts of MgO, MnO and Na2CO3 were combined by ball milling, then heated at 900 ºC in air to obtain samples of

NaxMgx/2Mn1-x/2O2.  Electrodes were made with active material, PVDF binder, carbon black at a ratio of 8:1:1 and dried under vacuum at 120 ℃ overnight. 1M NaPF6 in a solution of EC, DEC, FEC (volume ratio 3:6:1) was used as electrolyte and Na foil was used as counter/reference electrode. X-ray diffraction (XRD) patterns were measured with a Rigaku Ultima IV X-ray diffractometer equipped with a Cu anode X-ray tube and a diffracted beam monochromator.

Results and discussion

Figure 1 shows the XRD patterns of NaxMgx/2Mn1-x/2O2 (1.0 ≥ x ≥ 1/3). All the samples were found to be P2-dominant, even when x approachs 1. The sample with x = 2/3 has the highest P2 phase purity. The further x deviates from 2/3, the more impurities are present in the XRD patterns.

Figure 2 shows the voltage curve of Na2/3Mg1/3Mn2/3O2. Na2/3Mg1/3Mn2/3O2 was found to have a reversible capacity of ~250 mAh/g (corresponding to a theoretical energy density of approximately 520 Wh/kg) with 80% capacity retention after 20 cycles. The voltage curve exhibits a plateau at > 4 V during the first charge, and a slope between 1.5 V and 3.5 V during discharge. The loss of capacity of the 4 V plateau during cycling indicates irreversible structure changes upon first charging, possibly due to oxygen loss.  After about 10 cycles, the 4 V plateau becomes stabilized and the material cycles reversibly.

The voltage curve of Na2/3Mg1/3Mn2/3O2 is consistent with the voltage curve of Li2MnO3, wherein all the Mn is also in the 4+ oxidation state. This result is the first report of the reversible sodium extraction from layered manganese oxide materials where all the Mn exist as Mn4+.

References

1. J. Billaud et al., Energy Environ. Sci., 7, 1387-1391 (2014)

2. N. Yabuuchi et al., J. Mater. Chem. A, 2, 16851-16855 (2014)

Figure 1
Raman Mapping for LiCoO2 Composite Positive Electrodes in All-Solid-State Lithium Batteries Using Li2S-P2S5 Solid Electrolytes
Authors: Otoyama Misae , Ito Yusuke , Hayashi Akitoshi , Tatsumisago Masahiro
Published: February 2020

All-solid-state batteries with nonflammable inorganic solid electrolytes, an alternative to conventional inflammable organic liquid electrolytes, are widely studied as next generation batteries with low risk of leakage and explosion. Bulk-type batteries use composite electrodes of active materials and solid electrolytes. Solid electrolytes play a role of delivering Li ions to active materials. Bulk-type batteries are capable of having high energy density by adding large amounts of active materials into composite electrodes. We have investigated the electrochemical performance of bulk-type all-solid-state cells using a LiCoO2 composite positive electrode and a Li2S-P2S5 solid electrolyte [1]. Composite electrodes can be fabricated by mixing LiCoO2 particles and solid electrolyte particles. There are many solid-solid interfaces in composite electrodes. It is important that electrochemical reactions at LiCoO2-electrolyte solid-solid interfaces are clarified to improve the cell performance. Raman microscopy is one of the useful methods for investigating the reactions because of its feature of high spatial resolution and surface sensitivity. Raman spectral changes of composite electrodes are closely related to the structural changes of active material during charge-discharge cycling. In this study, Raman spectroscopy was carried out for LiCoO2 composite positive electrodes in all-solid-state cells before and after the charge-discharge process. Moreover, Raman mapping was conducted to evaluate state-of-charge (SOC) distributions of each active material in the electrodes.

   The 75Li2S·25P2S5 (mol%) glass and indium foil were used as solid electrolyte and a negative electrode, respectively. A composite positive electrode was prepared by mixing LiCoO2 particles and 75Li2S·25P2S5 glass particles (80:20 wt.%). All-solid-state cells were charged and discharged with a cut-off voltage of 2.6-4.2 V (vs. Li+/Li) at 25 oC under a current density of 0.064 mA cm-2. Raman spectra were obtained for the surface part of composite positive electrodes prepared by an Ar ion-milling technique.

   There are two strong Raman peaks at 486 and 596 cm-1, originating from the E
g and A
1g modes of oxygen vibration in LiCoO2, respectively. Those peaks shifted to the lower wavenumber side and their intensity decreased after the initial charging process. After the discharging process, those peaks returned to the original positions. Mapping images showed charge-discharge reactions did not proceed uniformly at the areas of insufficient contacts between LiCoO2 particles and solid electrolyte particles [2]. Our approaches to fabricate composite positive electrodes having uniform charge-discharge reactions will be demonstrated.

Acknowledgement

This research was financially supported by JST, ALCA-SPRING.

References

[1] T. Minami et al., Solid State Ionics, 177 (2006) 2715-2720.

[2] M. Otoyama et al., J. Power Sources, 302 (2016) 419-425.
Ni3Sn4 Based Anode Materials for Three-Dimensional Lithium/Sulfur Battery
Authors: Tolegen Beisen , Pidakhmet Aidyn , Mentbayeva Almagul , Hara Toru , Bakenov Zhumabay
Published: February 2020

The development of renewable energy and ecological transport demands high energy density rechargeable batteries. Conventional battery technologies suffer from high cost, toxicity and performance limitations such as low capacity and capacity fading. Therefore, development of novel economically feasible high performance batteries is crucial for wider use and application of sustainable energy supply and electric vehicles. Lithium/sulfur (Li/S) batteries have the highest energy density among all known systems [1], and therefore are promising as the next generation batteries. However, these systems have disadvantages related to low conductivity of sulfur and its dissolution and shuttle during the battery operation.

Mosby and Prieto have demonstrated an innovative concept of economically feasible three-dimensional (3D) battery manufacturing concept [2]. The aim of our work is to develop an innovative battery by combining 3D battery architecture with outstanding performance of Li/S technology. In the current work focus was to construct a safe three-dimensional battery with high energy efficiency and stable cycling. Here we show that consistent progress has been achieved and three-dimensional anode was prepared: Ni3Sn4 alloys were successfully electrodeposited on nickel foam and their structural and electrochemical properties were examined. This 3D battery architecture will be combined with the Li/S battery technology, which will allow to overcome the large volume changes in the anode by making nano-sized anode crystals and tightly connecting these crystals to the 3D current collector. Sulfur cathode, which is converted into soluble catholite during charging/discharging, can be impregnated into the 3D architecture more easily than conventional cathode materials. This system is promising as a potential electric vehicle battery and the energy storage system for renewable energy sources.

Reference

[1] Y. Zhang, Y. Zhao, Z. Bakenov, “A novel lithium/sulfur battery based on sulfur/graphene nanosheet composite cathode and gel polymer electrolyte,” Nanoscale Res. Lett., 2014, 137.

[2] J. Mosby, L. Prieto, “Direct electrodeposition of Cu2Sb for lithium-ion battery anodes,” J. Am. Chem. Soc., 2008, 130, 10656-10661.

Acknowledgments

This work was supported by the research grant #4649/GF4 “Development of economically feasible three-dimensional lithium/sulfur battery” from the Ministry of Education and Science of the Republic of Kazakhstan.
A Surface Enhanced Raman Spectroscopy (SERS)-Active Cathode for Lithium-Oxygen Battery Discharge Product Investigation
Authors: Liu Kewei , Yu Zitian , Zhu Xiaowen , Zhang Shuo , Zhu Yu
Published: February 2020

Nonaqueous Lithium-air (Li-O2) battery has attracted significant research interest in the past decade, because of its high theoretical specific energy far beyond conventional Li-ion battery. However, there are many challenges such as severe degradation during cycling that limits the practical utilization of Li-O2 battery. Hence, a powerful tool is necessary to be found to detect the intermediates and study side reactions in Li-O2 battery. In this work, we explored a method to fabricate larger-area regularly patterned gold nano-dots by using the mask of anodic aluminum oxide (AAO) membrane for surface enhanced Raman spectroscopy (SERS).  The size effect of the small and large gold nano-dots on the enhancement of Raman signal was studied by Rhodamine 6G on Si. Small gold nano-dots on Au film and graphene were used as SERS-active cathodes in Li-O2 battery and showed great ability for detecting the component on planar electrode. After discharge, many peaks have been observed for the SERS-active gold electrode, which demonstrate the existence of Li2O2, LiOH and LiO2. On the other hand, when SERS-active graphene electrode was used as lithium oxygen battery cathode, Li2O2 and Li2CO3 were detected.
The Development of Sodium Sulfur Batteries for Energy Storage Application in China
Authors: Liu Yu
Published: February 2020

Sodium sulfur batteries with a high energy density have been widely demonstrated by NGK INSULATORS, LTD, Japan, which is the only one maker for soduim sulfur batteries reported through the world  Based on the technology developed from Shanghai Institute of Ceramics Chinese Academy of Sciences, a manufacture company of Shanghai Electric Sodium-sulfur Batteries Energy-Storage Technology Co.Ltd, abbreviated as SESSE, has been established at Jan., 2012. So far, the company has completed a 10 MW-per year scale for the fabrication of sodium sulfur batteries.The large size beta Al2O3 ceramic tubes are mass produced by the common ceramic fabrication technology such as dry bag molding and gas sintering. The market goal of sodium sulfur batteries developed currently is the energy storage application for renewable energy, emergency energy and smart grid. Based on the market requirement, such as power output, energy capacity, and system scale, different types of the modules such as 5Kw and 25 KW have been developed.The 1MWh power station of sodium sulfur batteries for energy storage located in Shanghai has been constructed and operated since March, 2015.  The detailed information and situation  will be introduced and presented in this conference.
Surface-Chemistry-Initiated Design of Host Materials for Sulfur Cathodes: From Nitrogen-Doped Carbon to Sulfiphilic Cobalt Disulfide
Authors: Peng Hong-Jie , Yuan Zhe , Hou Ting-Zheng , Huang Jia-Qi , Cheng Xin-Bing , Wei Fei , Zhang Qiang
Published: February 2020

The development of lithium−sulfur batteries has become an important area of research to meet the growing demand of modern society for energy-storage devices as sulfur cathode is benefited from the excellent theoretical capacity of 1672 mAh g−
1, low cost, abundant reserves, and environmental benignity. However, its practical application is strongly impeded by the sluggish kinetics of sulfur redox within aprotic electrolytes and the shuttle effect of soluble intermediate polysulfides. The incompatibility between highly polar polysulfides and conventional carbonaceous conductive substrates is believed to be the main reason for both unfavorable redox activity and polysulfide “flooding”.1 Here two host materials for sulfur cathodes beyond typical nanocarbon are presented. (1) Nitrogen-doped carbon nanotubes were employed to build sulfur composite cathodes and to examine the heteroatom-doping effect on the sulfur electrochemistry. The electrochemical measurements combined with ab initio calculation validated an enhanced capacity of 1370 mAh g−
1 at 0.1 C, over eight-times extended cyclic life, and reduced polarization via only 1.8 % nitrogen incorporation.2 (2) The sulfiphilic surface properties of bulk cobalt disulfide (CoS2) was demonstrated by static adsorption and theoretical calculation. Further hybridization of 15 % CoS2 with graphene demonstrated a high capacity of 1368 mAh g−
1 at 0.5 C, low decay rate of 0.034% over 2000 cycles at 2.0 C, and 10 % increase in energy efficiency. More importantly, the electrocatalytic effect on liquid−liquid polysulfide redox was first verified by assembling symmetric cells.3The two surface-chemistry-initiated design is believed to bring new opportunity to propel the development of advanced sulfur lithium−sulfur batteries as well as other novel energy storage devices.

References:

Peng, H.-J.; Zhang, Q. Angew. Chem. Int. Ed.
2015, 54, 11018–11020

Peng, H.-J.; Hou, H.-Z.; et al. Adv. Mater. Interfaces
2014, 1, 1400227

Yuan, Z.; Peng, H.-J.; et al. Nano Lett.
2016, doi: 10.1021/acs.nanolett.5b04166
MoS2 Nanosheets Vertically Aligned on Carbon Paper: A Freestanding Electrode for Highly Reversible Sodium Ion Batteries
Authors: Xie Xiuqiang , Makaryan Taron , Zhao Mengqiang , Van Aken Katherine L , Gogotsi Yury , Wang Guoxiu
Published: February 2020

The renaissance of sodium-ion batteries (SIBs) in the last few years provides a promising environmentally friendly alternative for energy storage and conversion (ESC).1
,
2 MoS2, a layered material with a large interlayer spacing along the c-axis (0.62 nm), has been attracting extraordinary attention as anode materials for SIBs. However, pure MoS2 exhibited poor rate capability and fast capacity decay upon cycling. Nanostructuring and hierarchical electrode architectures are required to facilitate transport of Na-ions within electrodes.3 Herein,  we report on a rational design of freestanding anode materials for sodium-ion batteries, consisting of MoS2 nanosheets aligned vertically on carbon paper derived from paper towel.4 The hierarchical structure enables sufficient electrode/electrolyte interaction and fast electron transportation. Meanwhile, the unique architecture can minimize the excessive interface between carbon and electrolyte, enabling high ICE. When employed as freestanding electrodes for SIBs, the as-prepared MoS2@carbon paper composites delivered a high reversible capacity of 446 mA h g-1 at 20 mA g-1, high ICE (79.5%), and promising rate capability. Even at a high current density of 1000 mA g-1, a reversible capacity of 205 mA h g-1 was maintained.By exploiting in situ Raman spectroscopy, we observed the reversibility of the phase transition from 2H-MoS2 to 1T-MoS2 during the sodium-ion intercalation/de-intercalation process.

References

1. Xiuqiang Xie, Zhimin Ao, Dawei Su, Jinqiang Zhang and Guoxiu Wang, MoS2/graphene composite anodes with enhanced performance for sodium-ion batteries: the role of the two-dimensional heterointerface,
Advanced Functional Materials
, 2015, 25, 1393-1403.

2. Xiuqiang Xie, Katja Kretschmer, Jinqiang Zhang, Bing Sun, Dawei Su and Guoxiu Wang, Sn@CNT nanopillars grown perpendicularly on carbon paper: A novel free-standing anode for sodium ion batteries,
Nano Energy
, 2015, 13, 208-217.

3. Yury Gogotsi, What nano can do for energy storage,
ACS Nano
, 2014, 8, 5369-5371.

4. Xiuqiang Xie, Taron Makaryan, Mengqiang Zhao, Katherine L. Van Aken, Yury Gogotsi and Guoxiu Wang, MoS2 nanosheets vertically aligned on carbon paper: a freestanding electrode for highly reversible sodium-ion batteries,
Advanced Energy Materials
, 2015, DOI: 10.1002/aenm.201502161.

Figure 1
Kinetics Tuning of Li-Ion Diffusion in Layered Li(NixMnyCoz)O2
Authors: Zheng Jiaxin , Wei Yi , Cui Suihan , Amine Khalil , Pan Feng
Published: February 2020

Understanding and further designing new LiNixMnyCozO2 (NMC) (x + y + z = 1) materials with optimized transition metals contents is an important way to meet high power density applications for rechargeable Li batteries (LIBs). Using ab initio calculations combined with experiments, we investigate the kinetics of Li-ion diffusion vs. selection of advantage paths and their effective diffusion barriers depended on activation energies and Li-slab space in NMC materials systematically. It is found that Li-ions tend to choose oxygen dumbbell hopping (ODH) at the early stage of charging (delithiation), and tetrahedral site hopping (TSH) begins to dominate when more than 1/3 Li-ions are extracted. Apart from this, in both ODH and TSH, the Li-ions surrounded by nickel (especially with low valence state) are more likely to diffuse with low activation energy and form an advantage path. The Li slab space, which also contributes to the effective diffusion barriers, is found to be closely associated with the delithiaton process (Ni oxidation) and the contents of Ni, Co, and Mn. Therefore, the kinetics of Li-ion diffusion in layered NMC materials can be tuned by the Li content (delithiation process) as well as the different contents of Ni, Co, and Mn in NMC materials. Based on these discovers, we finally propose that developing Li[Ni0.5Mn0.5]1-xCoxO2 (0 < x ≤ 0.33) system is a most promising way to further optimize the performance of NMC materials.

Figure 1
Electrochemical and Structural Investigations of Titanate Based Anodes for High Power and Long Cycle Life Li-Ion Battery
Authors: Choi Daiwon , Cartmell Samuel , Han Keesung , Huang Qian , Thomsen Ed , Xu Wu , Viswanathan Vish , Sprenkle Vincent
Published: February 2020

Increasing demands for utilization of intermittent renewable energy resources, cost effective, safe and long cycle life electrochemical energy storage is required. Currently, lithium-ion batteries are identified as strong contender to fulfill the future energy requirements for electric vehicle as well as stationary energy storage applications due to high voltage, energy density, and long cycle life. However, state-of-the-art lithium ion battery technology still needs improvements in terms of cost, safety, power and cycle life. For stationary application, energy density is not as critical as that for vehicle application but long cycle life and safety is required. The spinel-type lithium titanium oxide, Li4Ti5O12 is attractive as an alternative to graphite anode for advanced lithium-ion batteries, due to the reversible Li insertion and extraction property at around 1.55 V (versus Li/Li+) with so called zero strain behavior. Even though this redox potential is far higher than that of graphite or carbonaceous materials, the good cyclability of Li cells has favored its commercialization. Although the structural restriction of the spinel structure limits the theoretical capacity to 175 mAh/g, various forms of titanate compounds exists such as H2Ti6O12, H2Ti12O25 and TiO2(B) with a higher theoretical capacity up to 335 mAh/g. In our presentation, electrochemical performance of Li-ion pouch cell using NMC cathode and AlF3 coated Li4Ti5O12 anode combination will be presented. Furthermore, structural investigations and electrochemical performances of other titanate based anodes will be discussed.
In Situ Stress Measurements during Electrochemical Activation in Li2MnO3-Based Cathodes
Authors: Nation Leah , Li Juchuan , James Christine , Qi Yue , Dudney Nancy J , Sheldon Brian W.
Published: February 2020

Lithium-Rich NMC (Li2MnO3-LMO2) is an attractive cathode material for lithium ion batteries due to its high reversible capacity above 200 mAh/g. The Li2MnO3 component contributes to the high capacity through an activation process in the first delithiation cycle. During activation, oxygen and lithium are removed from the structure, causing compositional stresses that lead to mechanical degradation. In this study, LR-NMC thin-films are prepared by sputtering on sapphire substrates and characterized using XRD, Raman spectroscopy, and SEM. A Multibeam Optical Stress Sensor is used to quantitatively measure stress in the cathode film during electrochemical cycling. A unique stress signature is observed during the first charge when activation occurs. Initially, a tensile stress is observed, consistent with volume contraction from lithium removal. The stress reverses and becomes compressive with continued charging beyond 4V vs Li/Li+, indicating volume expansion; this phenomenon is present in the first cycle only. The origin of this irreversible stress during the first charge is not clear; cracking and oxygen loss are explored as possible causes. Subsequent cycling is reversible, with volume expansion during lithiation and volume contraction during delithiation. Raman spectroscopy provides evidence of the layered-to-spinel phase transition after cycling past the activation plateau, as well as recovery of the original spectra upon reannealing in an oxygen environment. Atomistic modelling in conjunction with experimental results aids in understanding the effects of stress on kinetics and phase transformations, guiding the development of improved Li2MnO3-LMO2 cathodes.
Voltage Fade Phenomenon and Structural Stability of Lithium- and Manganese-Rich Nickel-Manganese-Cobalt Oxides
Authors: Bareno Javier , Li Yan , Vu Anh , Phillips Patrick J , Bettge Martin , Klie Robert F , Chen Zonghai , Abraham Daniel P , Bloom Ira
Published: February 2020

Lithium- and Manganese-Rich Nickel-Manganese-Cobalt Oxides (LMR-NMC), nominally of composition xLi2MnO3
•(1-x)LiMO2 (with M a combination of Ni, Mn, and/or Co), present a high-voltage plateau (~4.5 V vs. Li/Li+) in their capacity-voltage profile during the first delithiation cycle.  This plateau is believed to result from activation of the Li2MnO3component, which makes additional lithium available for electrochemical cycling.  Once activated (i.e., cycled beyond the activation plateau) the voltage v. capacity characteristic of LMR-NMC oxides is known to decrease continuously with cycling, resulting in a progressive loss of energy density.  This phenomenon, commonly referred to as voltage fade, results in a gradual loss of energy density with cycling and constitutes one of the main barriers toward broad application of LMR-NMC as cathode materials for automotive applications.

In this work we show evidence of voltage fade well below the activation plateau and its relation to structural changes during LMR-NMC cycling.  We argue that voltage fade results from a gradual accumulation of spinel environments in the crystal structure.  Some of these spinel sites result from lithium deficiencies during oxide synthesis and are likely to be at the particle surfaces; other sites result from the migration of transition metal atoms in the partially-delithiated LiMO2component into the lithium planes during electrochemical cycling.  We also present evidence that these structural changes are related to the oxygen-to-metal ratio and could be driving oxygen evolution from LMR-NMC materials which, as a potential trigger of thermal runaway, is a process of fundamental concern for safety. 

Acknowledgment: The submitted issue has been created by the University of Chicago as Operator of Argonne National Laboratory (“Argonne”) under Contract No. W-31-109-Eng-38 with the U.S. Department of Energy. The U.S. Government retains for itself, and others acting on its behalf, a paid-up, non-exclusive, irrevocable, worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.
Novel Method of Contrast Improvement Applied to Lithium Ion Battery Electrode Materials Enabling Multi Modal and Super-High Resolution 3D Imaging and Advanced Quantification
Authors: Biton Moshiel , Yufit Vladimir , Tariq Farid , Kishimoto Masashi , Brandon Nigel P.
Published: February 2020

The authors present for the first time a new methodology of contrast enhancement for multi modal 3D imaging including novel advanced quantification for a commercial Lithium Iron Phosphate (LFP) LiFePO4 cathode. The research aim of this work is to improve the 3D imaging of challenging battery materials by developing methods to increase the contrast between otherwise previously poorly differentiated phases. This is necessary to enable the capture of the real geometry of electrode microstructures, which allows measurement of a wide range of microstructural properties such as pore/particle size distributions, surface area, tortuosity and porosity. Those properties play vital roles in determining the performance of battery electrodes. In this study we present a novel method of sample preparation which is introduced here for the first time for this purpose and found suitable for multi modal imaging, for both FIB-SEM tomography and X-ray tomography.  This novel method improves image contrast, which enables higher FIB-SEM resolution (3D image) the highest yet reported for carbon containing electrode materials (e.g. composite LFP cathodes) using FIB-SEM. It means that all the particles are well defined and the size distribution of each phase can be analysed very accurately from the complex 3D electrode microstructure using an advanced novel quantification algorithm.
Study the Performance of LiCoO2 for 4.5V Lithium Ion Battery
Authors: Han Guangshuai , Li Wei , Xie Jingying
Published: February 2020

As the world into the era of 3G/4G, 3G/4G phones and netbooks gradually popular, mobile Internet, games, video more extensive application of all these applications need to be on the phone for a long time operation, the need of mobile phone battery can support a long time, it puts forward higher requirements on lithium ion batteries, thus to improve the specific energy of lithium ion battery has become one of the problems to be solved1-2. At present mainly in order to improve the specific energy of lithium ion battery by boosting voltage of LiCoO2 material, while it will also bring adverse effect to LiCoO2 materials. So it is necessary to study the evolution of the LiCoO2under high voltage cycling.

In this paper, we used the three electrodes to monitor the potential changes of LiCoO2 and graphite from the battery initial state charged to 4.5 V (as shown in figure 1), and before and after cycling. Study the morphology, structure and surface changes of LiCoO2before and after cycling under 4.5V high voltage by using differential capacitance, scanning electron microscopy, X-Ray Diffraction (as shown in figure 2), Raman, IR and differential scanning calorimetry analysis characterization methods.

Acknowledgements

The project was supported by the Shanghai Science and Technology Development Fund (15DZ2282000) and (14JC1491800)

References

[1]. A. Aboulaich*, K. Ouzaouit, H. Faqir, A. Kaddami, I. Benzakour, I. Akalay. Materials Research Bulletin 73 (2016) 362-368.

[2]. Y. Ito, Y. Sakurai, S. Yubuchi, A. Sakuda, A. Hayashi∗,and M. Tatsumisago, J. Electrochem. Society, 162 (8) (2015) A1610-A1616.

Figure 1
Electronic-Structure Analyses of Li-Ion-Battery Electrodes By Soft X-Ray Absorption/Emission Spectroscopy Including Operando experiments
Authors: Asakura Daisuke , Hosono Eiji , Niwa Hideharu , Kiuchi Hisao , Miyawaki Jun , Nanba Yusuke , Okubo Masashi , Matsuda Hirofumi , Oshima Masaharu , Harada Yoshihisa
Published: February 2020

Improving the energy density and power density of electrode materials for Li-ion batteries (LIBs) is highly important to further develop electric and hybrid-electric vehicles. For the improvements, understanding the charge-discharge mechanisms from a viewpoint of the electronic structure is indispensable. Recently, electronic-structure analyses of the electrode materials using soft x-ray spectroscopy have been of particular importance.

In this study we demonstrate operando Mn L
3 soft x-ray emission spectroscopy (XES) for LiMn2O4 [1] which is a typical cathode material of LIB. We developed an operando cell consisting of the LiMn2O4 cathode, a counter electrode and an electrolyte solution [2] by modifying the in situ cell for fuel cell catalysts [3]. The charge-discharge experiments were performed by cyclic voltammetry. The operando XES experiments were carried out using ultrahigh-resolution x-ray emission spectrometer [4] at BL07LSU of SPring-8. The XES spectra were analyzed by theoretical analyses based on the configuration-interaction full-multiplet (CIFM) calculation [5-7].

In the operando Mn L
3 XES study for LiMn2O4, we revealed that the open-circuit voltage (OCV) state is almost the same as the initial state consisting of the Mn3+ and Mn4+ states. For the charged state, the Mn L
3 XES spectrum largely changed corresponding to the oxidation of Mn3+ to Mn4+ state at the Mn3+ site for the OCV. The spectrum for the discharged state almost returned to the spectrum for the OCV, while the small difference indicates that the Mn3+ state is slightly enhanced for the discharged state. Thus, the Mn 3d electronic states were reversibly changed for the charge-discharge process [2]. Moreover, charge-transfer (CT) effects between the Mn 3d and O 2p orbitals for each valence state were clarified. For the Mn4+ state, a negative CT energy was determined by the CIFM calculation, suggesting a very strong CT effect from the O 2p to Mn 3d orbitals.

In the presentation, XES and soft X-ray absorption spectroscopy studies for other electrode materials will also be reported, and the relationship between the electronic structure and electrochemical performance will be discussed.

References

[1] M. M. Thackeray, Prog. Solid St. Chem. 25, 1 (1997).

[2] D. Asakura et al., Electrochem. Commun. 50, 93 (2015).

[3] H. Niwa et al., Electrochem. Commun. 35, 57 (2013).

[4] Y. Harada et al., Rev. Sci. Instrum. 83, 013116 (2012).

[5] Y. Nanba et al., J. Phys. Chem. C 116, 24896 (2012).

[6] Y. Nanba et al., Phys. Chem. Chem. Phys. 16, 7031 (2014).

[7] D. Asakura et al., J. Phys. Chem. Lett. 5, 4008 (2014).